[vsnet-alert 11261] Re: re New flare star candidates

kstars at Safe-mail.net kstars at Safe-mail.net
Fri May 22 20:11:24 JST 2009


Brian Skiff advised :-

"The strong CaH that MacConnell mentions merely shows that it is a dwarf, not necessarily a subdwarf.
Higher resolution data are required for that.  Subdwarfs are still on the main sequence, but simply at lower metallicity, so the B-V color is bluer, so seem to be shifted straight left on the ordinary V versus B-V color-magnitude diagram."

Thanks for the CaH significance update, I didn't know that it was a general M dwarf thing.  The whole "late" end of the Main Sequence seems to be undergoing something of a review and classification reform since the advent of the L and later dwarfs.

It seems to turn out that pre M B-V is bluer, but at M and later likely redder than norm (where "norm" is the extrapolated trend of the general Main Sequence).

Also, it reminds me with respect to the spectroscopic surveys that a considerable increase in availability of said of late, in terms of adding updated coordinates to identities (some of which latter are little more than a number written directly onto an exposure plate), is purely due to the not inconsiderable efforts of Brian Skiff.

It's surprising how much spectral info there is out there in literature land, and thanks to Brian S.'s efforts, it's increasingly becoming available in an accessible form.

Cheers

John


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