NSV 19680

[Patrick Wils <patrickwils@yahoo.com>]

John Greaves notes that NSV 19680 (one of the eclipsing binaries I
mentioned in my previous post) also appears to be a bright xrays
source, a faint IRAS source, and a FIRST radio source (20 cm, or HI). 
He also notes that there doesn't _appear_ to be a field galaxy there
according to catalogues and/or DSS images, so that there are definitely
interactive stellar atmospheres and gas streams involved!

The Hipparcos data (HIP 64732) show 0.1 mag "variation", and Koen &
Eyer (MNRAS 2002) derived a frequency of 0.204 c/d from them (which is
an alias of the double of 1.402 c/d, which I gave in my previous post -
you need to multiply by 2, since I counted two minima per cycle).  They
give a 25 millimag amplitude, which may be challenging.

ASAS3 online data (at the URL
http://www.astrouw.edu.pl/cgi-asas/asas_lc/131603-0540.1) shows a 0.8
mag amplitude in V, with the star mostly at maximum near V=7.6, and
with all the minima in the first half of the graph.  This sort of
pattern can be noted in the ASAS data of other stars as well (e.g. QS
Ser), so there is a problem with the data, clouds or the reduction of
(some of) the images.  Probably everything below 7.8 should be thrown
out as erroneous (including the negative data point - due to saturation
?), and because of this you get to be suspicious of the other points as
well.  In any case, I didn't find a trace of the period mentioned
above.

Patrick



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