[vsnet-newvar 1769] NSV 19483 identity is _not_ clear

[jg@jgws.freeisp.co.uk]

The NSV supplement gives the following reference for this object :-

E.J.Grayzeck, AJ 83, No.11, 1390, 1978

Which gives RA 12h 41.9m -65d 00' B1900 for star 114 in TABLE I, which
is GSC 8996 1474, and star 114 is obviously the one the NSV intends to
mention, as both the NSV and the paper identify it as an EA star of
8.42d period (TABLE II of the paper). The NSV also gives a B-V of 2.00
for this star.

HOWEVER.  The chart in the same paper for star 114, at (url will need
unwrapping)

http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1978AJ.....83.1390G&db_key=AST&page_ind=1&plate_select=NO&data_type=GIF&type=SCREEN_GIF

appears to have no connection with the true field as shown by survey
plates and/or plotting of GSC2.2 and/or USNOB1.0 objects.  Although
differing scales and limiting mags always make such things problematic,
even rotation of the field through 90 degree quadrants doesn't help.


Now. The original survey intent of the paper authors was to detect long
period Cepheids.  So not much detail is given with respect to this
suspected eclipser.

There are such things as "cool Algols" which are pairs of late star
eclipsing binaries, but we have other problems.

It's an IRAS source, and quite red using NOFS archive plates
(unfortunately there are no contemporaneous plates).  This is not
necessarily characteristic of a cool Algol.  Further, there is no xray
source, as could be expected from a cool Algol.

FINALLY, examination of archival SERC/AAO survey plates show that GSC
8996 1474 shows variability on both the two blue and two red plates
consistent with a low amplitude LPV.

Meanwhile, GSC 8996 0455 is a blue star, of Tycho BT-VT of -0.03, which
would be somewhat more consistent with any EA type star.

Archive plates show no evident variation for GSC 8996 0455, but it is
mostly overexposed on all plates.

CONCLUSION : It is difficult to tell whether the original RA and Dec
given for star 114 in AJ 83, 1390 is for the star meant, or whether the
original authors became confused and measured the wrong star. At visual
wavelengths, at least, the two are a fairly similar same declination
pair.  The star they seem to have measured is a quite red IRAS source
and does not fit the _usual_ type of an EA star, however, who is to say
that their original identification of type was correct, given the lack
of details in the paper.  The finder chart appears not to relate to the
field, so there is no easy way to double check.

It is not clear whether the authors meant this star (GSC 8996 1474), but
got the identification of variability type wrong, or meant GSC 8996 0455
and got the co-ordinates wrong.

Certainly, it appears from several considerations (separate posting to
follow) that TbrV0149 is GSC 8996 1474, so the question resolves to :
are there two variables here, or only one?  If only one, NSV 19483 =
TbrV0149, if two, it does not.


John Greaves

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