[vsnet-alert 21982] Re: Vend S934: a possible bright (12.5-13.0mag) CV candidate in Cygnus?

FIDRICH Róbert fidusz@gmail.com via vsnet-alert vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp
Sat Mar 17 08:46:40 JST 2018


On CCD images made by Vikrant Kumar Agnihotri at March 16.9358 UT there 
is no bright object at the given position.
The blue star USNO A2.0 1425-09651911 seems to be in quiescence near 
18-18.5 mag.

Best,

Robert

2018-03-16 12:45 keltezéssel, FIDRICH Róbert írta:
> 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



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