what i think is amazing is that solar system HD 69830 has a planet in the habbital zone. with an astroid belt ahead of it i can see a moon with life their. it may have a moon like that but maybe not. this planet in the habbital zone must have very many moons maybe more that saturn 60 sum-od moons

OK, I'll take the bait. Why must it have many moons?

If you look at our solar system the planets closest to the Sun have the fewest moons, Mercury and Venus both have zero, Earth only one (although the Earth/Moon are unusual in that they nearly constitute a double planetary system) and Mars only two. Even tiny Pluto manages 3 known moons.

When planets orbit close to their star then the stars gravitational attraction is strong, even dominant. The result of this is that a moon around such a planet tends to develop a chaotic orbit and is likely to be ejected from the planets orbit. The Neptune size planet which exists within the HD 69830 habitable zone (the outer most HD 69830d), orbits just 0.63 AU from the star, that's closer than Venus orbits the sun. (The same process occurs with planets and their moons, this is why, even though it is a large body, our Moon is unable to hold on to satellites of its own).

The second factor that has to be taken into account is that this planet is Neptune class rather than Jupiter or super Jupiter class. Is it likely that it will have a planet sized moon? Even Earth's moon is too small to have retained an atmosphere.

The universe is full of surprises and you might be right but I would say that the odds aren't good.

The Penn State University, Eberly College of Science press release is reproduced below:

2 August 2007—A planet orbiting a giant red star has been discovered by an astronomy team led by Penn State's Alex Wolszczan, who in 1992 discovered the first planets ever found outside our solar system. The new discovery is helping astronomers to understand what will happen to the planets in our solar system when our Sun becomes a red-giant star, expanding so much that its surface will reach as far as Earth's orbit. The star is 2 times more massive and 10 times larger than the Sun. The new planet circles the giant star every 360 days and is located about 300 light years from Earth, in the constellation Perseus. A paper describing the discovery will be published in a November 2007 issue of the Astrophysical Journal.


Alex Wolszczan (left) and Lawrence W. Ramsey
Credit: Penn State

The discovery resulted from an ongoing effort that the research team began three years ago to find Jupiter-mass planets around red-giant stars that are typically farther from Earth than those included in most other planet searches. "After astronomers have spent more than 10 years searching for planets around Sun-like stars and discovering over 250 planets elsewhere in our galactic neighborhood, we still do not know whether our solar system's properties, including life-supporting conditions on our planet, are typical or exceptional among solar systems throughout the Galaxy," Wolszczan says. "The picture for now, based on the searches for planets around stars like our Sun, is that our planetary system appears to be unusual in a number of ways."

Click on image for high-resolution file.

Credit: Lawrence W. Ramsey, Penn State

The Hobby-Eberly Telescope, one of the largest and most
powerful telescopes in the world, photographed at dusk by
Penn State Astronomer Lawrence W. Ramsey, a leader in
the conception, design, construction, and operation of the
telescope.

"This planet is the first one discovered by Penn State astronomers with the Hobby-Eberly Telescope, and it is in one of the most distant of the ten published solar systems discovered around red-giant stars," comments Lawrence Ramsey, a member of the discovery team and the head of the Department of Astronomy and Astrophysics at Penn State. Ramsey is a leader in the conception, design, construction, and operation of the Hobby-Eberly Telescope. "We are now becoming serious participants in planetary searches and planetary astronomy using the Hobby-Eberly Telescope," he says.

Astronomers now are branching out with different strategies for searching for planets, with the hope of more quickly detecting life elsewhere in the universe, of discovering all the possible kinds of solar systems, and of learning how they form around different kinds of stars. Wolszczan's team used one of these new strategies -- searching for planets around giant stars, which have evolved to a later stage of life than our Sun's.

"We have compiled a catalog of nearly a thousand giant stars that are candidates for hosting solar systems," Wolszczan says. Because the method for discovering planets involves repeated measurements of their gravitational effect on the star they circle, and because planets around red giants can take years to make one orbit around the star, the research team is just now beginning to reap discoveries from years of systematic observations. "It took us 3 years to gather enough data on over 300 stars to start identifying those that are good candidates for having planetary companions," Wolszczan said. "This planet is just the first of a number of planet discoveries that this research program is likely to produce."

This research is a collaboration between astronomers at Penn State, Nicholas Copernicus University in Poland, the McDonald Observatory, and the California Institute of Technology. "One important aspect of this work is that it marks the debut of a research group in Poland, led by Dr. Andrzej Niedzielski, which has become a serious contributor to discoveries in extra-solar planetary astronomy," Wolszczan said.

One reason for studying solar systems that include red-giant stars is that they help astronomers to understand more about the future of our own solar system -- as family photos can give children an idea of what they might look like when they are the age of their grandparents. "Our Sun probably will make the Earth unhabitable in about 2 billion years because it will get hotter and hotter as it evolves on its way to becoming a red giant about 5 billion years from now," Wolszczan says. As the star swells up, transforming itself into a red giant, it affects the orbits of its planets and the dynamics of the whole planetary system, causing such changes as orbit crossings, planet collisions, and the formation of new planets out of the debris of those collisions. "When our Sun becomes a red giant, Earth and the other inner planets very likely will dive into it and disappear," Wolszczan says.

Another motivation for studying red-giant stars is to understand how their habitable zones move farther out as the star's radiating surface becomes bigger. Based on how long it took for life to develop on Earth, scientists speculate that there is more than enough time during a star's giant phase for life to get a start somewhere in the evolving habitable zones. "In our solar system, places like Europa -- a satellite of Jupiter that now is covered by a thick layer of water ice -- might warm up enough to support life for more than a billion years or so, over the time when our Sun begins to evolve into a red giant, making life on Earth impossible," Wolszczan said.

Click on image for high-resolution file.

Credit: Lawrence W. Ramsey, Penn State

The Hobby-Eberly Telescope, one of the largest and most
powerful telescopes in the world, photographed at dusk by
Penn State Astronomer Lawrence W. Ramsey, a leader in
the conception, design, construction, and operation of the
telescope.

The method the astronomers use to discover planets is to observe candidate stars, repeatedly measuring their space velocity using the Doppler effect -- the changes in the star's light spectrum that result from its being pulled alternately toward and away from Earth by the gravity of an orbiting planet. "When we detect a significant difference in a star's velocity over a month or two, we then start observing that star more frequently," Wolszczan says. "In this paper, the velocity of the star changed by about 50 meters per second (about 100 miles per hour) between our first and second observations, so we observed that star more frequently and we found a clearly repeatable effect, indicating the presence of a planet." A star and its orbiting planet move around the center-of-mass of the whole system, so the star alternately approaches and recedes from Earth periodically. "When the star gets closer to us, its light becomes a little bit bluer and when it recedes from us, its light becomes redder, and we can measure that effect to deduce the presence of planets," Wolszczan explains.

Searching for planets around giant stars also is a clever way to learn about the formation of planets around stars more massive than our Sun. Because massive stars are so hot when they are in the phase of life of our Sun, astronomers have not been able to detect enough of their spectral lines to use the Doppler-spectroscopy method of finding planets. However, these stars become cooler as they evolve into giants, at which point the spectral-line observations needed for Doppler detection of planets become possible. "We want to know how often do planets form around stars that were more massive than our Sun," Wolszczan said. "Obviously, the more solar systems around red giants we discover and study, the better chance we have to really understand the big picture of planet formation."

Another reason astronomers are trying to discover planets around different kinds of stars at different stages of stellar evolution is to find out how different kinds of planetary systems change when their stars become red giants and how they ultimately end their lives as burnt-out, shrunken white-dwarfs.

"We really are at the very beginning of this effort and it is going to take time to get a consistent picture of planetary formation and evolution," Wolszczan says. "The more we learn, the greater the chance will be that sooner or later we will discover how ordinary or extraordinary is our home -- the Earth's solar system."

This research received financial support from NASA's Jet Propulsion Laboratory, Penn State's NASA-funded Astrobiology Program, the Polish Ministry of Science and Higher Education, and private donors.

[ B K K ]

CONTACTS:
Alex Wolszczan: alex@astro.psu.edu, (+1) 814-863-1756
Lawrence Ramsey: lramsey@astro.psu.edu, (+1)814-865-0410
Barbara Kennedy (PIO): science@psu.edu, (+1) 814-863-4682

____________________________________________________


ABOUT THE HOBBY-EBERLY TELESCOPE

The William P. Hobby-Robert E. Eberly Telescope is one of the largest and most powerful telescopes in the world. It was conceived by Lawrence Ramsey, department head and professor of astronomy and astrophysics at Penn State, and Daniel W. Weedman, formerly a professor of astronomy and astrophysics at Penn State. The Hobby-Eberly Telescope is located in a remote area of West Texas at the McDonald Observatory, which has the darkest skies of any major observatory in the continental United States. The namesakes of the Hobby-Eberly Telescope are William P. Hobby, the former Lieutenant Governor of Texas, and Robert E. Eberly of Pennsylvania, an industrialist and philanthropist. The Hobby-Eberly Telescope is a joint project of The University of Texas at Austin, Penn State University, Stanford University, Ludwig-Maximilians-Universität München and Georg-August-Unversität Göttingen.


