## Albireo

Frank
Ensign
Posts: 11
Joined: Sun Jul 17, 2005 3:17 am

### Albireo

I found the article about Albireo very interesting and have a few questions to ask.

The distance to Albireo is reported to be 380 light years from our Sun, but the distance between the two stars was not mentioned although they take 75,000 years to orbit each other. Is it possible to determine their average distance from each other?

Another question I have is how far can two stars be apart and yet orbit each other? Have orbiting or twin stars evolved from their births or are they captured at a later time?

What percentage of stars orbit one or more other stars?

Are there any "twins" or "trios" that are existing without being part of a galaxy?
Thank you for answering any of my questions. Frank

makc
Commodore
Posts: 2019
Joined: Tue Oct 12, 2004 5:25 pm

### Re: Albireo

Frank wrote:What percentage of stars orbit one or more other stars?
100%. No, really - gravity is everywhere (but if you wouldn't use "or more" part, answer would be different;) )

Odegard
Ensign
Posts: 16
Joined: Tue Jun 14, 2005 11:10 pm
Take a quick peek at Kepler's laws.

http://hyperphysics.phy-astr.gsu.edu/hbase/kepler.html

"The square of the period of any planet is proportional to the cube of the semimajor axis of its orbit."

P^2 = a^3

P is measured in years, and a is the semimajor axis measured in AU (mean distance Earth-Sun, ~150million kilometers)

So, 380^2 = 144400, and 144400^(1/3) = 52,5

Of one of the stars were the sun, the other would be 25% farther out that Pluto (Sun-Pluto = 40AU)