[vsnet-alert 14924] Re: Possible bright CV in Peg? - PNVJ23272715+0855391

Sebastián Otero varsao at hotmail.com
Fri Sep 14 08:51:35 JST 2012

> An object with such a large outburst amplitude should most likely be a
> WZ Sge-type DN, this is why it is really surprising that it had an
> outburst just 12.5 years ago. I made a simple virtual experiment with
> NSVS data checking the light curve of a nearby star 2MASS
> 23272242+0855291 (J-K=0.74) 1.2' away, and it also has an outburst in
> ROTSE-I data: http://skydot.lanl.gov/nsvs/star.php?num=11851348&mask=32004
> (though on the different date). Not that I don't trust NSVS - after
> all, I have found there a real outburst of RX J2319.6+3647 blended
> with a 14.2m star 18" away. What I want to say is: perhaps two
> outlying points on a single night are not an "ironclad" evidence of
> the outburst.

Very interesting.
I think you're right. I had not noticed such large amplitude outliers 
before. Since they come in pairs, wrong observations usually have a large 
difference between each other (in the pair). But here it doesn't seem to be 
the case. Even the error figures are small in your example.

Furthermore, there is a confirmation of the outburst not being real in the 
case of your star:
Almost simultaneous observations in this synonym showing no outburst.

I notice that the data after 2451532 is brighter here too. No observations 
here at the date of the outburst (1565) in the NSVS data for the CV position 
though so a comparison is not possible.
This brighter star is 71" away from the dwarf nova so contamination is still 
possible although unlikely.

In any case, the blended NSVS light curve of the two stars in the area of 
the CV shows a brightening of two magnitudes. It might be a coincidence or 
not. Your finding in the other star has proved that it can't be confirmed, 
but can't be ruled out either.


Sebastian Otero
VSX Team
American Association of Variable Star Observers

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