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Calculating Barycentre RA/Dec of hyper-wide Binaries?

Posted: 20.04.2013, 05:48
by PlutonianEmpire
I've noticed that a number of stars in Celestia containing two or more stellar components that have barycenters defined, but without orbital data; being instead placed by the traditional RA and Dec coordinates and distance.

So, how does one calculate the barycenter in situations like that; and also if one wanted to implement orbital definitions (real or fictional) of their own for said binaries, like what was apparently done for ALF Cen?

Re: Calculating Barycentre RA/Dec of hyper-wide Binaries?

Posted: 08.06.2013, 03:21
by PlutonianEmpire
God damn it guys! I'm tired of my questions repeatedly going unanswered. :evil:

Out of 38 threads that I have started in this subforum alone, at least 8( :!: ) of my questions remain unanswered -- a full 21% of them! Yes, it's spread out over a multi-year period, but it doesn't make it any less infuriating and ridiculous. :evil:

Anyways, here's a 9th ( :!: ) one that will need to be answered. It's sorta related to the above, so no new thread.

I've notice that astronomers say something is x milliarcseconds (mas) wide or y mas apart, and from there say it is x kilometers wide or y AU apart. So, how do I convert mas into km or au or other units? (And/or sky coordinates into lengths or distances in general, or something?)

Re: Calculating Barycentre RA/Dec of hyper-wide Binaries?

Posted: 08.06.2013, 07:07
by John Van Vliet
--- edit ---

Re: Calculating Barycentre RA/Dec of hyper-wide Binaries?

Posted: 08.06.2013, 23:07
by Chuft-Captain
Firstly,
Try being a bit more polite. Having a tantrum because people haven't answered your questions will not help your cause. No-one here is obligated to answer your questions, so being rude, demanding or petulant, will not encourage people to help you.

Secondly,
If you've had 71% of your questions answered then I would say you are well above the average. I wish I had that success rate with questions I've asked over the years!

Thirdly,
You could also learn to show a little more initiative. These days you have the luxury of all information being easily available to you in the form of the internet, so take advantage of this fact. This will also benefit you by developing your own research skills and abilities, so that you no longer have to rely on other people to simply solve your problems for you.
eg. A GOOGLE search for "orbital period physics" would have given you all the answers you need to solve your first question.

Simple trigonometry (hint: of triangles), assuming you know the distance to the stars, and a known or assumed orientation, will solve your second question.

Re: Calculating Barycentre RA/Dec of hyper-wide Binaries?

Posted: 08.06.2013, 23:42
by PlutonianEmpire
Well, search engines almost never give me what I'm looking for, so when someone says they get all they need from search engines, I find it genuinely difficult to believe them. I try every combination of terms and expressions that I can think of, and my success rate is still only 10% at best. So either search engines are bs, or I just plain suck at using them, so forgive me if, god forbid, I resort to depending on asking questions. :|

Regardless, I apologize.

EDIT: Yes, I'm exaggerating; it's more than 10%, but still... And a lot of times, I post a question because I failed to find what I'm looking for after searching (through both search engines and navigating link after link after link). Although about half the time, I continue searching past that and reach my goal, and the answers sometimes actually end up helping me even more in addition to what I found while I waited.