[vsnet-alert 20057] DDE47 (eclipsing CV in outburst, Sgr) ATEL

[Taichi Kato]

DDE47 (eclipsing CV in outburst, Sgr) ATEL

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ATEL #9342							     ATEL #9342

Title:	New Eclipsing Cataclysmic Variable in Sagittarius
Author:	D. Denisenko (Sternberg Astronomical Institute, Lomonosov
		Moscow State University)
Queries:	d.v.denisenko at gmail.com
Posted:	8 Aug 2016; 18:31 UT
Subjects:Optical, Cataclysmic Variable, Transient, Variables

During the observations of an area centered at NSV 11918 with iTelescope.Net's
T31 instrument in Siding Spring, Australia (0.51-m astrograph + 3kx3k CCD
with 55'x55' FOV), new optical transient was serendipitously discovered
on 2016 Aug. 08.46 UT. The object is located at the following coordinates:
R.A. = 19 22 38.80, Decl. = -31 16 28.6 (J2000.0). It was designated DDE
47 according to the numbering scheme used before (see also ATel #8842).

During 1.2 hours of observations from 11:02 to 12:14 UT on 2016 Aug. 08
the object has shown variability by 0.8 mag (17.8-18.6) with a short eclipse
before the end of the series at about 2016-08-08.505 UT. A total of fifty-seven
unfiltered 60-sec exposures were obtained. The light curve from the images
combined by three (resulting in 19 points with the effective exposures
of 180 sec) is uploaded to http://scan.sai.msu.ru/~denis/DDE47-T31-LC-20160808.jpg
(the nearby star CMC15 192236.0-311646 was used as a reference with V=15.50).

Comparison of T31 images showing the new variable at maximum and minimum
light with the 1992-05-29 DSS Red plate is shown at http://scan.sai.msu.ru/~denis/DDE47-T31-DSS-anim.gif
and the color-combined DSS finder chart (sum of two IR, two Red and two
Blue plates) centered at the position of new variable is available at http://scan.sai.msu.ru/~denis/DDE47-JRIR5x5.jpg
(2x zoom). The object is marginally visible at one Blue plate (limiting
mag about 21.5), but can not be detected on other plates. No previous outbursts
were detected by Siding Spring Survey checked via CRTS website or on NEAT
images checked at SkyMorph. The object is a new eclipsing cataclysmic variable
(most likely a dwarf nova, but a polar in the high state is not excluded).
Follow up photometry is needed to determine the orbital period and to monitor
the future behavior.

Variable stars discovered by DDE: http://scan.sai.msu.ru/~denis/VarDDE.html