[vsnet-newvar 2930] (fwd) new CV candidates by Denisenko and Sokolovsky

[Taichi Kato]

From: "BigDen" <denis at hea.iki.rssi.ru>
Date: Tue, 13 Jul 2010 00:21:36 -0000
Subject: [cvnet-discussion] Call for observations of new faint CVs

Hello all!

I would like to point your attention towards the new cataclysmic varibles we have just published at astro-ph with my friend and colleague Kirill Sokolovsky. We have discovered eight cataclysmic variables and two probable optically violent variable quasars using just the photomeric data of USNO-B1.0 catalogue alone!

We were searching for the high-amplitude blue variable objects (with
range of variability more than 2m) within 30" of X-ray sources from ROSAT catalogue to the North of -10 declination and outside the SDSS coverage. Thus, 8 out of 10 new objects can be observed right now (two are actually circumpolar for the northern hemisphere folks). By coincidence, 4 of 10 new variable objects reside in Draco constellation! Bad news is that all our objects are quite faint, with the brightest at 15m in outburst. So they are definitely the targets for CCD observers. But the good news, again, is that virtually nothing is known about these objects! No type of variability, no orbital periods, no outburst interval, not even the exact variability range! So if you start following them up, you can discover a lot of new things.

The list of objects with the coordinates and 10'x10' color combined finder charts are available at my page:

http://hea.iki.rssi.ru/~denis/CV-USNO.html

The article is accepted to Russian Astronomy Letters. Meanwhile you can download the pdf or PostScript file from the archive of electronic preprints at this link:

http://arxiv.org/abs/1007.1798

I am already monitoring a couple of objects with the Bradford Robotic Telescope now that the Galaxy camera in back in operation. But since it was offline for almost half a year, the requests queue is very large at BRT. So I will be very grateful if some of you could add those stars to your monitoring programs!

Best regards, and Happy observing!

Den in Moscow