[vsnet-chat 321] Re: Possible new UG in Pisces

[Toshihito Ishida <ishida@nhao.go.jp>]

Dear Kato-san and vsnet-chatters, 

Sorry for replying to an old post.  

In the vsnet-chat 218 on 15 April 1997, Kato-san wrote that
>
> One question.  I believe these "IS" stars with occasional fadings 
> are currently interpreted as young stars surrounded by circumstellar 
> disks part of which causes eclipse-like fadings.  Does this scenario 
> apply to RZ Psc, or is there other explanation of such fadings?  
> Since RZ Psc is not apparently associated with a dark cloud (natural 
> at this high galactic latitude), it does not seem to me so young.

As you might know, there are some investigations on stars escaped 
from Galactic disk, so called runaway stars.   It seems important 
and interesting to confirm whether RZ Psc has some features for 
young stars or not from other information than its position.  

If RZ Psc appears to be young object, and if the average absolute 
magnitude of this class of stars is known, we can estimate its 
distance from galactic plane.  If we further have velocity dispersion 
in Galaxy for this kind of stars, we can estimate its 'journey time' 
to get to the present position from Galactic plane.  If the estimated 
journey time is extremely larger than the life time of this class of 
star, runaway scenario is impossible, and we need other scenario,  
such as it's a 'pseudo young object' and not really young, or it's 
really young and there is some star formation activity in halo.  

regards, 

-- 
%  Toshihito ISHIDA, Ph. D., Astrophysicist
%  Nishi-Harima Astronomical Observatory, Sayo-cho, Hyogo 679-53, JAPAN
%  Tel: +81-790-82-3886 ext. 142 Telefax: +81-790-82-3514
%  e-mail: ishida@nhao.go.jp(office) HQA01560@niftyserve.or.jp(private)

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