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Thread: Do Sirius A and B have opposite spin ?

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    Default Re: Do Sirius A and B have opposite spin ?



    Thank you again not_Fritz_Argelander,

    it's very appreciated.

    regards,

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    Default Re: Do Sirius A and B have opposite spin ?

    Quote Originally Posted by not_Fritz_Argelander View Post
    The only hope of doing that is for stars close enough to have their disks resolved by interferometry for instance. Achernar is one example. There aren't many others! If any! (See link at end.)
    But wait a second... how come astronomers can resolve by interferometry Achernar (situated at 140 ly) and not Sirius (situated at ~ 8 ly) ?

    Did I miss something ?

    regards,

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    Default Re: Do Sirius A and B have opposite spin ?

    Hi !
    About spin broadening of lines in the spectrum due to Doppler effect, it can't indicate the spinning direction, because half of the star is approaching (the left or the right one) and the other is moving away so in both cases of spinning, the spectral line is broadening the same way.
    That was, during a long time, the same case for the galaxies : were they winding or unwinding their arms ?
    Arsène
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