[vsnet-alert 15387] EV UMa aka 1RXS J130753.6+535137 back to high state

[Denis Denisenko]

According to the recent survey images by MASTER-Amur robotic
telescope, this polar (magnetic CV of AM Her type) is again in the
high state:

EV UMa
  20130108.868 <186C  MASTER-Amur
  20130120.743 <183C  MASTER-Amur
  20130204.738  164C  MASTER-Amur
  20130204.770  161C  MASTER-Amur
  20130214.548  162C  MASTER-Amur
  20130214.580  168C  MASTER-Amur

This are the first positive detections of this variable by MASTER-Amur
robotic telescope since the beginning of survey in early 2010.
According to Catalina Sky Survey, EV UMa was in the high state
(16.3-17.5m) in 2005-2009 followed by the low state (19.0-<21.0)
during 2010-2012. The CRTS light curve of this object is available
here:
http://nesssi.cacr.caltech.edu/catalina/20010514/105141550424100070p.html
(last observation at 19.6m dated by 2012 May 29).

The orbital period of this CV is well known. It is 0.05533887d (79.688
min). The star is identical to SDSS J130753.86+535130.5 (u=16.86
g=16.51 r=16.85 i=16.92 z=16.99), see
http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237658916922392619

Denis Denisenko
Member of MASTER team at SAI MSU