[vsnet-alert 16054] New old CV in Andromeda by MASTER

[Denis Denisenko]

A month ago 16-year old high school student Anastasia (Nastya)
Lazareva has discovered a ~14.5m cataclysmic variable in Andromeda
MASTER OT J015016.17+375620.5 which was missed in several outbursts by
MASTER, Catalina (and maybe ASAS-SN). The object was found during the
intentional search for the "undiscovered" optical transients in
MASTER-Amur database which fall inside the 30" circles around
unidentified faint ROSAT sources. This star is located 11" from 1RXS
J015017.0+375614 (flux 0.0179+/-0.0096 cnts/s, hardness ratios
HR1=1.00+/-0.67, HR2=0.10+/-0.50). It varies from 19.1 to 14.3
unfiltered magnitude. Outbursts in MASTER-Amur database:

MASTER OT J015016.17+375620.5 = 1RXS J015017.0+375614
  20121128.591  14.24  MASTER-Amur
  20121128.623  14.27  MASTER-Amur
  20130107.400  14.78  MASTER-Amur
  20130107.431  14.92  MASTER-Amur

The discovery paper (to be published in Peremennye Zvezdy) was
uploaded to arXiv last night:
http://arxiv.org/abs/1307.6855
New Cataclysmic Variable 1RXS J015017.0+375614 in Andromeda
A. Lazareva, N. Voroshilov, D. Denisenko, A. Kuznetsov, E. Gorbovskoy,
V. Lipunov

The object at quiescence is identical to the ~19m star:
USNO-A2.0 1275-01092522  01 50 16.20 +37 56 19.1  R=18.1 B=18.5
USNO-B1.0 1279-0035859  01 50 16.183 +37 56 19.14 B1=19.00 R1=18.33
B2=19.09 R2=17.24 I=16.89
GALEX J015016.1+375619 FUV=18.58+/-0.08 NUV=18.12+/-0.05
2MASS 01501618+3756189 J=15.38+/-0.05 H=15.18+/-0.09 K=14.79+/-0.09
(likely caught in another outburst by 2MASS).

The recent observations by MASTER-Kislovodsk show the star was in
outburst again 6 nights ago:

MASTER OT J015016.17+375620.5 = 1RXS J015017.0+375614
  20130719.992  15.33  MASTER-Kislovodsk
  20130720.024  15.45  MASTER-Kislovodsk

In general, the archival light curve by Catalina Sky Survey looks like
that of an UGSU dwarf nova with 3 bright outbursts in Dec. 2005, Nov.
2007 and Oct. 2010 to 15.3-14.8m and several brightenings to 16-17m.
However, the star seems to spend too little time at minimum light
(~19m). In any case, the further monitoring is needed in order to make
the final classification of this "new old" CV. The object will be in
opposition with the Sun in October.

Denis Denisenko
Member of MASTER team at SAI MSU
Tutor of Astronomy project at International Research School