[vsnet-chat 5504] Re: UV stars (FZ And, HW And)

[Seiichi Yoshida <comet@aerith.net>]

Dear Sebastian,

> In spite of its suggerent name, UV-type stars are not hot stars but red
> dwarves as you guessed.
> They show flare activity and may increase its brightness by several times
> in a matter of seconds.
> The name "UV" comes from its prototype star, UV Ceti.

Thank you for your information. Now I see.

But I have two questions still now.

(1)	In the case of FZ And, it is 13.8 mag(R) in USNO-A2.0. But it
	was fainter than 15.4 mag always on the MISAO unfiltered
	red-sensitive CCD images on 7 nights.

	Does it mean that FZ And was in flare on the USNO-A2.0 plate
	by chance?

(2)	In the case of HW And, the range is 12.7-14.4 mag
	(photographic). However, it was as bright as around 12.3 mag
	always on the MISAO unfiltered red-sensitive CCD images.

	Does it mean that the normal magnitude of HW And is around
	12.3 mag(unfiltered CCD) and 14.4 mag(photographic)? But if
	so, FZ And must be detected from MISAO images, because the
	normal magnitude of FZ And at 16.25 mag(B) probably comes to
	14.3 mag(unfiltered CCD) or so.

	Or, does it mean that HW And was in flare so frequently?

Best regards,

--
Seiichi Yoshida
comet@aerith.net
http://vsnet.aerith.net/

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