What's going on with those "flashing stars"?

[JayMark]

In the night sky I can easily spot two evident ones. If I recall, one is about 15° west of Venus and the other one about 45° east of it in the sky of southern Québec (less than 100 km from Vermont). I'll check with my compass next time.

They are those who flash in diffrent colors. One (west of Venus) flashes between red, orange and yellow. The other more "intense" (east of Venus) flashes between blue and dark red.

Are they dying stars? I guess the diffrent colors are showing fluctuations in irradiance, red being less energetic, blue being more. I don't know. Maby our atmosphere/magnetic field could have something to do with it as well.

Thanks for the input.

Peace.

[TSS]

They all do it, the lower down the horizon the more prominent they are, due to the nature of viewing light through the curved lens that is our atmosphere...

If you want to see one that's about to go bang (relatively speaking - or might have already, we don't know yet) look for betelgeuse, it's sitting in the top left hand corner of Orion, slightly redder then all the stars around it..

[Mentalcase]

And right below Orion, is the star Sirius (the most common of the blinking stars). The process is called scintillation.

[GoldenWolf]

In the night sky I can easily spot two evident ones. If I recall, one is about 15° west of Venus and the other one about 45° east of it in the sky of southern Québec (less than 100 km from Vermont). I'll check with my compass next time.

They are those who flash in diffrent colors. One (west of Venus) flashes between red, orange and yellow. The other more "intense" (east of Venus) flashes between blue and dark red.

Are they dying stars? I guess the diffrent colors are showing fluctuations in irradiance, red being less energetic, blue being more. I don't know. Maby our atmosphere/magnetic field could have something to do with it as well.

Thanks for the input.

Peace.

I think the one to the west you are referring to is ALGOL, A.K.A. The demon star. The other is more than likely SIRIUS

Edited April 18, 2012 by HavocWing

[ZaraKitty]

I always thought they were satellites.

[ChrLzs]

Satellites are the ones that look like high-flying aircraft, but *don't* have the blinking nav lights.. They have several characteristics:

1. For mid latitudes, they are only seen for an hour or two after sunset or before dawn, as they require the Sun's rays passing overhead to illuminate them.. If it's near midnight and you see a light moving overhead, it won't be a satellite.

2. They will often vanish as they move into the earth's shadow (whereas aircraft will simply fade into the distance).

3. They will sometimes change their appearance and brighten or darken as the sun hits their solar panels or other flat or shiny surfaces. A few satellites are known for their bright flashes from solar panels - look up 'Iridium flare'.

Because stars are so distant, the light from them that hits your eye is an incredibly thin, almost single file line of photons. Any atmospheric disturbance between your eye and the star results in the 'scintillation' effect - the lower to the horizon and/or the more unstable the air, the more the 'flashing' and colour changes.

Sirius is notorious for this - when it is low to the horizon, it produces beautiful flashing effects with rainbow like changes in colour.

Planets, like Venus, have a detectable disk of photons so there are more to be 'averaged' when they hit your retina and they are less affected by the atmosphere. They do still scintillate a little, but nowhere near as much as stars - hence it's a useful way to tell them apart.

[csspwns]

blue stars are the hottest stars and biggest. yellow stars are the second hottest and are second biggest, not quite sure bout the orange stars( prob dying stars ) and the red stars are the ones w/ the least heat and have the shortest lives

[Waspie_Dwarf]

blue stars are the hottest stars and biggest. yellow stars are the second hottest and are second biggest, not quite sure bout the orange stars( prob dying stars ) and the red stars are the ones w/ the least heat and have the shortest lives

It doesn't work quite like that.

Colours indicate surface temperature, but not necessarily size or life span. For example spectral type O is a blue star. There are spectral type O hypergiants which are massive, short lived stars. There are spectral type O main sequence dwarfs, these are small, long lived stars and there are spectral type O white dwarfs, these are degenerate stars produced after a star leaves the main sequence and has gone through the red giant stage but are not massive enough to become neutron stars.

I suggest you put the terms "main sequence" and " Hertzsprung–Russell diagram" into a search engine. These would be good starting places to learn about star types, it's better than guessing.

[ShadowSot]

I'm not sure that any stars are actually close enough to be distinguished by color when viewed by eyeball in atmosphere, are you aware of any Waspie Dwarf?

[Waspie_Dwarf]

I'm not sure that any stars are actually close enough to be distinguished by color when viewed by eyeball in atmosphere, are you aware of any Waspie Dwarf?

Distance isn't really the issue, apparent brightness is.

