Central Bureau for Astronomical Telegrams

CBAT "Transient Object Followup Reports"

TCP J16475765-3102582

TCP J16475765-3102582   2020 03 06.7994*  16 47 57.65 -31 02 58.2  12.7 U             Sco       9 0

2020 03 06.799

Discovered by Tadashi Kojima, Tsumagoi,Gunma-ken, Japan, on three frames under limiting mag.= 13.5 taken by Canon EOS 6D + 200mm f/3.2 lens. Nothing is visible at this location on two frames taken on 2020 Mar 2.789 UT with 200mm lens under the limiting mag.= 13.5

2020 03 06.799

Discovered by Tadashi Kojima, Tsumagoi,Gunma-ken, Japan, on three frames under limiting mag.= 13.5 taken by Canon EOS 6D + 200mm f/3.2 lens. Nothing is visible at this location on two frames taken on 2020 Mar 2.789 UT with 200mm lens under the limiting mag.= 13.5

2020 03 06.4015

Possibly a flare of 2MASS J16475750-3102570, which is 2.1" WNW of the reported position of the transient. Gaia DR2 position end figures for this red star are 57.498s and 57.49" (equinox J2000.0, epoch J2015.5; Gmag. 14.53, parallax 7.3637 ± 0.0744 mas, distance 135.3 ± 1.4 pc). Other designations are USNO-A2.0 0525-24062279 (Bmag. 16.4, Rmag. 14.3), USNO-B1.0 0589-0427028, GSC2.3 S8EZ009138 (Vmag. 15.6, Fmag. 14.8, Nmag. 13.1), WISE J164757.50-310257.2, SMSS J164757.50-310257.3, PSO J164757.503-310257.319 (gmag. 16.3, rmag. 15.3, imag. 13.9). No brightening recorded in recent ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017PASP..129j4502K) data: https://asas-sn.osu.edu/light_curves/e89d543b-4b54-422a-82e0-3d6093028a6d --- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

2020 03 06.80134

Minoru Yamamoto, Okazaki, Aichi, Japan, reported his independent discovery of this TCP to NAOJ on 2020 Mar. 6.870 UT. He discovered it on a frame taken on 2020 Mar. 6.80134 and 6.80156 UT using CANON EOS5D Mark2 + 180mm F3.5 lens. He reported the position RA 16 47 57.35, Dec -31 02 55.4 (+/- 5.0", 2000.0) and magnitude 11.8 (limiting mag 12.4). This object was not shown on a frame taken on 2020 Mar 2.81086 UT (limiting mag 12.4).

2020 03 06.838

Mag=13.0 Tadashi Kojima confirmed by same instrument

2020 03 07.3397

The latest ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017PASP..129j4502K) data indicate that this transient is still bright: 2020 March 6.401 UT, gmag. fainter than 16.78; 7.340, gmag. 15.46; 7.342, 15.57. These magnitudes are fainter than those reported above (mag. 12–13 CR), so the transient seems to be reddish (and/)or fading. Complete ASAS-SN Sky Patrol light curve at https://asas-sn.osu.edu/light_curves/ff569627-8d0a-44ef-9d50-c70bda6ef94b - The progenitor candidate proposed above by me is included in "3D mapping of young stars in the solar neighbourhood with Gaia DR2" (2018A&A...620A.172Z) and also in a catalogue of pre-main-sequence (PMS) members of the Scorpius–Centaurus Association (Sco OB2) (2019A&A...623A.112D). Precise astrometry, spectroscopy, and multiband photometry of the transient are urgently required. --- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

2020 03 07.0023

Photometry results were 15.092V (0.035) with 0.25m iTelescope.net reflector Mayhill, New Mexico, US. Position end figures were 57.53 and 57.6 in R.A. and Dec. -- Robert Fidrich (Budapest, Hungary)

2020 03 07.00

Position end figures (based on Gaia DR2 data) for 2MASS J16475750-3102570 for equinox J2000.0 and the current epoch are 57.50s in RA and 57.6" in DE; the position reported by Róbert Fidrich is only 0.03s (i.e. 0.4") to the E). --- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

2020 03 07.5023

Correction: Photometry results were 15.092V (0.035) on March 7.5023UT and 12.772 I (0.008) on March 7.5046UT with 0.25m iTelescope.net reflector Mayhill, New Mexico, US. Position end figures were 57.51 and 57.6 in R.A. and Dec. -- Róbert Fidrich (Budapest, Hungary)

2020 03 08.3309

The transient (an unusually long red dwarf flare?) was fainter than gmag. 16.3 on March 8.331 UT, according to the latest ASAS-SN Sky Patrol data at https://asas-sn.osu.edu/light_curves/98af1cb8-e096-41f3-a588-259161abf710 --- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)