[vsnet-chat 4229] Re: Omega CMa comparison stars

[Taichi Kato <tkato>]

Re: [vsnet-chat 4228] Re: Omega CMa comparison stars

>    A supergiant A-star (3 Pup) is likely to be a microvariable, 
> especially if it shows emission lines in its spectrum.  It could be
> used as long as stars for which no variability has ever been found,
> such as HR 2922, are included as checks.  Unfortunately, 3 Pup is the
> only potential comparison star that is brighter than Omega CMa and
> is also similar in color.  One of those unfortunate, but necessary,
> compromises when doing photometry of bright stars. 

   3 Pup = NSV17577 is a suspected variable with a range of 3.68-3.92R.
Hipparcos recorded microvariability with a range of 4.00-4.03 Hp.
This star in itself is a high luminosity early type emission line object
(MWC 570), close to B[e] stars in nature, and is a good target for continuous
photometric monitoring.  Indeed E. Eker has been already regularly reporting
this "variable" star.  This star should not be used as a comparison star.

Regards,
Taichi Kato

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