Source: PSU Press Release

The Lowell Observatory press release is reproduced below:

FOR IMMEDIATE RELEASE
August 6, 2007

Flagstaff, Ariz.– An international team of astronomers with the Trans-atlantic Exoplanet Survey announce today the discovery of TrES-4, a new extrasolar planet in the constellation of Hercules. The new planet was identified by astronomers looking for transiting planets – that is, planets that pass in front of their home star – using a network of small automated telescopes in Arizona, California, and the Canary Islands. TrES-4 was discovered less than half a degree (about the size of the full Moon) from the team’s third planet, TrES-3.

"TrES-4 is the largest known exoplanet," said Georgi Mandushev, Lowell Observatory astronomer and the lead author of the paper announcing the discovery. "It is about 70 percent bigger than Jupiter, the Solar System’s largest planet, but less massive, making it a planet of extremely low density. Its mean density is only about 0.2 grams per cubic centimeter, or about the density of balsa wood! And because of the planet’s relatively weak pull on its upper atmosphere, some of the atmosphere probably escapes in a comet-like tail."

The new planet TrES-4 was first noticed by Lowell Observatory's Planet Search Survey Telescope (PSST), set up and operated by Edward Dunham and Georgi Mandushev. The Sleuth telescope, maintained by David Charbonneau (CfA) and Francis O'Donovan (Caltech), at Caltech's Palomar Observatory also observed transits of TrES-4, confirming the initial detections. TrES-4 is about 1400 light years away and orbits its host star in three and a half days. Being only about 4.5 million miles from its home star, the planet is also very hot, about 1,600 Kelvin or 2,300 degrees Fahrenheit.

"TrES-4 appears to be something of a theoretical problem,” said Edward Dunham, Lowell Observatory Instrument Scientist. "It is larger relative to its mass than current models of superheated giant planets can presently explain. Problems are good, though, since we learn new things by solving them."

“We continue to be surprised by how relatively large these giant planets can be,” adds Francis O’Donovan, a graduate student in astronomy at the California Institute of Technology who operates one of the TrES telescopes. “ But if we can explain the sizes of these bloated planets in their harsh environments, it may help us understand better our own Solar System planets and their formation.”

By definition, a transiting planet passes directly between the Earth and the star, blocking some of the star’s light and causing a slight drop in its brightness. To look for transits, the small telescopes are automated to take wide-field timed exposures of the clear skies on as many nights as possible. When observations are completed for a particular field – usually over an approximate two-month period – astronomers measure very precisely the light from every star in the field in order to detect the possible signature of a transiting planet. "TrES-4 blocks off about one percent of the light of the star as it passes in front of it," said Mandushev. "With our telescopes and observing techniques, we can measure this tiny drop in the star's brightness and deduce the presence of a planet there."

Not only is the planet TrES-4 mysterious and intriguing, but so is its host star cataloged as GSC 02620-00648. Georgi Mandushev explains: “The host star of TrES-4 appears to be about the same age as our Sun, but because it is more massive, it has evolved much faster. It has become what astronomers call a ‘subgiant’, or a star that has exhausted all of its hydrogen fuel in the core and is on its way of becoming a ‘red giant’, a huge, cool red star like Arcturus or Aldebaran.”

In order to help confirm they had found a planet, Gáspár Bakos of the Hungarian Automated Telescope Network (HATNet) and Harvard's Guillermo Torres switched from the 10-centimeter TrES telescopes to one of the 10-meter telescopes at the W. M. Keck Observatory on the summit of Mauna Kea, Hawaii. Using this giant telescope, they confirmed that the TrES team had indeed found a new planet. In order to measure accurately the size and other properties of TrES-4, astronomers also made follow up observations with bigger telescopes at Lowell Observatory and Fred L. Whipple Observatory in Arizona.

The authors of the paper "TrES-4: A Transiting Hot Jupiter of Very Low Density", accepted for publication in the Astrophysical Journal, are: Georgi Mandushev and Edward Dunham of Lowell Observatory; Francis T. O’Donovan and Lynne Hillenbrand of the California Institute of Technology; David Charbonneau, Guillermo Torres, David Latham, Gáspár Bakos, Alessandro Sozzetti, and José Fernández of the Harvard-Smithsonian Center for Astrophysics; Mark Everett and Gilbert Esquerdo of the Planetary Science Institute; Markus Rabus and Juan Belmonte of Instituto de Astrofísica de Canarias in Tenerife, Spain; and Timothy Brown of the Las Cumbres Observatory Global Telescope. Download a preprint of the paper here.

This research is funded by NASA through the Origins of Solar Systems Program.

A computer-generated simulation of TrES-4, with its host star on the right. The planet's home star is bigger and hotter than the Sun, and is about ten times larger than the planet. Astronomers speculate that the large size and low density of TrES-4 may cause a small fraction of its outer atmosphere to escape from the planet’s gravitational pull and form an envelope, or a comet-like tail around the planet.
Credit: Jeffrey Hall, Lowell Observatory.


FOR MORE INFORMATION

Description of the TrES Network

end

About Lowell Observatory

Lowell Observatory is a private, non-profit research institution founded in 1894 by Percival Lowell. The Observatory has been the site of many important findings including the discovery of the large recessional velocities (redshift) of galaxies by Vesto Slipher in 1912-1914 (a result that led ultimately to the realization the universe is expanding), and the discovery of Pluto by Clyde Tombaugh in 1930. Today, Lowell's 19 astronomers use ground-based telescopes around the world, telescopes in space, and NASA planetary spacecraft to conduct research in diverse areas of astronomy and planetary science. The Observatory welcomes 70,000 visitors each year to its Mars Hill campus in Flagstaff, Arizona for a variety of tours, telescope viewing, and special programs. Lowell Observatory currently has four research telescopes at its Anderson Mesa dark sky site east of Flagstaff, and is building a 4-meter class research telescope, the Discovery Channel Telescope, in partnership with Discovery Communications.

CONTACT

Steele Wotkyns
(928) 233-3232
steele@lowell.edu

Source: Lowell Observatory Press Release

The California Institute of Technology press release is reproduced below:

August 6 2007

PASADENA, Calif.--An international team of astronomers has discovered the largest-radius and lowest-density exoplanet of all those whose mass and radius are known. It is a gas-giant planet about twice the size of Jupiter, and is likely to have a curved cometlike tail. It has been named TrES-4, to indicate that it is the fourth planet detected by the Trans-atlantic Exoplanet Survey (TrES) network of telescopes.

TrES-4 is in the constellation Hercules and is the 19th transiting planet discovered so far. It orbits the star catalogued as GSC02620-00648, which is about 440 parsecs (1,435 light-years) away from Earth.

A transiting planet is one that passes directly in front of its host star as seen from Earth. When a transiting planet passes between its star and Earth, the planet blocks some of the light from the star in a manner similar to that caused by the moon's passing between the sun and Earth during a solar eclipse. In the case of TrES-4, this reduces the starlight by one percent, a tiny, yet detectable, effect.

TrES-4 is noteworthy for having a radius 1.67 times that of Jupiter, yet a mass only 0.84 times Jupiter's, resulting in an extremely low density of 0.222 g cm-3. In comparison, Jupiter has a density of 1.3 g cm-3. The density of TrES-4 is so low that the planet would float on water.

"We continue to be surprised by how relatively large these giant planets can be", says Francis O'Donovan, a graduate student in astronomy at the California Institute of Technology who operates one of the TrES telescopes. "But if we can explain the sizes of these bloated planets in their harsh environments, it may help us better understand our own solar system's planets and their formation."

The study's lead author, Georgi Mandushev of Lowell Observatory in Arizona, noted the challenges such big planets present for theories of planet formation and evolution: "This find presents a new puzzle for astronomers who model the structure and atmospheres of giant planets. It highlights the diversity of physical properties among giant planets around other stars and indicates that we can expect more discoveries of unusual and enigmatic exoplanets in the near future."

TrES is a global network of three small telescopes utilizing mostly amateur-astronomy components and off-the-shelf four-inch camera lenses: Sleuth telescope at Caltech's Palomar Observatory in San Diego County; the Planet Search Survey Telescope (PSST) at Lowell Observatory; and the STellar Astrophysics and Research on Exoplanets (STARE) telescope in the Canary Islands.

Planet TrES-4 makes a complete revolution around its parent star every 3.55 days, so a year on this planet is shorter than a week on Earth. The planet is about seven million kilometers away from its star--over ten times closer than Mercury is to the Sun--and so it is heated by the intense starlight to about 1600 degrees Kelvin (about 2300 degrees Fahrenheit).

