Central Bureau for Astronomical Telegrams

CBAT "Transient Object Followup Reports"

PSN J21040470+4631129

PSN J21040470+4631129   2019 07 12.4900*  21 04 04.70 +46 31 12.9   9.2 U             Cyg       9 0

2019 07 12.190

Discovered by Hideo Nishimura, Shizuoka-ken, Japan, on three frames using Canon EOS 6D Digital camera + 200-mm f/3.2 lens under the limiting mag = 14.5, who writes nothing is visible at this location on a frame taken on 2019 July 10.502 UT with the limit mag.= 15s and there is a candidate star (mag = 17) on DSS. A image will be provided later.

2019 07 12.490

A discovery image at http://www.oaa.gr.jp/~oaacs/image/PSNinCyg2019.jpg

2019 07 12.61

This transient does not look like a "possible supernova", but is likely a nearby dwarf nova outburst. I strongly recommend to use the designation TCP J21040470+4631129 instead of PSN J21040470+4631129. --- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

2019 07 12.61

The likely (blue) progenitor (supposedly Nishimura-san's mag. 17 candidate star) is USNO-A2.0 1350-13375367 (Bmag. 17.7, Rmag. 17.2) with Gaia DR2 position end figures 04.688s, 13.75" (equinox J2000.0, epoch 2015.5, Gmag. 17.77, parallax 9.1337 ± 0.1156 mas (distance 109.2 ± 1.4 pc)). Other designations are USNO-B1.0 1365-0394214, GSC2.3 N31X108363 (Fmag. 15.71, Bjmag. 17.76, Vmag. 18.34), PSO J210404.693+463113.906 (gmag. 18.20, rmag. 18.01), IPHAS J210404.68+463114.0. No outbursts were recorded by the ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017PASP..129j4502K) between 2015 March 20 and 2019 July 9; complete light curve at https://asas-sn.osu.edu/light_curves/56580af1-4b5a-4270-b96b-b77ef1ea8739. The transient is probably a dwarf nova outburst with an amplitude of at least 9 magnitudes (WZ Sge type?). Spectroscopy as well as multiband and time-resolved photometry are strongly recommended. --- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

2019 07 12.523

Yes, Suspected object type was mitaken, this is PNV. S. Kaneko, Shizuoka-ken, Japan, reports the following magnitudes with Canon EOS 6D Digital camera + 200-mm f/3.0; 2019 July 12.523 UT, mag.= 8.9, July 12.524 UT, mag.= 9.0.

2019 07 12.86845

Observation of this transient object was made on 2019 07 12.86845 by Andrea Mantero at Bernezzo Observatory (MPC C77) Cuneo, Italy, with a telescope 0.25 m. f/4 + V filter. Performed photometry returns a value of 8.592 +/- 0.004 V magnitude(reference v mags from APASS ).Astrometry RA= 21 04 04.68 De= +46 31 13.9 position measured from reference stars UCAC-4 catalogue.

2017 07 13.178

Mag.= B= 8.47, V= 8.77, Ic= 8.84, position end figures 04s.69, 13".6 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/PNV_J21040470+4631129.jpg.