--- On Mon, 5/18/09, Spencer Ball <spencer@spencerball.com> wrote:
From: Spencer Ball <spencer@spencerball.com> Subject: Re: [Utah-astronomy] Albireo: a double star? To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Monday, May 18, 2009, 10:00 AM Albireo separated by only 34AU? At 380 light years away, that would make them at most `/4 second apart! And they would revolve around each other in tens of years at most. They would have to be about 100 times farther apart to have a 75,000 year period.
They must be farther apart.
Spencer Ball
Looking at the Wiki data, I see that the pair does not share the same proper motion across the sky. The distance uncertainty is 30 light years. Taking the separation in arcseconds, converting to degrees, taking the SINE, multiplying by the distance, and coverting from lightyears to AU, I get a distance of close to 4000AU. Now that would be the minium distance if they were both in the plane of the sky as viewed from earth, one could easily be a lightyear or more farther from earth than the other. DT