[vsnet-chat 3248] Re: TV Hya

[Taichi Kato <tkato>]

Re: TV Hya

> A9V TV Hya appears to possibly be a bit of a fast rotator [vsini maybes
> 70km/s or faster], and there seems to be no evidence of spectroscopic
> binarity.
> 
> An A7 IV/V star that is a far faster rotater, and possibly
> microvariable, is called Altair.

   ROSAT data on Altair:

195046.9 +085158 (2000.0) 1RXS_J195047.0+085159 0.148 -1.00 0.00

   The spectrum is very soft.

   TV Hya:

133710.8 -233701 (2000.0) 1RXS_J133710.9-233702 0.061 -0.31 -0.14

   Although TV Hya is by more than 6 maignitudes fainter than Altair,
the ROSAT flux is only less than 1 magnitude fainter.  This already indicates
the high Lx/Lopt in TV Hya.

   Another interesting point of TV Hya is its apparent discrepancy in
spectral classifications.  SAO = GCVS: A3, Michigan = Buscombe: A9V.
This discrepancy may have resulted from the rapid rotation?

   Anyway, I have long been wondering what variability was responsible
for the GCVS E: classfication.  As many variable star observers know,
TV Hya is quite close to R Hya, and has received much attention.

Regards,
Taichi Kato

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