In terms of mass and distance to its sun, TrES-4 is similar to HD209458b, and like that planet, it may have an extended outer atmosphere. Astronomers hypothesize that the outer atmospheric layers may be able to escape the planet's gravity and form a curved cometlike tail.

To look for transits, the small telescopes are automated to take wide-field timed exposures of the clear skies on as many nights as possible. When an observing run is completed for a particular field--usually over an approximately two-month period--the data are run through software that corrects for various sources of distortion and noise.

The end result is a "light curve" for each of the thousands of stars in the field. If the software detects regular variations in the light curve for an individual star, then the astronomers do additional work to see if the source of the variation is indeed a transiting planet. One possible alternative is that the object passing in front of the star is another star, fainter and smaller.

In order to accurately measure the size and other properties of TrES-4, astronomers used the 0.8-meters telescope at Lowell Observatory, the 1.2-meter telescope at the Whipple Observatory (both in Arizona) and the 10-meter Keck Telescope in Hawaii.

Observations were carried out from September 2006 to April 2007.

The paper about the discovery of this extrasolar planet, "TrES-4: A Transiting Hot Jupiter of Very Low Density," has been accepted for publication by the Astrophysical Journal.

The paper's authors are Georgi Mandushev and Edward Dunham of Lowell Observatory; Francis O'Donovan, a graduate student at Caltech; Lynne Hillenbrand, an associate professor of astronomy at Caltech; David Charbonneau (Alfred P. Sloan Research Fellow), Guillermo Torres, David W. Latham, Gáspár Bakos (Hubble Fellow), Alessandro Sozzetti, José Fernández and Guilbert Esquerdo of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; Mark Everett of the Planetary Science Institute in Tucson, Arizona; Timothy Brown of Las Cumbres Observatory Global Telescope Network; and Markus Rabus and Juan A. Belmonte of the Instituto de Astrofísica de Canarias in Tenerife, Spain.

This research is funded by NASA through its Origins program. The paper is available online at http://arxiv.org/.

Contact: Robert Tindol (626) 395-3631 tindol@caltech.edu

Source: CalTech Press Release

The UCLA press release is reproduced below:

Date: August 16, 2007
Contact: Stuart Wolpert ( swolpert@support.ucla.edu )
Phone: 310-206-0511

The chemical fingerprint of a burned-out star indicates that Earth-like planets may not be rare in the universe and could give clues to what our solar system will look like when our sun dies and becomes a white dwarf star some five billion years from now.

Astronomers from UCLA report that a white dwarf star known as GD 362, which is surrounded by dusty rings similar to those of Saturn, has been contaminated by a large asteroid that left more than a dozen observable chemical elements in the white dwarf's atmosphere. Such an observation is unprecedented in astronomy. Was there some kind of violent interaction between the star and the asteroid?

The UCLA astronomers think that after about a billion years orbiting the white dwarf as part of an ancient planetary system, an asteroid got close enough to the star to be torn apart by its very strong gravitational force field. An Earth-sized but exceedingly dense white dwarf is the standard end state for most stars. This particular white dwarf, which is under investigation by the W.M. Keck Observatory in Hawaii, is located in the constellation Hercules, approximately 150 light-years, or 1,000 trillion miles, from Earth.

The asteroid broke apart into dust particles that orbited the white dwarf and over time "polluted the white dwarf's atmosphere," said Benjamin Zuckerman, UCLA professor of physics and astronomy and lead author of the research, which has been accepted for publication in an upcoming issue of the Astrophysical Journal, the premier journal of astronomy.

The astronomers note that the spectroscopic observations they are reporting constitute the first detailed assessment of the elemental composition of an object in an extrasolar planetary system.

"The relative abundance of the elements in the white dwarf's atmosphere, polluted by the asteroid, appears similar to those in our Earth-Moon system," Zuckerman said.

"What we have here is a composition of the white dwarf that is fairly similar to that of the inner planets of our solar system," said Michael Jura, UCLA professor of physics and astronomy and co-author of the research. "Are there other terrestrial planets like Earth in other solar systems? This white dwarf's fingerprint is a significant advance in demonstrating that something like terrestrial planet formation occurred around this other star and probably occurred around other stars as well, because it suggests the Earth's composition is not unique.

"The asteroid that is being shredded is very iron-rich and abundant in calcium and other elements, and low in carbon, like a sturdy rock," Jura added.

The research implies that the forces that made the Earth and our inner solar system seem to have occurred in this system as well, and probably around other white dwarfs too, Jura said.

Zuckerman said the research result does not rule out the possibility that two planets in this ancient planetary system collided and the orbiting dust and detected elements are from a piece of one of the colliding planets rather than from a more conventional asteroid.

"Something dramatic and violent probably happened," he said.

What knocked the asteroid out of its original orbit? It probably was deflected by the gravitational field of a large planet, Zuckerman said.

Our own planetary system looks very stable, Zuckerman said, but billions of years from now, when the sun starts to expand in size and lose mass rapidly, the planets and asteroids will spiral away, and the planets closest to the sun, like Mercury and Venus, will be engulfed by the sun and destroyed.

"But other planets, probably including the Earth and the asteroid belt between Mars and Jupiter will spiral out, and their orbits then will make our stable system much less stable," he said.

A third UCLA author on the paper, physics and astronomy associate professor Brad Hansen, said, "In our solar system, objects rich in iron formed closer to the sun than the objects rich in carbon and ice, which formed farther away, where it is colder. This research tells us about the origin of the asteroid, its temperature when it formed and its chemistry — conditions similar to the Earth's."

The group of astronomers, which also includes of UCLA graduate student Carl Melis and Detlev Koester at Germany's University of Kiel, detected 17 elements in the atmosphere of the white dwarf that probably came from a large asteroid; the asteroid may have once been part of a larger body, perhaps like one of the inner planets of our solar system. Many of the elements have never before been detected in the atmosphere of a white dwarf, including the rare elements strontium and scandium.

The gravitational field of the white dwarf is so strong that all elements heavier than the lightest elements — hydrogen and helium — quickly sink into the white dwarf's interior, Hansen said.

The asteroid likely broke up more than 100,000 years ago, and perhaps as long as a million years ago, the astronomers said. The star became a very hot white dwarf approximately 1 billion years ago and since then has been steadily cooling off.

Unlike GD 362, most white dwarfs are pristine in their composition.

"You wouldn't notice another skyscraper in New York, but the same skyscraper in Nebraska would stick out like a sore thumb," Hansen said. "That's the case here. A little change in the atmosphere of a white dwarf is very obvious."

The astronomers used the HIRES spectrometer on the Keck I Telescope to take optical spectra of the white dwarf, spanning the ultraviolet to the full visible range of light. Each element can be identified by its own characteristic spectrum.

The researchers said they find it quite remarkable that even at a distance of 1,000 trillion miles, the Keck HIRES measurements enable them to determine minute details of the bulk composition of a relatively tiny object — as astronomical sizes go — like an asteroid. Currently, no other known observational technique exists that allows for such compositional information to be obtained.

The remains of a white dwarf cool slowly over many billions of years as the dying ember makes its slow journey into oblivion.

NASA funded the research.

UCLA is California's largest university, with an enrollment of nearly 37,000 undergraduate and graduate students. The UCLA College of Letters and Science and the university's 11 professional schools feature renowned faculty and offer more than 300 degree programs and majors. UCLA is a national and international leader in the breadth and quality of its academic, research, health care, cultural, continuing education and athletic programs. Four alumni and five faculty have been awarded the Nobel Prize.

-UCLA-

SW353

Source: UCLA press release

August 18
Astronomers studied a white dwarf called GD 362 located 150 light-years away in our Milky Way galaxy.

They figured out the chemical composition of a large asteroid that was ripped apart by gravitational forces as it approached GD 362, finding it was similar to the Earth's crust.

It was rich in iron and calcium and low in carbon, much like a strong rock, they said.

The white dwarf is surrounded by dusty rings, probably made up of objects shredded as they ventured too close.

GD 362 once was a star similar to the sun.

After billions of years, it ballooned into a "red giant" as part of its death process, expelling most of its outer material, then degenerated into a burnt-out remnant called a white dwarf.

The fact that the asteroid is so similar in make-up to the Earth, as well as the moon, indicates that rocky planets like our own may have orbited the star eons ago.

The rocky asteroid had a diameter of roughly 200 km and may have been smashed by GD 362 between 100,000 and a million years ago.

While the white dwarf has a mass close to that of our sun, it has collapsed to such a point that its diameter is approximately that of the Earth.

GD 362 may offer a glimpse into our solar system's future. Astronomers believe the sun in perhaps 5 billion years will go through the same process, ending up as a white dwarf.
go

wow.. that's too sad.. we have seen thy future.. oh what the heck that's my grandson's x10000000 problem.

