Determining Distance Between Stars

[Sunchaser]

I recently read that Nunki has a companion 5.2' away. No other information was given, other than magnitude. I tried to figure out what the true distance would be, and came up with the rather surprising distance of almost 22,000 AU (.34 ly).

Not being a math whiz, I'm assuming that I calculated something wrong. Here's the formula I used...

a= D X Theta (substitute for the Gr. character.)

a: the orbital distance
D: the stellar distance in parsecs
Theta: the angular distance in arcseconds.

in short...it came up like this

a=69.8 X 312

a=21777.6

I found a program online and it seemed to give me the same answer. I still am not sure. Anyone care to confirm this/ prove me wrong? (Like I said, I'm no math whiz, so I don't mind.)

Thanks

-M-

[Hungry4info]

I set it up as a trig problem,

tan ? = a/D

and arive at the same answer you got.

But this is a projected (and thus, minimum) distance. The star could be closer or farther away from Earth, while having the same separation in the sky from ? Sgr.

[Sunchaser]

I would accept that as a very real possibilty. I guess I wasn't terribly surprised...Delta Cephei has a companion .2 ly away, so I figured it wouldn't be all that odd. Thanks for the confirmation, though.

-M-