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Tucson_Tim
2007-Aug-09, 03:04 PM
I know one of our resident astrophotographers has a pic of the double-star Albireo on file.

Please post one for us who live vicariously thru your photos. :)

Galactic2000
2007-Aug-09, 07:40 PM
I know one of our resident astrophotographers has a pic of the double-star Albireo on file.

Please post one for us who live vicariously thru your photos. :)

Here is the Albireo Image you requested.

It was taken with my backyard obsevatory, a 10" lx200 SCT with a QHY2 CCD 3.3 megapixel camera for a 5 minute exposure.

What do you need the image for?
Just Curious!

Tucson_Tim
2007-Aug-09, 07:43 PM
Here is the Albireo Image you requested.

It was taken with my backyard obsevatory, a 10" lx200 SCT with a QHY2 CCD 3.3 megapixel camera for a 5 minute exposure.

What do you need the image for?
Just Curious!

No reason. Just wanted to see one - one of my favorites. Thanks!

Tucson_Tim
2007-Aug-10, 04:00 AM
I have a question about Albireo. This is from Wikipedia:



They had been considered as merely an optical double, not orbiting around a common point as a true binary star system would be. However, in spite of the large distance between them, it has been shown that they are a true binary system.

The brighter, yellow member of the pair, Beta Cygni A, is itself a close binary.


The blue star is smaller than the yellow star. I thought blue stars were always large massive stars and yellow stars were much smaller, like Sol. Am I wrong about blue stars?

Bokmakierie
2007-Aug-10, 05:49 AM
This one is my very favorite. Alpha Centauri - our closest star. Imaged afocally from my backyard through a 9" homemade Dob. Fujifilm Finepix 2600 digicam.

Phil

RickJ
2007-Aug-10, 07:19 AM
I have a question about Albireo.
The blue star is smaller than the yellow star. I thought blue stars were always large massive stars and yellow stars were much smaller, like Sol. Am I wrong about blue stars?

That's true IF both stars were main sequence stars calmly fusing hydrogen into helium. The blue star is doing exactly that. But not the more massive and brighter yellow orange star. It's not smaller either in size or mass. It is fusing helium. This makes the core of the star much hotter than the one in the blue companion. So why isn't it even bluer? It was! When it too was fusing hydrogen it was bigger and hotter thus bluer than its blue companion. But it ran out of hydrogen to fuse so had to switch to helium. This makes the core even hotter than before. When the core heats up the outer envelope of the star must expand due to the increased radiation pressure. When gas expands it cools. It expands so much the hot core can't heat it very much before it radiates away the energy so it stays cool and yellow orange. But the huge surface area makes it very bright in keeping with its much hotter, more massive, core. Helium fusion, while hotter, requires tremendous quantities of helium so it won't be long before it runs out of helium. By then though the companion may have also turned into a giant helium burning star. So it will then be a giant orange star but by then the now yellow orange star will have run out of helium and be fusing even heavier elements which will make it even redder as it expands further. Or it may have run out of fuel entirely. Most likely, before that happened it will have blown away most of its outer envelope in a tremendous solar wind and lost so much mass it likely won't go super nova but if that doesn't happen then blam.

Stick around for a few million years and see what happens.

For your info as best as I can find out the yellow orange star is 5 solar mass and about 50 times the sun's diameter making it 900 to 1000 times brighter than the sun. The blue star is about 3.3 solar mass and about 190 times the sun's luminosity. Size is a bit difficult as it rotates in 0.6 days and surrounded by a highly luminous shell of gas and is likely somewhat flattened by the rotation. It would be about 2 to 3 solar diameter from what little I can find on it.

Tucson_Tim
2007-Aug-10, 02:16 PM
RickJ, Thanks for the explanation!

Kyle Edwards
2007-Aug-15, 12:58 PM
I remembered this thread the other night while I was imaging, and took this shot of Albireo.

http://gallery.caasastro.org/v/member/kedwards/doublestar/Albireo+8_10_2007.jpg.html

Tucson_Tim
2007-Aug-15, 02:18 PM
I remembered this thread the other night while I was imaging, and took this shot of Albireo.

http://gallery.caasastro.org/v/member/kedwards/doublestar/Albireo+8_10_2007.jpg.html

Very nice. Great colors!