[vsnet-alert 22013] TCP J21290156+3631056: new transient (11.5 mag) in Cygnus

Fri Mar 23 07:56:49 JST 2018

TCP J21290156+3631056  (UG:)

RA 21h29m01.56s, DEC +36°31'05.6" (J2000.0)
2018 Mar. 22.7846 UT, 11.5 mag (CCD, unfiltered)
Discoverer: Tadashi Kojima (Gunma-ken, Japan)

2018 03 22.785 UT
Discovered by T. Kojima, Gunma-ken, Japan, on three frames with five second
exposure using Canon EOS 6D digital camera + 200-mm f/3.2 lens under the
limiting mag = 13.8, who writes nothing is visible at this location on the
previous frame (limit mag = 13.5) taken 2018 Mar. 16.783 UT. There is a star
(mag = 16.7) at 01s.72 and 06".9. 

2018 03 22.93 UT
The abovementioned star of 16.7 mag is USNO-A2.0 1200-18025481. There are
many other designations for this star (G= 17.19 mag in Gaia DR1), e.g.
USNO-B1.0 1265-0493972, GSC2.3 N359016841 (V= 17.39 mag), XPM 253-0794263,
2MASS J21290156+3631049, 1RXS J212902.0+363103.
No previous outbursts or eruptions were recorded by the ASAS-SN Sky Patrol
(Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017PASP..129j4502K)
between 2015 March and 2017 November (latest available observation
2017-11-22.247 UT):
https://asas-sn.osu.edu/light_curves/3083fd37-af79-48f5-9509-6e5e1bb30b83
--- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

Follow-up reports:
http://www.cbat.eps.harvard.edu/unconf/followups/J21290156+3631056.html

Spectroscopy, time-resolved photometry, and precise astrometry are urgently
required.

Clear skies,
Patrick