[vsnet-alert 17069] PTF1 J071912.13+485834.0 outburst

[Denis Denisenko]

MASTER-Amur has caught this ultra-short period (26.77 min) AM CVn-type
dwarf nova in Lynx at the early stage of outburst:

PTF1 J071912.13+485834.0
  20140318.478  <182C   MASTER-Amur
  20140320.482   158C   MASTER-Amur
  20140320.553   159C   MASTER-Amur
  20140320.569   157C   MASTER-Amur

It is not clear whether this is a normal outburst or a superoutburst.
The object was as bright as 15.1m on 2013 Nov. 21 MASTER-Amur
unfiltered images. According to the discovery paper by D. Levitan et
al. (arXiv:1107.1209), superoutburst recurrence time in this system
varies from 65 to more than 78 days. Orbital period is well determined
as 0.01859d (26.77+/-0.02 min), but P_sh was not measured even to 0.1
min accuracy.

Light curve from Catalina Sky Survey since December 2005
http://nesssi.cacr.caltech.edu/cgi-bin/getcssconedb_id.cgi?ID=1149027025401&OUT=csv&SHORT=short&PLOT=plot
shows a dozen outbursts between 16-17m and two outbursts brighter than
16m: on 2009 Feb. 27 (15.6m) and 2011 Jan. 02 (15.8m).

The star was in outburst on 1953 Feb. 14 POSS-I blue and red plates
and on 1983 Nov. 07 Quick-V plate (Vmag=15.94 in GSC 2.3.2). Entries
in USNO catalogues:
USNO-A2.0 1350-07063768 (07 19 12.10 +48 58 34.6 R=16.2 B=15.6)
USNO-B1.0 1389-0185187 (07 19 12.115 +48 58 35.14  pmRA=4 pmDE=10
B1=15.96 R1=16.22 B2=19.14 R2=18.54 I=18.37)

This area of sky is not covered by SDSS and GALEX. Color-combined DSS
finder chart is uploaded to
http://master.sai.msu.ru/static/OT/J071912+485834-BRIR5x5.jpg

Denis Denisenko
Member of MASTER team at SAI MSU

P.S. A number of recently discovered outbursting AM CVns leads to the
thought that there should be a couple of such systems hiding among
more than 250 MASTER CVs, especially among the objects outside SDSS
coverage. A good candidate can be recently discovered MASTER OT
J200904.69+825153.6, see [vsnet-alert 17015] and ATel #5974.