[vsnet-alert 24205] KIC 11390659 = 1RXS J185831.1+491434 outburst

[Kirill Sokolovsky]

KIC 11390659 (UG) https://www.aavso.org/vsx/index.php?view=detail.top&oid=297526
was found in outburst on the NMW survey images
2020-04-19.8800  2458959.3800  CV=12.96
Our previous observation of this field was on
2020-04-16.8738  2458956.3738  CV>13.5

ASAS-SN lightcurve 
https://asas-sn.osu.edu/light_curves/401ad310-17b7-45f5-bb0e-751362382656

Best wishes,
Kirill Sokolovsky and Stanislav Korotkiy


Previous vsnet-alert messages regarding this object:
http://ooruri.kusastro.kyoto-u.ac.jp/mailarchive/vsnet-alert/18705

===

KIC 11390659 = KIC J185830.91+491432.7 outburst

    ASAS-SN detection.  This object has a suspected
orbital period below the period gap.
Such a bright outburst was not recorded by Kepler.
Observations are encouraged.

KIC11390659	18:58:30.91	49:14:32.70	16.26	2015/06/08 13:06	57181.54589999979	13.36	13.33	57181.54752

KICJ185830.91+491432.7 20150608.546 13.36V ASN
KICJ185830.91+491432.7 20150608.548 13.33V ASN


http://ooruri.kusastro.kyoto-u.ac.jp/mailarchive/vsnet-alert/15921

===

Regarding KIC 11390659 = 1RXS J185831.1+491434 = GALEX J185830.9+491432.

This variable shows a really interesting behavior with no regular
pattern of outbursts. Kepler light curve from Quarters 6-7 shown at
Fig. 11 of the paper by Howell et al. (arXiv:1302.3975) *might* remind
that of ER UMa-type dwarf novae, while Quarters 9-11 and 14-15 are
looking rather different. Also, quoting the paper above:

> the periods are not well established but the common solution for all 3 lines
> from the blue channel in the Palomar data are in the range of 106-109 min

(from the analysis of Balmer line velocities on Page 9), however
caption to Fig. 11 says:

> A power spectrum of this light curve showed no significant periods including any near 107 minutes.

Well, but if you check short cadence from Quarter 14 and limit the
period range to 0.04-0.10, you will find a peak on the periodogram
that stands out at 0.076775d with power 90.0 (other peaks on the power
spectrum have values of 34.5, 31.2 and lower).

Thus, it is possible that the period is 110.56 minutes - formally
outside the suggested range of 106-109 min, but close to it.

Also, I have checked MASTER data for the last ~1.5 years, and the
object was never found brighter than 15.2 unfiltered magnitude. The
last observations by MASTER-Amur were obtained on June 28 UT:

KIC 11390659 = 1RXS J185831.1+491434
   20130628.686  160C  MASTER-Amur
   20130628.723  164C  MASTER-Amur

V=14.8 value reported by Kris Stanek in [vsnet-alert 15906] seems to
be unusual, indeed!

Denis Denisenko