The University of Delaware press release is reproduced below:

1:12 p.m., Sept. 12, 2007--A large team of astronomers, including scientists from the University of Delaware and Mt. Cuba Observatory, has announced that at least one planet in the universe has survived the violent events that accompany the late stages of a star's life cycle.

Roberto Silvotti of the Italian National Institute of Astrophysics led the team, which discovered a planet slightly more massive than Jupiter around the star V 391 Pegasi.

The planet orbits this star every 3.2 years, traveling 158 million miles away from the star. It follows an orbit slightly larger than the orbit of Mars. This discovery will be published Sept. 13 in the British journal Nature.

This image represents the system V 391 Pegasi as it was about 100 million years ago, when the star was at its maximum red giant expansion and close to explosive helium ignition, the so-called 'helium flash', that causes the expulsion of the star's outer layers. At that time, the stellar radius of about 100 million kilometers was not much smaller than the orbital distance of the planet, of the order of 150 million kilometers (i.e. the distance between the Earth and the Sun). (Image courtesy of HELAS, the European Helio- and Asteroseismology Network, funded by the European Union under Framework Programme 6; Mark Garlick, artist.)

Harry Shipman, Annie Jump Cannon Professor of Astronomy at UD and a member of the team, said the discovery is extremely important. “With 250 planets out there, why is this one interesting? It is the first planet discovered around a star late in its life cycle. This star has previously been a red giant star, which according to conventional wisdom is a planet-eater,” he said. “Also, it is the first planet discovered using a new technique.”

Shipman said that 100 million years ago, V 391 Pegasi was a kind of star known as a red giant. Its surface swelled up to an enormous size, where it would definitely engulf planets like Venus and Mercury, were such planets to be orbiting V 391 Pegasi. Until this discovery, astronomers argued vigorously whether planets like Earth and Mars could survive when the sun becomes a red giant.

Jonathan Fortney of NASA's Ames Research Center in California wrote that “the planet found by Roberto Silvotti and colleagues demonstrates that planets with orbits similar to the Earth's can survive the red-giant expansion phase of their parent star." Fortney prepared a companion piece in Nature's "News and Views" section, which highlights particularly important discoveries.

The observations which led to the discovery of this important planet were obtained, to a great extent, from a collaboration called the Whole Earth Telescope, Shipman said.

The team that discovered it consists of many astronomers from 15 separate countries around the world, all of whom observed this star at the same time in 2003 and some of whom continued to observe the star over the past three years. This team now operates under the leadership of Judi Provencal and Susan Thompson, research associates in UD's Department of Physics and Astronomy, and Shipman. All are astronomers at Mt. Cuba Observatory and UD.



This planet discovery also marks the first successful use of a new technique used to discover planets orbiting distant stars. The vast majority of prior planet hunters spread the light of stars out into a million rainbow colors and looked for very subtle shifts in the wavelength, or color, of features in this rainbow-like pattern, or spectrum, of starlight.

Silvotti and his team measured small variations in the light from V 391 Pegasi and found that these light variations came from a highly accurate clock. When the star moves towards the earth, clock pulses are bunched together and arrive more rapidly. When they move away from the earth, they arrive more slowly. The changing arrival times of ticks from these stellar clocks provide indications of the motion of the star as its motion is disturbed by an unseen object.

Three years worth of observations of V 391 Pegasi showed the results of the star's motion back and forth because of the presence of its planet.

The Whole Earth Telescope team has cooperatively observed a variety of types of stars for nearly 20 years. It was founded at the University of Texas and until a few years ago, leadership groups at Texas or at Iowa State University coordinated the team's efforts.

For the past few years, the team's work has been part of the program of the Delaware Asteroseismic Research Center, a unit established at the Mt. Cuba Astronomical Observatory in close collaboration with UD.

"Many of us had hoped that we would find a planet, because the kind of careful measurements we make of these varying stars were just the thing that was needed. It's great to see one at last," Shipman said

Source: UD press release

The Iowa State University press release is reproduced below:

9-12-07



Contacts:
Steve Kawaler, Physics and Astronomy, (515) 294-9728, sdk@iastate.edu

Roberto Silvotti, INAF-Osservatorio Astronomico di Capodimonte, +39/331/4063556, silvotti@na.astro.it

Mike Krapfl, News Service, (515) 294-4917, mkrapfl@iastate.edu

Iowa State astronomer helps discover planet that offers clues to Earth's future

AMES, Iowa -- An international team of astronomers that includes Steve Kawaler of Iowa State University has announced the first discovery of a planet orbiting a star near the end of its life.

The announcement, culminating seven years of research, will be published in the Sept. 13 issue of the journal Nature.

The news provides a preliminary picture of what could be the Earth's destiny in four to five billion years. That's when the sun will exhaust its hydrogen fuel, expand enormously as a red giant and expel its outer layers in an explosive helium flash.

The planet discovered by the researchers, "V 391 Pegasi b," has survived all those changes to its sun.

The international research team was led by Roberto Silvotti from the INAF-Osservatorio Astronomico di Capodimonte in Naples, Italy. They discovered the planet orbiting "V 391 Pegasi," a faint star in the constellation of Pegasus.

"The exciting thing about finding a planet around this star is that it indicates that planetary systems can survive the giant phase and the helium flash of their parent star," said Kawaler, an Iowa State professor of physics and astronomy. "It bodes well for the survival of our own Earth in the distant future. Before V 391 Pegasi lost its outer regions at the helium flash, the planet orbited the star at about the same distance that the Earth orbits our sun."

But, Kawaler said, "We shouldn't take too much heart in this -- this planet is larger than Jupiter, so a smaller planet like the Earth could still be vulnerable."

Kawaler helped the 23-member research team make its discovery by coordinating observations during a 2003 run of the Whole Earth Telescope. Iowa State is a lead institution in the Whole Earth Telescope, a worldwide network of cooperating observatories that allow astronomers to take uninterrupted measurements of variable stars that change in brightness. The discovery of V 391 Pegasi b was made by detailed measurements of the clocklike variation of the star caused by the planet tugging on it.

Kawaler also advanced the project by doing theoretical calculations to make sure irregularities of the star's orbital motion were caused by the orbiting planet.

The astronomers found that at the present time, V 391 Pegasi b has an orbital distance 1.7 times the medium distance between the Earth and the sun. As stars age and reach their red giant phase, they undergo an enormous expansion (with their volume increasing by a factor of millions) that can easily reach and engulf their inner planets.

"The same will happen to the sun," Silvotti said. "As far as our planets are concerned, we expect Mercury and Venus to disappear in the sun's envelope, whereas Mars should survive. The fate of the Earth is less clear because its position is really at the limit: it appears more likely that the Earth will not survive the red giant expansion of the sun either, but it is not for sure."

As is the case for almost all planets beyond our solar system, V 391 Pegasi b cannot be seen directly. Silvotti said it took seven years of observations and calculations to confirm the existence of the planet.

-30-

Source: ISU press release

In the Star Wars movies fictional planets are covered with forests, oceans, deserts, and volcanoes. But new models from a team of MIT, NASA, and Carnegie scientists begin to describe an even wider range of Earth-size planets that astronomers might actually be able to find in the near future.


Image above: This is an artist's concept of an Earthlike planet
around another star.
Credit: NASA JPL

Sara Seager, Massachusetts Institute of Technology, Cambridge, Mass.; Marc Kuchner, NASA Goddard Space Flight Center, Greenbelt, Md.; Catherine Hier-Majumder, Carnegie Institution of Washington, (deceased); and Burkhard Militzer, Carnegie, have created models for 14 different types of solid planets that might exist in our galaxy. The 14 types have various compositions, and the team calculated how large each planet would be for a given mass. Some are pure water ice, carbon, iron, silicate, carbon monoxide, and silicon carbide; others are mixtures of these various compounds.

"We’re thinking seriously about the different kinds of roughly Earth-size planets that might be out there, like George Lucas, but for real," says Kuchner.

The team took a different approach from previous studies. Rather than assume that planets around other stars are scaled-up or scaled-down versions of the planets in our solar system, they considered all types of planets that might be possible, given what astronomers know about the composition of protoplanetary disks around young stars.

"We have learned that extrasolar giant planets often differ tremendously from the worlds in our solar system, so we let our imaginations run wild and tried to cover all the bases with our models of smaller planets," says Kuchner. "We can make educated guesses about where these different kinds of planets might be found. For example, carbon planets and carbon-monoxide planets might favor evolved stars such as white dwarfs and pulsars, or they might form in carbon-rich disks like the one around the star Beta Pictoris. But ultimately, we need observations to give us the answers."


