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General Discussion => Q&A Section => Topic started by: cube on 02/22/2022 03:15 pm

Title: Orbit of the star Sirius B
Post by: cube on 02/22/2022 03:15 pm

Hello, star Sirius A is about 8.6 ly from Earth Sirius B orbiting Sirius A is about 8.7 ly from us (a difference of 0.1 ly or 6324 AU), yet Sirius B's orbit is at maximum at 31.5 AU from Sirius A and even taking into account the margin of error of their parallax the two stars are still much further apart than 31.5 AU. What can explain this?

Title: Re: Orbit of the star Sirius B
Post by: Orbiter on 02/22/2022 03:33 pm

Sirius is exactly 8.611 lyr from Earth. Sirius B being listed as being 8.7 lyr from Earth is probably just a typo or an error.

Title: Re: Orbit of the star Sirius B
Post by: daedalus1 on 02/22/2022 03:33 pm

Your distance from earth is wrong. They are the same distance.

Title: Re: Orbit of the star Sirius B
Post by: cube on 02/22/2022 04:23 pm

I found the parallax of the two stars here:
Sirius A: http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=sirius+a&submit=SIMBAD+search
Sirius B: http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=sirius+b&submit=SIMBAD+search

and here for a parallax calculator to be faster: https://www.translatorscafe.com/unit-converter/fr-FR/calculator/parallax-distance/

And I looked at the Sirius B star on the Gaia catalog and it has the same parallax as on simbad.
This error is weird