[vsnet-alert 14632] New dwarf nova in UMi MASTER OT J143857.37+703523.1

[Denis Denisenko]

MASTER-Amur has discovered an outburst of the previously unknown dwarf
nova in Ursa Minor MASTER OT J143857.37+703523.1 to 12.9m on 2012 May
30.717 UT (see ATel #4143,
<http://www.astronomerstelegram.org/?read=4143>). The object is
identical to the 19-mag star USNO-B1.0 1605-0102553 (R.A. = 14 38
57.462, Dec. = +70 35 22.97, pmRA=-32 mas/yr, pmDE=12 mas/yr) and to
the ultraviolet source GALEX J143857.4+703523 (NUV=20.64+/-0.17).
There is nothing at this position in ROSAT, 2MASS, GCVS catalogues and
in AAVSO VSX.

Follow-up observations on 2012 June 01.64 UT with the same telescope
show the object has faded by 1.4m in two days, to 14.3 mag. The new
variable is likely of UGSU or UGWZ subtype. Photometric follow-up is
encouraged.

10'x10' color-combined (BRIR) DSS finder chart with the USNO-A2.0
magnitudes of several comparison stars is uploaded to
http://master.sai.msu.ru/static/OT/J143857+703523-comps.jpg

Denis in Moscow

P.S. Yet another cataclysmic variable once thought to be a quasar!
(Simbad lists it as Q? despite the obvious proper motion between two
Palomar epochs).