Image above: Astronomers have calculated the diameters of various
types of planets given certain compositions and masses. This image
shows the relative sizes of six different kinds of planets with
different compositions, and depending on whether they have the
same mass as Earth, or five times the mass of Earth. Note that
the 5-Earth-mass planets are larger than their 1-Earth-mass
counterparts, but they are not five times larger due to the
gravitational compression that occurs when a planet's mass is
increased. The planets are shown silhouetted against the Sun,
as if they are transiting planets seen from afar.
Credit: Marc Kuchner/NASA GSFC.

The team calculated how gravity would compress planets of varying compositions. The resulting computer models predict a planet’s diameter for a given composition and mass. For example, a 1-Earth-mass planet made of pure water will be about 9,500 miles across, whereas an iron planet with the same mass will be only about 3,000 miles in diameter. For comparison, Earth, which is made mostly of silicates, is 7,926 miles across at its equator.

Some of the results were expected, such as the fact that pure water planets (similar to the moons of the outer planets in our solar system, which consist mostly of water ice) were the least dense of the solid planets, and pure iron planets are the most dense. But there were some surprises. The team discovered that no matter what material a planet is made of, the mass/diameter relationship follows a similar pattern.

"All materials compress in a similar way because of the structure of solids," explains Seager. "If you squeeze a rock, nothing much happens until you reach some critical pressure, then it crushes. Planets behave the same way, but they react at different pressures depending on the composition. This is a big step forward in our fundamental understanding of planets."


Image above: These theoretical models plot a planet's size and
mass given a certain composition. Future observations might be
able to distinguish a pure water planet from a pure iron planet,
but might have difficulty distinguishing a carbon planet from a
silicate planet, for example.
Credit: Marc Kuchner/NASA GSFC.

The team hopes that these models will yield insights into planet compositions when astronomers start finding Earth-sized planets around other stars. Missions such as the French Corot satellite, which launched on December 27, 2006, and NASA’s Kepler spacecraft, scheduled to launch in 2009, can find planets not much larger than Earth by watching them pass in front of their host stars, events known as transits. The transits yield the planet’s size, and follow-up studies can measure the mass. By comparing a planet's size and mass, astronomers might be able to determine whether it is mostly water ice or mostly iron, for example.

But astronomers using the transit method will find it difficult at best to distinguish a silicate planet from a carbon planet, because they’re about the same size for a given mass. "To make this finer distinction, we will need some help from NASA’s James Webb Space Telescope or Terrestrial Planet Finder," says Kuchner. "With these instruments, we could take spectra of Earth-mass planets, which will tell us about their chemistries."

The team’s paper is currently scheduled to appear in the October 20 issue of the Astrophysical Journal.


Bob Naeye
Goddard Space Flight Center

Source: NASA/GSFC - News

The University of Rochester press release is reproduced below:

MEDIA CONTACT: Jonathan Sherwood (585) 273-4726, jonathan.sherwood@rochester.edu

October 1, 2007

Astronomers at the University of Rochester are pointing to three nearby stars they say may hold "embryonic planets"—a missing link in planet-formation theories.

As scientists try to piece together how our own planet came to be, they look to the forming planets of other star systems for clues. But astronomers have been unable to find evidence for one of the key stages of planet development, a period early in the planet's formation when it is only as large as tiny Pluto.

In an attempt to reveal this hidden phase of a planet's life, Alice Quillen, associate professor of astronomy at the University of Rochester, employed new Hubble Space Telescope imagery to measure the thickness of the dust disks that surround forming stars, and to calculate the size of the planets growing within.

The results help paint a picture of a planet's earliest years, and tell us how our own small planet probably began its life, says Quillen.

Scientists have inferred the presence of nearly 250 planets in the last decade, but Quillen's method focuses on a unique aspect: the proto-planetary disk's thickness.

PHOTOS


AU Microscopii from the Hubble Space Telescope (credit NASA)


Fomalhaut from the Hubble Space Telescope (credit NASA)


Beta Pictoris from the Hubble Space Telescope (credit NASA)


Alice Quillen, associate professor in the Department of Physics & Astronomy

Quillen explains that a disk of gritty dust usually surrounds forming stars, and provides the raw material for planet building. The cloud of dust thins as the system ages, but if enough dust has clumped together, the "embryonic planet," as Quillen calls it, will knock the dust and grit into ever-more eccentric orbits. Over time, this will cause an otherwise razor-thin disk to appear puffed up.

"We're able to determine for the first time how large the bodies must be in a disk to scatter the dust the way we've observed," says Quillen, one of the world's leading experts on the interaction between planets and stellar dust disks.

Using new Hubble images, Quillen measured the "puffiness" of AU Microscopii, Beta Pictoris, and Fomalhaut—three nearby stars with young disks positioned edge-on toward Earth. All three stars displayed a thicker disk than conventional models anticipated, so Quillen stepped beyond those models.

Dust disks have a lifespan determined by a balance of how quickly the solar wind blows the dust away, and how quickly the largest "grit clumps" replenish the dust through their collisions, says Quillen. Based on this balance, the size and age of a disk reveal how large the clumps inside must be.

But the conventional theory doesn't take a disk's thickness into account because until the Hubble images, astronomers had no way to measure it. Thus, the largest "clump" the model could predict was about a kilometer wide—a far cry from the fully grown planets that emerge from such disks.

Armed with the new images and her own models of dust dynamics, Quillen estimated how much mass was required to gravitationally scatter the dust to the thicknesses she observed.

"Those calculations pushed us into Pluto-sized bodies," says Quillen. At roughly 1,000 kilometers in size—and owing to Pluto's recent demotion from planethood—Quillen dubbed these new bodies, embryonic planets.

Quillen is now looking for more young star systems to investigate with her model, but the criteria for candidates is quite strict. The systems have to be young enough to still have their protostellar disks, but old enough to be forming the embryonic planets. The systems must also appear edge-on from Earth and be near enough that Hubble can accurately discern the thickness of their disks. At the moment, the three stars Quillen has already observed appear to be the only candidates that meet all the standards.

This research was funded in part by the National Science Foundation.


About the University of Rochester

The University of Rochester (www.rochester.edu) is one of the nation's leading private universities. Located in Rochester, N.Y., the University gives students exceptional opportunities for interdisciplinary study and close collaboration with faculty through its unique cluster-based curriculum. Its College of Arts, Sciences, and Engineering is complemented by the Eastman School of Music, Simon School of Business, Warner School of Education, Laboratory for Laser Energetics, Schools of Medicine and Nursing, and the Memorial Art Gallery.

Source: University of Rochester Press Release

The Johns Hopkins University Applied Physics Laboratory press release is reproduced below:

For Immediate Release
October 3, 2007

Media Contact
Mike Buckley
Phone: (240) 228-7536 or (443) 778-7536
E-mail: michael.buckley@jhuapl.edu

Science Contact
Mike Buckley
Phone: (240) 228-7536 or (443) 778-7536
E-mail: michael.buckley@jhuapl.edu


Credit: NASA/JPL-Caltech/JHUAPL

An Earth-like planet is likely forming 424 light-years away in a star system called HD 113766, say astronomers using NASA's Spitzer Space Telescope.

Scientists have discovered a huge belt of warm dust – enough to build a Mars-size planet or larger – swirling around a distant star that is just slightly more massive than our sun. The dust belt, which they suspect is clumping together into planets, is located in the middle of the system's terrestrial habitable zone. This is the region around a star where liquid water could exist on any rocky planets that might form. Earth is located in the middle of our sun's terrestrial habitable zone.

At approximately 10 million years old, the star is also at just the right age for forming rocky planets.

"The timing for this system to be building an Earth is very good," says Dr. Carey Lisse, of the Johns Hopkins University Applied Physics Laboratory, Laurel, Md. "If the system was too young, its planet-forming disk would be full of gas, and it would be making gas-giant planets like Jupiter instead. If the system was too old, then dust aggregation or clumping would have already occurred and all the system's rocky planets would have already formed."

According to Lisse, the conditions for forming an Earth-like planet are more than just being in the right place at the right time and around the right star – it's also about the right mix of dusty materials.

Using Spitzer's infrared spectrometer instrument, he determined that the material in HD 113766 is more processed than the snowball-like stuff that makes up infant solar systems and comets, which are considered cosmic "refrigerators" because they contain pristine ingredients from the early solar system. However, it is also not as processed as the stuff found in mature planets and the largest asteroids. This means the dust belt must be in a transitional phase, when rocky planets are just beginning to form.

How do scientists know the material is more processed than that of comets? From missions like NASA's Deep Impact – in which an 820-pound impactor spacecraft collided with comet Tempel 1 – scientists know that early star systems contain a lot of fragile organic material. That material includes polycyclic aromatic hydrocarbons (carbon-based molecules found on charred barbeque grills and automobile exhaust on Earth), water ice, and carbonates (chalk). Lisse says that HD 113766 does not contain any water ice, carbonates or fragile organic materials.

