July 11
Since 1995, astronomers have found more than 230 "super Jupiters" orbiting very close to their parent stars using the radial velocity method. This indirect planet-detecting technique measures the slight back-and-forth motion of the star as it is tugged by an unseen planet's gravity.
However, the radial velocity method presently used is most sensitive to planets close to their stars. The technique reveals little about extrasolar planets farther out in nearby solar systems.
Astronomers need other techniques to map extrasolar planets beyond 5 AU so they can determine what the "average" planetary system looks like -- and whether ours is a typical solar system.
One AU is the distance between Earth and the sun.
There is no 'planet oasis' between 20 and 100 AU. There were contrasts high enough to find these super Jupiters, but didn't." 20 AU is the orbital distance of the planet Uranus in our own solar system.
Astronomers were surprised in the early days of planet finding to discover a population of planets more massive than Jupiter, within the orbit of Mercury, taking only a few days to orbit their host star.
The team used Close's novel Simultaneous Differential Imager (SDI) for observations.
The SDI devices made the highest contrast astronomical images ever made from ground or space of methane-rich companions within an arc second of their stars. (An arc second is the diameter of a dime seen from two miles away).
go
