[vsnet-chat 2567] Re: NSV4189 Hydrae - A Large Amplitude Red Variable

["William S G Walker" <astroman@voyager.co.nz>]

Peter,

Sounds an interesting star. I'll try to keep a watch on this and perhaps
it's within range of Arne for a better sequence. If not, I'll pop off a few
frames if the weather ever clears. I'll also make some V filter measures as
long
as it's viewable. 

I've been doing an analysis of the RASNZ VSS Mira stars for a while. I
noted that those with periods in excess of 400 days include the ones with
unstable periods, or even the double maxima ones such as  R Cen and R Nor.
BH Cru does everything - the period changed from 421 to 508 days in several
steps from 1970 to 1992 as well as changing from double peaked to single
peak and perhaps back again. 

Maybe you've added another to this interesting group?

Regards,
Stan

----------
> From: PETER F WILLIAMS <PFWILLIAMS@onaustralia.com.au>
> To: vsnet-chat <vsnet-chat@kusastro.kyoto-u.ac.jp>
> Subject: [vsnet-chat 2560] NSV4189 Hydrae - A Large Amplitude Red
Variable
> Date: Friday, January 14, 2000 9:59 PM
> 
> Dear All,
> 
> Attention is directed to NSV4189 Hydrae as a large amplitude red variable
> which appears to have been little studied in the past.  This star is
> currently again at maximum brightness.
> 
> In 1994 Eugene Brings of Mendocino, California noted variability of
NSV4189
> during a program to photograph red stars from the NSV catalogue where
> significant variation had been reported at infrared wavelengths.  A
visual
> study of this star by Peter Williams and Eugene Brings between 1994 and
the
> present has shown it to be an apparent Mira type variable of mean period
> near 465 days.  However, a considerable range of +/- 60 days has been
shown
> over the comparatively few observed cycles for a star of clearly long
> period.
> 
> A preliminary ephemeris for maximum brightness is JD2450180 + 465 days.
> 
> Average maximum magnitude from the 4 previously observed cycles is near
> 12.0 visual.  The present maximum of NSV4189 is near magnitude 11.0,
> noteably brighter than that previously observed.  Unfortunately, no
> reliable magnitudes are available for this field and we have therefore
used
> GSC magnitudes.  These appear to be somewhat in error (surprisingly) and
> perhaps one magnitude fainter than expected.
> 
> A brief paper on our observations of this star is under preparation for
the
> Publications of the VSS RASNZ and will be submitted after conclusion of
the
> present observing season in June 2000.
> 
> Please enjoy the current bright maximum of NSV4189.
> 
> NSV Catalogue details of NSV4189 are:
> 08h 38m 04s -14d 38'.3 (1950)
> Max 2.29 K
> Min 3.47 K
> Designation IRC-10202
> Spectrum M8
> 
> Regards
> 
> Peter Williams, Heathcote, NSW
> Eugene Brings, Mendocino, California
> 
> 
>

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