From meteorite studies on Earth, scientists also have a good idea of what makes up asteroids – the more processed rocky leftovers of planet formation. These studies tell us that metals began separating from rocks in Earth's early days, when the planet's body was completely molten. During this time, almost all the heavy metals fell to Earth's center in a process called "differentiation." Lisse says that, unlike planets and asteroids, the metals in HD 113766 have not totally separated from the rocky material, suggesting that rocky planets have not yet formed.

"The material mix in this belt is most reminiscent of the stuff found in lava flows on Earth. I thought of Mauna Kea material when I first saw the dust composition in this system – it contains raw rock and is abundant in iron sulfides, which are similar to fool's gold," says Lisse, referring to a well-known Hawaiian volcano.

"It is fantastic to think we are able to detect the process of terrestrial planet formation. Stay tuned — I expect lots more fireworks as the planet in HD113766 grows," he adds.

Lisse has written a paper (Click here to read Lisse's paper, Circumstellar Dust Created by Terrestrial Planet Formation in HD 113766) on his research that will be published in an upcoming issue of Astrophysical Journal; he will also present his findings next week at the American Astronomical Society Division for Planetary Sciences meeting in Orlando, Fla. Lisse's research was funded through a Johns Hopkins Applied Physics Laboratory Stuart S. Janney Fellowship and a Spitzer Space Telescope guest observer grant.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA.

The University of Maryland is responsible for overall Deep Impact mission science, and project management is handled by JPL.

The Applied Physics Laboratory (APL) is a not-for-profit laboratory and division of The Johns Hopkins University. APL conducts research and development primarily for national security and for nondefense projects of national and global significance. APL is located midway between Baltimore and Washington, D.C., in Laurel, Md. For information, visit www.jhuapl.edu.

Source: JHUAPL Press Release

An artist concept of HD 113766
NASA/JPL-Caltech/C. Lisse
(Johns Hopkins University Applied Physics
Laboratory)

Written by Linda Vu, Spitzer Science Center
October 3, 2007

An Earth-like planet is likely forming 424 light-years away in a star system called HD 113766, say astronomers using NASA's Spitzer Space Telescope.

Scientists have discovered a huge belt of warm dust -- enough to build a Mars-size planet or larger -- swirling around a distant star that is just slightly more massive than our Sun. The dust belt, which they suspect is clumping together into planets, is located in the middle of the system's terrestrial habitable zone. This is the region around a star where liquid water could exist on any rocky planets that might form. Earth is located in the middle of our Sun's terrestrial habitable zone.

At approximately 10 million years old, the star is also at just the right age for forming rocky planets.

"The timing for this system to be building an Earth is very good," said Dr. Carey Lisse, of the Johns Hopkins University Applied Physics Laboratory, Baltimore, Md. "If the system was too young, its planet-forming disk would be full of gas, and it would be making gas-giant planets like Jupiter instead. If the system was too old, then dust aggregation or clumping would have already occurred and all the system's rocky planets would have already formed."
The Right Stuff

According to Lisse, the conditions for forming an Earth-like planet are more than just being in the right place at the right time and around the right star -- it's also about the right mix of dusty materials.

Using Spitzer's Infrared Spectrometer instrument, he determined that the material in HD 113866 is more processed than the snowball-like stuff that makes up infant solar systems and comets, which are considered "cosmic refrigerators" because they contain pristine ingredients from the early solar system. However, it is also not as processed as the stuff found in mature planets and asteroids. This means the dust belt must be in a transitional phase, when rocky planets are just beginning to form.

How do scientists know the material is more processed than that of comets? From missions like NASA's Deep Impact -- where an 820-pound impactor spacecraft that collided with Comet Tempel 1 -- scientists know that early star systems contain a lot of fragile organic material. That material includes polycyclic aromatic hydrocarbons (carbon-based molecules found on charred barbeque grills and automobile exhaust on Earth), water ice, and carbonates (chalk). Lisse says that HD 113766 does not contain any water ice, carbonates, or fragile organic materials.

From meteorite studies on Earth, scientists also have a good idea of what makes up asteroids -- the more processed rocky leftovers of planet formation. These studies tell us that metals began separating from rocks in Earth's early days, when the planet's body was completely molten. During this time, almost all the heavy metals fell to Earth's center in a process called "differentiation." Lisse says that, unlike planets and asteroids, the metals in HD 113766 have not totally separated from the rocky material, suggesting that rocky planets have not yet formed.

"The material mix in this belt is most reminiscent of the stuff found in lava flows on Earth. I thought of Mauna Kea material when I first saw the dust composition in this system -- it contains raw rock and is abundant in iron sulfides, which are similar to fool's gold," said Lisse, referring to a well-known Hawaiian volcano.

"It is fantastic to think we are able to detect the process of terrestrial planet formation. Stay tuned -- I expect lots more fireworks as the planet in HD113766 grows," he adds.

Lisse's paper has been accepted and will be published in an upcoming issue of Astrophysical Journal.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA.

The University of Maryland is responsible for overall Deep Impact mission science, and project management is handled by the Jet propulsion Laboratory.

Source: NASA/CalTech - Spitzer- Newsroom

NASA/JPL-Caltech/ C. Lisse (Johns Hopkins University Applied Physics Laboratory)


Birth of an Earth-like Planet

This artist's conception shows a binary-star, or two-star, system, called HD 113766, where astronomers suspect a rocky Earth-like planet is forming around one of the stars. At approximately 10 to 16 million years old, astronomers suspect this star is at just the right age for forming rocky planets. The system is located approximately 424 light-years away from Earth.

The two yellow spots in the image represent the system's two stars. The brown ring of material circling closest to the central star depicts a huge belt of dusty material, more than 100 times as much as in our asteroid belt, or enough to build a Mars-size planet or larger. The rocky material in the belt represents the early stages of planet formation, when dust grains clump together to form rocks, and rocks collide to form even more massive rocky bodies called planetesimals. The belt is located in the middle of the system's terrestrial habitable zone, or the region around a star where liquid water could exist on any rocky planets that might form. Earth is located in the middle of our Sun's terrestrial habitable zone.

Using NASA's Spitzer Space Telescope, astronomers learned that the belt material in HD 113866 is more processed than the snowball-like stuff that makes up infant solar systems and comets, which contain pristine ingredients from the early solar system. However, it is not as processed as the stuff found in mature planets and asteroids. This means that the dust belt is made out of just the right mix of materials to be forming an Earth-like planet. It is composed mainly of rocky silicates and metal sulfides (like fool's gold), similar to the material found in lava flows.

The white outer ring shows a concentration of icy dust also detected in the system. This material is at the equivalent position of the asteroid belt in our solar system, but only contains about one-sixth as much material as the inner ring. Astronomers say it is not clear from the Spitzer observations if anything is occurring in the icy belt, but they believe it could be a source of water later on for the planet that grows from the inner warm ring.

Source: NASA/CalTech - Spitzer- Newsroom

Laurel, Md. - U.S. astronomers said they believe an Earth-like planet is likely forming 424 light-years away in a star system called HD 113766.

Scientists at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., used the National Aeronautics and Space Administration's Spitzer Space Telescope to study a huge belt of warm dust swirling around a distant star that's slightly more massive than the sun.

The dust belt, which the APL astronomers said they suspect is clumping into planets, is located in the middle of the system's terrestrial habitable zone -- an area in which liquid water could exist. Earth is located in the middle of the sun's terrestrial habitable zone.

"The timing for this system to be building an Earth is very good," said Carey Lisse of APL. "Stay tuned -- I expect lots more fireworks as the planet in HD113766 grows."
go

Cool !

Shame I'll never get to go to any of these new planets that could be habitable ;(

Amazing. If it is possible to view a planet forming in the way that earth did(supposedly) then it is a possiblilty to make a conclusion to how earth was created. And when u have how it is created then u can make all kinds of theories and conclusins...

Aliens r possible lol

The University of Hawai‘i press release is reproduced below:

University of Hawaii
Contact: Eric Gaidos, (808) 956-7897
School of Ocean and Earth Sciences and Technology
Nader Haghighipour, (808) 956-6880
UH Institute for Astronomy
Posted: October 11, 2007

HONOLULU - In a paper published this week in the journal Science, three University of Hawaii at Manoa researchers and their colleagues review the prospects for discovering smaller planets more like Earth, some of which may even have conditions suitable for life. Astronomers reported the first planet around another Sun-like star in 1995 and since then have found more than 200 such planets, all thought to be “gas giants” made mostly of hydrogen and helium like Jupiter and Saturn in our Solar System.

“The most successful technique for discovering planets to date spreads light from the host star into its constitutive wavelengths (colors)” said lead author Eric Gaidos, who is an associate professor in the Department of Geology & Geophysics and the NASA Astrobiology Institute at UH Manoa. “A shift in wavelength, analogous to the change in pitch of the horn of a passing automobile, reveals any motion of the star along the line of sight. Monitoring of a star can detect periodic motion caused by the gravitational pull of any unseen, orbiting planet.”

