[vsnet-alert 16452] Re: ASASSN-13db

[Denis Denisenko]

On Tue, Sep 24, 2013 at 19:25+0400 I wrote:

>> ASASSN-13db         05:10:11.08   -03:28:26.3    2013-09-24.5     15.27
>
> Interesting case! Obviously the *blue* star goes into outbursts which
> is 4" North of the red star. See the color-combined finder chart:
> http://master.sai.msu.ru/static/OT/J051011-032826-BRIR5x5.jpg

I have to admit I was wrong! The outburst is positionally consistent
with the red star, as Kris Stanek originally reported. I have checked
MASTER-Amur images of 2011 Jan. 22. Aligning and blinking V-band image
with DSS or SDSS clearly shows the southern (red) component has
brightened. Coordinates formally measured by the robot are 05 10 11.00
-03 28 26.1 from V image and 05 10 11.01 -03 28 26.3 from the Red one,
identical to the red dwarf SDSS J051011.00-032826.2. That makes the
case even more intriguing!

Near-infrared magnitudes of 2MASS 05101100-0328262 J=14.13(3),
H=13.54(3), K=13.11(3) correspond to M7-M8 red dwarf.

> Previous outburst was serendipitously observed by MASTER-Amur
> telescope 2.5 years ago
>
> ASASSN-13db = CSS J051011.0-032826
>   20110122.521  13.24V  MASTER-Amur
>   20110122.553  13.11R  MASTER-Amur

Converting the date into Julian Days, 2011 Jan. 22.521 UT corresponds
to JD 2455584.021. CRTS photometry during the outburst mentioned by
Kris Stanek is as follows (dates are MJD = JD-2400000.5):

55541.31833 15.06
55541.33624 15.19
55541.34526 15.08
55565.32345 15.06
55565.33103 15.10
55565.33860 15.09
55565.34622 15.14

The last Catalina observation before the outburst was on
MJD=55508.39045 (17.29m), then there's a half-year long gap until
MJD=55855.42951 (17.41m). No additional outbursts were detected in 8
years of Catalina Sky Survey. Also, there were no outbursts in the
earlier NEAT data from Dec.2000 to Feb. 2003. Truly amazing and
mysterious object!

Denis Denisenko