[vsnet-alert 15193] New interesting CVs by MASTER

[Denis Denisenko]

Sergey Shurpakov has discovered three new CVs on the images from
MASTER-Amur robotic telescope in last two days which are worth
mentioning on this list. One is likely a new eclipsing polar in Ursa
Major with the large orbital variability (16.4-<18.8), and two others
are dwarf novae about 16m.

MASTER OT J132104.04+560957.8 - polar in a high state?
ATel 4662 <http://www.astronomerstelegram.org/?read=4662>

The object was faint (~21m) on Palomar plates and SDSS images, but has
brightened to ~16.5 at maximum around 2007 (according to Catalina Sky
Survey data) and remains in the high state ever since. SDSS magnitudes
are:
SDSS J132104.01+560958.1 u=22.30 g=21.65 r=21.25 i=20.65 z=20.11

Object is showing the fast variability changing its brightness by 2
mag in 30 minutes on MASTER-Amur images (from 18.4 to 16.4), as well
as in CSS data. Eclipses are very likely. Probably it has a short
period about 99 minutes. Photometric time series are very desirable!

MASTER OT J191156.83+403101.6 - dwarf nova in Lyra with outburst
amplitude at least 5m
ATel 4664 <http://www.astronomerstelegram.org/?read=4664>

Magnitude on outburst images:
  20121220.387  164C  MASTER-Amur
  20121220.418  167C  MASTER-Amur
Nothing on DSS plates to the limiting magnitude ~21.5. Color-combined
finder chart: http://master.sai.msu.ru/static/OT/J191156+403101-BRIR5x5.jpg

MASTER OT J202225.43+511248.0 - dwarf nova in Cygnus with outburst amplitude ~6m

Magnitude on outburst images:
  20121220.446  157C  MASTER-Amur
  20121220.478  157C  MASTER-Amur
Faint blue star (mag~21.5) is visible on DSS plates:
http://master.sai.msu.ru/static/OT/J202225+511248-BRIR5x5.jpg

Photometry is encouraged for both objects, too.

Denis Denisenko