Improved techniques and the ability to monitor fainter stars now enable astronomers to discover smaller planets, particularly planets orbiting much closer to their host star than the Earth is to the Sun. New computer simulations such as those performed by Sean Raymond, co-author of the paper and NASA Postdoctoral Fellow at the University of Colorado Boulder, show how such planets could form further out and then “migrate” inwards to such orbits.

Another method now used to find planets is to observe the slight decrease in light from the star as an orbiting planet passes in front of it. This happens only for those planets whose orbits by chance are seen edge-on. Jupiter-sized planets can be found this way using telescopes on the ground, but Earth-size planets might be detected by the European CoRoT spacecraft, now in orbit, and NASA’s Kepler spacecraft, scheduled to launch in 2009.

“These methods can sometimes be combined to estimate the density of the planet, which will tell us whether the planet is composed mostly of rock and metal, like Earth, or something else such as water ice,” said Gaidos.

Computational simulations by co-author Nader Haghighipour, a planetary dynamicist at the Institute for Astronomy and the Astrobiology Institute at UH Manoa, have shown that smaller Earth-sized planets can indeed exist in such tight planetary environments.

According to the paper, planets orbiting much closer to a star like the Sun will be much hotter and, like Mercury and Venus in our Solar System, inhospitable to life. However, many stars are much less bright than the Sun, and planets close to them could still orbit within a “habitable zone” where surface temperatures could permit stable liquid water.

“Explaining the formation of habitable planets in such environments is a challenging task. However, our simulations have been successful in determining condition under which planets similar to Earth can form in the habitable zones of less bright stars,” said Haghighipour.

Future space observatories beginning with NASA’s James Webb Space Telescope have the potential to study such planets and determine whether they have atmospheres or oceans.

Added Gaidos, “The discovery of another life-bearing planet would be a scientific triumph for humanity, but the study of many lifeless, un-Earthly worlds would nevertheless tell us about how planets form, and help us appreciate the Earth all that much more”.

Other researchers contributing to the paper were John Rayner of the Institute for Astronomy at UH Manoa, Eric Agol of the University of Washington and David Latham of the Harvard-Smithsonian Center for Astrophysics.

ABOUT THE SCHOOL OF OCEAN AND EARTH SCIENCE AND TECHNOLOGY
The School of Ocean and Earth Science and Technology (SOEST) was established by the Board of Regents of the University of Hawai‘i in 1988. SOEST brings together in a single focused ocean, earth sciences and technology group, some of the nation’s highest quality academic departments, research institutes, federal cooperative programs, and support facilities to meet challenges in the ocean and earth sciences, including the Hawai‘i Institute of Geophysics and Planetology (HIGP). Scientists at SOEST are supported by both state and federal funds as they endeavor to understand the subtle and complex interrelations of the seas, the atmosphere, and the earth. For more information, visit http://www.soest.hawaii.edu.

ABOUT THE INSTITUTE FOR ASTRONOMY
Founded in 1967, the Institute for Astronomy at the University of Hawai‘i at Manoa conducts research into galaxies, cosmology, stars, planets, and the sun. Its faculty and staff are also involved in astronomy education, deep space missions, and in the development and management of the observatories on Haleakala and Mauna Kea. For more information, visit http://www.ifa.hawaii.edu/.

Source: UH Press Release

The Gemini Observatory press release is reproduced below:

Monday, 08 October 2007

A Canada-US-UK team led by David Lafrenière and René Doyon of the University of Montreal has released the first results from the Gemini Deep Planet Survey (GDPS), a near-infrared adaptive optics search for giant planets and brown dwarfs around 85 nearby young stars. The observations, made with the ALTAIR/NIRI adaptive optics system at the Gemini North telescope, are aimed at constraining the population of Jupiter-mass planets with orbits that have a semi-major axis in the range of 10-300 astronomical units (AU). This work constitutes a first step toward the detection of the population of “outer” giant planets around other stars.


The use of angular differential imaging (see ADI "how-to" box below) in conjunction with NIRI/ALTAIR enabled the team to reach the best sensitivities to date for detecting giant exoplanets with projected separation above ~0.7 arcsecond. The typical detection limits (5 sigma) reached by the survey, in magnitude difference between an off-axis point source and the central star, are 9.5 at 0.5 arcsecond, 12.9 at 1 arcsecond, 15 at 2 arcseconds and 16.5 at 5 arcseconds, limits that are low enough to detect planets more massive than ~2 MJup with a projected separation of 40-200 AU around a typical target star. More than 300 faint candidate exoplanets were detected around 54 of the 85 stars observed, (see Figure 1) however, follow-up observations at a second epoch have revealed that all of the candidates were unrelated background objects. The observations also resolved three of the target stars into binaries for the first time.

A statistical analysis of the results indicates that the 95% credible upper limit to the fraction of stars harboring at least one planet more massive than 2 MJup with an orbit of semi-major axis in the range 25-420 AU or 50-295 AU is 0.23 or 0.12, respectively. These upper limits, the most precise to date, leave little room for the existence of a swarm of giant exoplanets orbiting their star at distances greater than the size of own planetary system.

More than 200 exoplanets have been discovered over the last decade through precise measurements of radial velocity (RV) variations of their primary star. Notwithstanding its great success in finding planets on small orbits around other stars, the RV technique cannot be used to search for and characterize planets with orbits larger than ~10 astronomical units (AU), i.e. larger than the orbit of Saturn in our solar system. A determination of the frequency of giant planets as a function of orbital separation to hundreds of AUs is necessary to elucidate the relative importance of various modes of planet formation and migration that are currently under scrutiny. This is why direct imaging searches for planets, such as GDPS, are crucial to improve our understanding of the formation and evolution of planetary systems.

For more details, see the article “The Gemini Deep Planet Survey – GDPS”, by David Lafrenière and 12 co-authors, scheduled for publication in the December 10, 2007, issue of The Astrophysical Journal.



Figure 2. A processed ADI sequence with the speckles
subtracted over the period of field rotation described in
the text in this box. Residual dark trails adjacent to
background stars are a result of processing artifacts
and illustrate the field rotation that occurred during the
period of this sequence. This image is from the GDPS
data using the ALTAIR/NIRI adaptive optics system.

Direct imaging is currently the only viable technique to probe for planets that have large orbits around other stars. However, directly detecting giant planets via imaging is very difficult due to the close angular proximity of the central star and the very large luminosity ratios involved: a young Jupiter-mass planet is expected to be approximately 10 million times fainter than its primary star when observed in the near-infrared. Currently, the main technical difficulty when trying to image giant planets directly comes from light scattering by optical imperfections of the telescope and camera that produce bright quasi-static speckles* in the image of the of the central star. These speckles are usually much brighter than the planets sought after (Figure 3). The GDPS team developed a special technique, called angular differential imaging (ADI), to suppress these speckles and achieve a greater sensitivity to exoplanets.

ADI consists of acquiring a sequence of many exposures of the target using an altitude-azimuth telescope with the instrument rotator turned off (at the Cassegrain focus) to keep the instrument and telescope optics aligned. This is a very stable configuration and ensures high correlation of the sequence of PSF images. This setup causes a rotation of the field of view during the duration of the sequence. For each target image in such a sequence, it is possible to build a reference image from other target images in which any companion would be sufficiently displaced due to the field of view rotation. After subtraction of the reference image, the residual images are rotated to align their field of view and co-added. Because of the rotation, the residual PSF speckle noise is averaged incoherently, ensuring an ever improving detection limit with increasing exposure time. It has been shown that for ADI with ALTAIR/NIRI on Gemini, the subtraction of an optimized reference PSF image from a target image can suppress the PSF speckle noise by a factor of ~12, and that a noise suppression factor of ~100 is achieved for the combination of 90 such difference images.

* Quasi-static speckles are essentially replicas of the ideal stellar image that appear in the vicinity of the star; they arise from small optical defects in the telescope and the instrument. Speckles look very much like thousands of point source companions. Subtracting the speckle pattern is essential for revealing the faint exoplanet signal which is in general much fainter than speckles.


Figure 3. Illustration of the speckle noise attenuation process achieved by ADI. Panel (a) shows a
typical image after subtraction of an azimuthally symmetric median intensity profile; panels (b) and
(c ) both show, with a different intensity scale, the same image after ADI subtraction; and panel (d)
shows the combination of 117 such speckle-subtracted images. The faint point source visible in panel
(d) at (2.43", 7.3º) is 1 million times fainter than the star.

Source: Gemini Observatory press release

The University of St Andrews press release is reproduced below:

31 October 2007

A St Andrews researcher is part of the leading team of planet-hunting astronomers that have announced the discovery of three new planets today (31 October 2007).



Professor Andrew Collier Cameron, of the University's School of Physics & Astronomy, played an important role in the recent discovery of three planets said to be as big as Jupiter, and named WASP-3, WASP-4 and WASP-5.

