Central Bureau for Astronomical Telegrams

CBAT "Transient Object Followup Reports"

PNV J18315791-5121498

PNV J18315791-5121498   2020 09 12.9712*  18 31 57.91 -51 21 49.8  14.2 C             Tel       9 0

2020 09 12.9712

Discovered by L. Amaral, E. Pimentel, C. Jacques, C. Colesanti, C. Barreto, I. Mussi, J. Ribeiro, M. Domingues, J. Amancio, P. Holvorcem, T. Napoleao on behalf of the Brazilian Transient Search - BraTS - at Observatorio Campo dos Amarais, Bilac, Brazil in three frames with 60 seconds exposure using a 306mm f/4 reflector + CCD with magnitude 14.2 under limiting magnitude 19.0. Nothing is visible at this location on the previous frame (limiting mag = 19.0) taken on 2020 July 26.1389 UT.

2020 09 13.9344

Mag. 13.4 (unfiltered) and J2000.0 position end figures 57.91s, 49.8" in a 60-s exposure using a 306mm f/4 reflector + CCD. Observers L. Amaral, E. Pimentel, C. Jacques, C. Colesanti, C. Barreto, I. Mussi, J. Ribeiro, M. Domingues, J. Amancio, P. Holvorcem, T. Napoleao on behalf of the Brazilian Transient Search - BraTS - at Observatorio Campo dos Amarais, Bilac, Brazil.

2020 09 14.26

The progenitor is probably the blue star Gaia DR2 6655529288079298688 with position end figures 57.899s in RA and 49.975" in DE (equinox J2000.0, epoch J2015.5; Gmag. 20.55, BPmag. 20.4, RPmag. 20.1), which is 0.2" SSW of the reported position of the transient. Other designations are GSC2.3 SAPQ085138 (Fmag. 20.0, Bjmag. 20.8) and GALEX J183157.9-512148 (FUVmag. 21.5, NUVmag. 21.6). No brightenings were observed by the ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017PASP..129j4502K) since 2014 May 17; the latest observation is 2020 Sept. 7.721 UT, fainter than gmag. 16.5; complete light curve and data at https://asas-sn.osu.edu/light_curves/e8b4e159-50ce-4a1d-8057-46c0fdeb484b —— Dwarf nova outburst? Time-resolved photometry is recommended. Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)