[vsnet-alert 21981] Vend S934: a possible bright (12.5-13.0mag) CV candidate in Cygnus?

Fri Mar 16 20:45:49 JST 2018

Dear Friends,

I've found a possible CV candidate (Vend S934 interim name) my CH Cyg 
images made 2018 March 15.2033 UT at the following preliminary position:

19:22:52.13 +53:36:19.8 (J2000.)

The brightness of Vend S934 measured by VaST was 12.4TG (maybe a bit 
fainter). Unfortunately this object was quite close to the magnitude 
limit, thus I'm not 100% sure it was a real object. There was nothing 
visible on my reference images take on 15 September 2017 with a limit 
around 14.5 (or fainter).

There is a ~18.5 mag blue star only 8.5" from this position:

USNO A2.0 1425-09651911

19 22 51.98 +53 36 11.5 (J2000.0)

Taking into account that the astrometry might be not perfect since Vend 
S934 lies near the edge of my DSLR images, if it's a real object, it 
might be an outburst of this 18.5 mag star, which is also a GAIA source.

The ASAS-SN light curve for the position of this blue star show several 
short outburst:
https://asas-sn.osu.edu/light_curves/7d3ce0f4-4d9d-4749-af2b-79309829b433

There is a question however whether it's a real light curve or a dwarf 
nova or the "outbursts" are just an artifact caused by a 9th magnitudes 
star 1.2" from this position.

Unturtunately tonight there was raining both in Hungary and at the 
iTelescope.net facility in Spain. The sky was cloudy at the site of one 
of my friends in India, and the roof of New Mexico facility of 
iTelescope net is closed (probably because of the strong wind), thus I 
was not able to make confirmatory images.

Therefore I would like to ask anyone to make a follow-up observation in 
order to confirm whether it was a real outburst of this 18.5 mag blue star.

Thanx for your efforts,

Robert Fidrich
HAA/VSS
Vendégcsillag-kereső (Guest Star Hunter) team