Professor Cameron is a member of the Wide Area Search for Planets (WASP) team, which also includes astronomers from the University of Keele and Queen's University Belfast. Using `super-cameras' in South Africa and the Canary Islands that monitor millions of stars over the entire sky, the latest finding makes them the only team to have found transiting planets in both the Northern and Southern hemispheres. The team are already responsible for the discovery of two new planets named WASP-1 and WASP-2 last year.

Professor Cameron, who measured the sizes of the new extra-solar planets, said, "All three planets are similar to Jupiter, but are orbiting their stars so closely that their 'year' lasts less than two days. These are among the shortest orbital periods yet discovered. Being so close to their stars the surface temperatures of the planets will be more than 2000 degrees Celsius, so it is unlikely that life as we know it could survive there. But the finding of Jupiter-mass planets around other stars supports the idea that there are also many Earth-sized planets waiting to be discovered as astronomers' technology improves."


Professor Andrew Collier Cameron

Over 200 extra-solar planets (those that orbit other stars, rather than our Sun) are currently known to astronomers. The three new planets were found as the WASP cameras detected small dips in the brightness of the host stars, caused when planets pass in front of, or transit, them. Studying such planets outside of our solar system allows scientists to investigate how planetary systems form.

Dr Coel Hellier of Keele University said, "When we see a transit we can deduce the size and mass of the planet and also what it is made of, so we can use these planets to study how solar systems form."

WASP-4 and WASP-5 are the first planets discovered by the WASP project's cameras in South Africa, and were confirmed by a collaboration with Swiss and French astronomers.

"These two are now the brightest transiting planets in the Southern hemisphere," said Dr Hellier. WASP-3 meanwhile is the third planet that the team has found in the North, using the SuperWASP camera sited in the Canary Islands.

Dr Don Pollacco, of Queen's University Belfast, said, "We are the only team to have found transiting planets in both the Northern and Southern hemispheres; for the first time we have both SuperWASP cameras running, giving complete coverage of the whole sky."

The WASP project is the most ambitious project in the world designed to discover large planets. Funding for the project comes from the three universities and the Science and Technology Facility Council.


Weblink: _www.superwasp.org/wasp_planets.htm


ENDS


NOTE:

The discovery of WASP-3, WASP-4 and WASP-5 is being announced by the WASP project this week at an international conference on extrasolar planets in Suzhou (near Shanghai), China.

Contacts

Professor Andrew Collier Cameron, University of St Andrews.
Tel: 01334 463147
Email: Andrew.Cameron@st-and.ac.uk

Dr Don Pollacco, QUB, WASP Project Scientist
Tel: 02890 973512
Email: d.pollacco@qub.ac.uk

Dr Coel Hellier, Keele University
Tel: 01782 584243
Email: ch@astro.keele.ac.uk

Gill Ormrod - Science and technology Facilities Council Press Office
Tel: 01793 442012. Mobile: 0781 8013509
Email: gill.ormrod@stfc.ac.uk


Issued by the Press Office, University of St Andrews
Contact Gayle Cook, Press Officer on 01334 467227 / 462529, mobile 07900 050 103, or email gec3@st-andrews.ac.uk
Ref: Trio of new planets 311007

Source: University of St Andrews Press Release

The media advisory is reproduced below:

Grey Hautaluoma
Headquarters, Washington
202-358-0668
grey.hautaluoma-1@nasa.gov

DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
david.c.agle@jpl.nasa.gov

Denize Springer
San Francisco State Univ.
415-405-3803
denize@sfsu.edu

Bob Sanders
University of California, Berkeley
510-643-6998
rsanders@berkely.edu

MEDIA ADVISORY: M07-151

Scientists Discover New Member of Exoplanet Family

WASHINGTON - Astronomers will announce new findings about a planetary system similar to our own at a media teleconference Tuesday, Nov. 6, at 1 p.m. EST. Funding for the study was provided by NASA and the National Science Foundation.

The briefing participants are:
- Debra Fischer - astronomer, San Francisco State University
- Geoff Marcy - astronomer, University of California, Berkeley
- Jonathan Lunine - planetary scientist, University of Arizona, Tucson
- Zlatan Tsvetanov - program scientist, NASA Headquarters, Washington

Reporters should call the Media Relations Office at NASA's Jet Propulsion Laboratory at 818-354-5011 for dial-in participation information. NASA will stream audio of the briefing live on the Web at:


At the start of the briefing, NASA will post supporting images and graphics at:


For information about NASA's planet-hunting missions, visit:


Source: NASA Media Advisory M07-151

PASADENA, Calif. - Astronomers have announced the discovery of a fifth planet circling 55 Cancri, a star beyond our solar system. The star now holds the record for number of confirmed extrasolar planets orbiting in a planetary system.

55 Cancri is located 41 light-years away in the constellation Cancer and has nearly the same mass and age as our sun. It is easily visible with binoculars. Researchers discovered the fifth planet using the Doppler technique, in which a planet's gravitational tug is detected by the wobble it produces in the parent star. NASA and the National Science Foundation funded the research.


Image above: This artist's concept shows
planets that orbit 55 Cancri, a star much like
our own.
Image credit: NASA/JPL-Caltech
+ Related animation

"It is amazing to see our ability to detect extrasolar planets growing," said Alan Stern, associate administrator for the Science Mission Directorate at NASA Headquarters, Washington. "We are finding solar systems with a richness of planets and a variety of planetary types comparable to our own."

The newly discovered planet weighs about 45 times the mass of Earth and may be similar to Saturn in its composition and appearance. The planet is the fourth from 55 Cancri and completes one orbit every 260 days. Its location places the planet in the "habitable zone," a band around the star where the temperature would permit liquid water to pool on solid surfaces. The distance from its star is approximately 116.7 million kilometers (72.5 million miles), slightly closer than Earth to our sun, but it orbits a star that is slightly fainter.


Image above: This artist's concept illustrates
two planetary systems - 55 Cancri (top) and
our own.
Image credit: NASA/JPL-Caltech

"The gas-giant planets in our solar system all have large moons," said Debra Fischer, an astronomer at San Francisco State University and lead author of a paper that will appear in a future issue of the Astrophysical Journal. "If there is a moon orbiting this new, massive planet, it might have pools of liquid water on a rocky surface."

Fischer and University of California, Berkeley, astronomer Geoff Marcy, plus a team of collaborators discovered this planet after careful observation of 2,000 nearby stars with the Shane telescope at Lick Observatory located on Mt. Hamilton, east of San Jose, Calif., and the W.M. Keck Observatory in Mauna Kea, Hawaii. More than 320 velocity measurements were required to disentangle signals from each of the planets.

"This is the first quintuple-planet system," said Fischer. "This system has a dominant gas giant planet in an orbit similar to our Jupiter. Like the planets orbiting our sun, most of these planets reside in nearly circular orbits."

"Discovering these five planets took us 18 years of continuous observations at Lick Observatory, starting before any extrasolar planets were known anywhere in the universe," said Marcy, who contributed to the paper. "But finding five extrasolar planets orbiting a star is only one small step. Earth-like planets are the next destination."

The planets around 55 Cancri are somewhat different from those orbiting our sun. The innermost planet is believed to be about the size of Neptune and whips around the star in less than three days at a distance from the star of approximately 5.6 million kilometers (3.5 million miles). The second planet is a little smaller than Jupiter and completes one orbit every 14.7 days at a distance from the star of approximately 18 million kilometers (11.2 million miles). The third planet, similar in mass to Saturn, completes one orbit every 44 days at a distance from the star of approximately 35.9 million kilometers (22.3 million miles). The newly discovered planet is the fourth planet. The fifth and most distant known planet is four times the mass of Jupiter and completes one orbit every 14 years at a distance from the star of approximately 867.6 million kilometers (539.1 million miles). It is still the only known Jupiter-like gas giant to reside as far away from its star as our own Jupiter is from our sun.

"This work marks an exciting next step in the search for worlds like our own," said Michael Briley, an astronomer at the National Science Foundation. "To go from the first detections of planets around sun-like stars to finding a full-fledged solar system with a planet in a habitable zone in just 12 years is an amazing accomplishment and a testament to the years of hard work put in by these investigators."

For visuals depicting the new planets on the Web, visit:

_http://www.nasa.gov/audience/formedia/telecon-20071106/

or

_http://planetquest.jpl.nasa.gov/news/ssu_images.html

For information about NASA and agency programs, visit:

_http://www.nasa.gov


Media contacts: DC Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
agle@jpl.nasa.gov

Grey Hautaluoma 202-358-0668
NASA Headquarters, Washington
grey.hautaluoma-1@nasa.gov

Denize Springer 415-405-3803
San Francisco State University, Calif.
denize@sfsu.edu

Bob Sanders 510-643-6998
University of California, Berkeley
rsanders@berkeley.edu

2007-128

Source: NASA - Exp