Central Bureau for Astronomical Telegrams

CBAT "Transient Object Followup Reports"

TCP J15244460-6059200

TCP J15244460-6059200   2022 06 25.487 *  15 24 44.60 -60 59 20.0  10.7 U             Cir       1 0

2022 06 25.487

Discovered by Andrew Pearce, Nedlands, Western Australia, who found this star on three images (limit mag.= 12.5) taken with Canon 800D digital camera + 85-mm f/1.2 lens, writes nothing is visible at the discovery position on three frames taken on 2022 June 22.521 UT or June 24.478 UT with the same instrument. Star was visually confirmed on June 25.566 UT at magnitude 10.7. Position is approximate.

2022 06 25.635

Position end figures 47s.60, 47".3 measured with 0.50m f/6.8 reflector + CCD at Siding Spring, NSW, Australia. J2000, Gaia DR2 positions. Position coincides with a star visible on DSS2 red image. The transient was also detected by the ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017PASP..129j4502K) at a magnitude of approximately 14.0 on June 19.12 UT with most recent observation on June 25.20 UT at magnitude 10.9. No previous variability noted. Further visual magnitude estimates as follows: June 25.598 UT 11.1, June 25.632 UT 11.2. Andrew Pearce, Nedlands, Western Australia

2022 06 25.637

Photometry using T30 0.5m f/6.8 reflector + CCD at Siding Spring as follows: June 25.637 UT V = 11.39, June 25.638 UT B = 12.07. Andrew Pearce, Nedlands, Western Australia.

2022 06 25.8125

Follow-up observations remotely using T30 (iTelescope.Net): 0.50-m f/6.8 reflector of Siding Spring Observatory (Australia): 2022 Jun. 25.6794 V = 11.25 +/- 0.01; 2022 Jun. 25.6822 B = 12.03 +/- 0.03; 2022 Jun. 25.6849 Rc = 10.37 +/- 0.01. The object's position is almost the same as the source 5875610751015084544 in the Gaia DR3 catalogue. The ASAS-SN light curve: https://asas-sn.osu.edu/sky-patrol/coordinate/5adadbd1-c25e-4aab-9060-fa7ce91bbe81 (indicates that the object did not change brightness significantly before 2022-06-25.200 when it had g mag = 10.9). Filipp Romanov (Russia).

2022 06 26.451

Visual magnitude estimate on June 26.451 UT - 12.2. ATel # 15473 recently issued which confirms the spectrum resembles that of a very fast classical nova after optical peak. The low amplitude of the transient raises questions about its nature and the possible progenitor match. Andrew Pearce, Nedlands, Western Australia.