Central Bureau for Astronomical Telegrams

CBAT "Transient Object Followup Reports"

TCP J18013892-3559400

TCP J18013892-3559400   2018 06 13.6326*  18 01 38.92 -35 59 40.0  12.7 U             Sgr       8 1

2018 06 13.633

Discovered by T. Kojima, Gunma-ken, Japan, who found this on three frames (limiting mag.= 13.8) taken by Canon EOS 6D + 200-mm f/3.2 lens and the pre-discovery image on three frames taken on 2018 June 12.645 UT. Nothing is visible at this location on two frames taken on 2017 June 2.668 and 2018 May 21.666 UT (limit mag.= 13s). He writes there is a star of 2MASS 18013898-3559470 (Kmag= 8.588).

2018 06 16.61

The abovementioned star 2MASS J18013898-355947 (Gaia DR2 position end figures 38.986s, 47.01") is 7.1" SSE of the reported position of the transient. According to the ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017PASP..129j4502K) light curve for 2MASS J18013898-355947 there is a periodic variation (period about 170 days), V magnitude range 13.0-15.2; the latest available observation is 2018 May 22.309 UT, V= 13.3 mag: https://asas-sn.osu.edu/light_curves/e9998657-8516-4612-8b7a-ee0090d1cc33. Obviously a pulsating variable. --- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

2018 06 16.626

K.Itagaki, 0.5-m f6.8 : 18 01 38.98 -35 59 46.7 Mag.=11.4

2018 06 18.338

Mag. B= 14.30, V= 12.65 ,Ic= 10.96, position end figures 38s.97, 47".2 observed by K. Yoshimoto, Yamaguchi-ken, Japan, using 0.43-m f/6.8 Mayhill reflector + CCD + f/4.5 focal reducer, remotely. An image at http://orange.zero.jp/k-yoshimoto/TCP-J18013892-3559400.jpg.