Only brighter stars show colour to the unaided eye. Several of the red giants are quite obviously red to the naked eye, Aldeberan, Betelgeuse and Antares come to mind. In fact Antares gets its name because of its red colour, it means rival of Mars (the Greek equivalent of Mars being Ares). Vega has a bluish colour. I'm sure there are more.

With binoculars a lot more stars show colour

[ChrLzs]

I'm not sure that any stars are actually close enough to be distinguished by color when viewed by eyeball in atmosphere, are you aware of any Waspie Dwarf?

?? Crikey. Are the skies in Florida that badly polluted? I live in the outer suburbs of a large city, and I can still see many of the coloured stars, and many, many more with the addition of a simple pair of binoculars.

For anyone who doesn't get out and look up at your night sky, I'd have to ask - why not? It is a beautiful, and majestic (yet humbling, in a nice way) sight to be able to look out across the universe. And from a good, dark location, the Milky Way is just breathtaking, as is the sheer number of stars. If you haven't seen a clear night sky from an un-light-polluted location, you have not lived.

As Waspie stated, there are many notable coloured stars, here's a longer list in no particular order (just testing my memory..!):

Betelgeuse in Orion (red)

Antares, in Scorpio (red)

Vega in Lyra (blue)

Altair in Aquila (yellow-white)

Rigel in Orion (blue)

Capella in Auriga (yellow-white)

Albireo in Cygnus (blue-green and yellow double star - need good binoculars or telescope)

Arcturus in Bootes (Orange)

Pleiades in Taurus (open cluster of stars in bluish nebulosity)

Aldebaran in Taurus (red)

Jewel Box in Crux (open cluster with multiple colored stars, southern hemisphere only)

Sirius in Canis Major (very bright white, scintillates red and blue)

Canopus in Carina (yellow-white)

Procyon in Canis Minor (yellowish)

Algedi in Capricorn (yellow and orange double stars, need binoculars or good eyesight and clear sky)

I'm sure I've missed some, and maybe got some wrong, but that'll do.. If you don't know how to find these, get yourself a star chart, or better yet, a free copy of Stellarium. Stellarium is a great way to learn your sky, identify planets, find constellations, etc. And it *looks* awesomely real, and ya can't complain about the price!

[Waspie_Dwarf]

I can't believe I forgot Rigel. Being so close to Betelgeuse it provides a nice comparison of colours.

[ShadowSot]

?? Crikey. Are the skies in Florida that badly polluted? I live in the outer suburbs of a large city, and I can still see many of the coloured stars, and many, many more with the addition of a simple pair of binoculars.

Must be, I can only make out a few stars most of the time. Even with a pair of binoculars, mostly I can see planets and a few stars.

Now when I get to places like a national park I can see much more, but haven't been to one for a few years now.

thanks for settingme straight, next time I have the chance I'm bringing my binocs with me.

[Miss Shadows]

What I find interesting is that the light a star gives off at any given moment won't reach us on earth for quite some amount of time.

[Waspie_Dwarf]

What I find interesting is that the light a star gives off at any given moment won't reach us on earth for quite some amount of time.

That is true of absolutely everything you see. Because light has a finite speed then any light reaching you will have taken a finite time to arrive, it is just that because the speed of light is so fast (300,000km/s, 186,000mps) that for normal experience it is as good as instantaneous. It becomes noticeable in astronomy because of the huge distances involved.

[rashore]

Do you actually use Stellarium Chrizs? Do you really like it?

I'm fortunate in that I live in the boonies now. I can see stars twinkle, and different colors, and the Milky Way with the naked eye. Hehe, it was easy enough to point out the big dipper while in the city- it was one of the few things that showed up at all. But out here, there's just too many stars in the sky, and I'm finding it more difficult to pick out constellations. I just re-learned the basics on how to read a star map recently, and now I'm starting to shop around for some resources to help me figure out the heavens. Stellarium sounds great because it's free. Anyone else have suggestions on good resources to help me learn the heavens?

[ChrLzs]

Do you actually use Stellarium Chrizs? Do you really like it?

Absolutely. Not only for my own sky, but also to help others - if someone in the US or elsewhere sees a particular star at a particular time, I can change the location in Stellarium, and then check out what their sky would have looked like. I can also go back and forward in time, look at conjunctions and even watch eclipses as they happened (or will happen)..

About the only thing that bugs me about it is the time system - it's not all that easy to change time zones as you change locations.

But for normal use, like yours, I would recommend it without hesitation.

Also get yourself a good book (I quite like the 'Collins Guide to the Stars and Planets' - smallish but comprehensive), and spend more time outside looking up. Gradually you will become more and more familiar with your sky.

Lastly, get some good binoculars - if you have young eyes, 7x50's are good, if you are older maybe 10x50.

Edited June 4, 2012 by Chrlzs