[vsnet-alert 21483] MASTER OT J205110.36+044842.2 past outbursts and ROSAT ID

[Denis Denisenko]

This 15.0m optical transient in Delphinus reported by MASTER team in
ATel 10790 (V. Shumkov et al.) is apparently a dwarf nova, most likely
of SU UMa type. There is ROSAT faint X-ray source formally 17" away,
but with a 21" error circle:

1RXS J205111.1+044829
0.0258+/-0.0092 cnts/s HR1=0.82+/-0.24 HR2=0.30+/-0.36

NEAT project (Teegarden et al., 2003) has observed this position on 19
nights from 2001 May 27th to 2005 Aug. 14th. 59 images are avaiable
from SkyMorph website at
https://skys.gsfc.nasa.gov/skymorph/skymorph.html with two outbursts
detected in 2001 and 2002:

MASTER OT J205110.36+044842.2
  20010527.4671  14.89CV  NEAT
  20010527.4758  14.93CV  NEAT
  20010527.4866  14.94CV  NEAT
  20010603.5284  15.72CV  NEAT
  20010603.5391  15.63CV  NEAT

  20020824.3398  15.72CV  NEAT
  20020824.3606  15.76CV  NEAT
  20020824.3902  15.63CV  NEAT

The star 1.6'E and 1.2'S of the variable was used as a reference with V=14.966.
Color-combined DSS finder chart:
http://scan.sai.msu.ru/~denis/J2051+0448-BRIR.jpg (10'x10' FOV).

May-June 2001 outburst was most likely a superoutburst with a ~0.1m
per day fading rate.
SDSS and PanSTARRS gri colors suggest a short orbital period:

SDSS J205110.35+044842.0
u=18.69 g=18.94 r=18.75 i=18.81 z=18.36

PSO J205110.352+044842.147
20 51 10.356 +04 48 42.11
g=19.58 r=19.46 i=19.04 z=19.07 y=18.81

Denis Denisenko