Celestia Forums

One possibly interesting extension project at the binary star front that would be in perfect agreement with my general criteria, is to cross merge/compare/complement the visualbins.stc and spectbins.stc data with the relatively new orbital data about multiple stars in the HIP and TYCHO catalogs:

There are 3 relevant subfiles of the

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I/239 ESA Hipparcos and Tycho Catalogues
http://cdsarc.u-strasbg.fr/viz-bin/ftp-index?I/239
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hip_dm_o.dat 337 235 Double and Multiples: Orbital solutions
hip_dm_v.dat 144 288 Double and Multiples: VIM solutions
hip_dm_x.dat 22 1561 Double and Multiples: Stochastic solutions

The file called hip_dm_o.dat contains /in principle/ a complete set of orbital elements for 235 objects and a quality flag for each multiple system orbit. So we are talking about a similar order of magnitude as in my present data files. Yet we could use this additional set to sharpen our weapons, as to a better definition and comparison of multiple star data sets!

I have these data listings since quite a while, but was put off by the apparent danger of collisions with Grant's nearstar.stc data set. But perhaps NOW, we can find a good new strategy, given Grant's recent replies...

F.

Sounds like an interesting project, but the lack of information about mass ratios is unfortunate for the current Celestia convention of defining orbits relative to the system barycentre.

ajtribick wrote:Sounds like an interesting project, but the lack of information about mass ratios is unfortunate for the current Celestia convention of defining orbits relative to the system barycentre.

Yes, sure, as I emphasized already: there's no "free lunch".
And one cannot simply add mass ratios from other sources without refitting the orbit solutions...
(see viewtopic.php?f=4&t=12247&start=16)

F.

Another potentially interesting catalogue to implement (looking ahead to further in the future) would be this one, but Celestia would need support for general Roche lobe objects, and a cross-index between Hipparcos and variable star designations would be needed.