[vsnet-alert 19622] DDE 46: new SU UMa-type dwarf nova 22' from NSV 8494

[Denis Denisenko]

On Mar. 18th I have discovered a new variable on iTelescope T31 images of
the field centered at NSV 8494. New variable was designated DDE 46 and
reported in ATel 8842  <http://www.astronomerstelegram.org/?read=8842>. At
the moment of discovery it was still faint (17.9m), but it has brightened
by 1.4m (to 16.5m) 24 hours later. The brightening was reported in ATel
8845 <http://www.astronomerstelegram.org/?read=8845>. Here are unfiltered
magnitudes with the red zero point:

2016 Date UT    JD       Mag.
-----------------------------
Mar. 12.783 2457460.283 <19.0
Mar. 18.780 2457466.280 17.90
Mar. 18.783 2457466.283 17.85
Mar. 19.785 2457467.285 16.52
Mar. 19.788 2457467.288 16.53

Today (Mar. 21.67-21.75 UT) I have obtained 2 hours of unfiltered
photometry remotely with the same T31 telescope at Siding Spring. The
variable is showing superhumps with an amplitude about 0.4m (16.5-16.9m)
and a period close to 2 hr or a bit more. Time series from South Africa and
Chile or Argentina are urgently needed to determine the period.

If you have field of view larger than 25' from North to South, you can
cover two CVs simultaneously! NSV 8494 is likely a VY Scl-type variable
(anti-nova), as shown in ATel 8842.

DDE 46 coordinates: 17 19 24.03 -15 05 54.4
NSV 8494 position: 17 18 56.69 -15 27 33.6
Point your FOV at 17 19 00 -15 16 00 to cover both stars together. We still
have 2 or maybe 3 nights until the Moon comes too close to the field.

Preliminary light curve of DDE 46 for tonight:
http://scan.sai.msu.ru/~denis/DDE46-T31-LC-20160322.gif
NSV 8494 is showing slower variations with a smaller amplitude (about 0.1m
over 2 hours).
The photometric sequence for both stars is desired. If somebody has
observed the field after my call for observations in ATel 8842 and 8845,
please let me know.

Denis Denisenko
Sternberg Astronomical Institute of Moscow State University