Central Bureau for Astronomical Telegrams

CBAT "Transient Object Followup Reports"

TCP J17521907+5001155

TCP J17521907+5001155   2012 08 17.83  *  17 52 19.07 +50 01 15.5  16.6 U             Her       7 0

2012 08 17.83

Discovered by H. Mikuz, Crni Vrh Observatory (mag. 16.6) on four unfiltered CCD images (bandpass roughly equivalent to the R band) taken on 2012 Aug. 17.82-17.84 UT with the 60-cm f/3.3 Cichocki reflector in the course of the Comet and Asteroid Search Program (PIKA) Image http://www.observatorij.org/vstars/TCP20120817/b1745+510021.jpg (signed with red circle). Nothing is visible at this location on archival PIKA images, obtained on 7 nights between 2008 May. 9 and 2011 Oct. 9 with limiting magnitudes about 19.0-19.5. Also, nothing is visible at this position on several Digitized Sky Survey red and blue images from the Palomar Sky Survey.

2012 08 19.80

Photometry by H. Mikuz: R=17.0 +/- 0.1

2012 08 16.580

D. Denisenko, V. Lipunov (SAI MSU), V. Yurkov, E. Sinyakov (Blagoveschensk Educational State University) report on behalf of a larger MASTER collaboration: TCP J17521907+5001155 was found on two unfiltered survey images (60-sec exposures) taken by MASTER-Amur robotic telescope (0.40-m f/2.5 reflector + 16 Mpix CCD) on 2012 Aug. 16 at 13:54:42 UT and 14:00:09 UT (30 hours before the discovery images posted at TOCP). Unfiltered magnitude on Aug. 16.580 UT was 15.6+/-0.1. Nothing is visible at this position on MASTER-Amur images of 2012 July 31.64 (limiting magnitude 17.7). We also note that this object is identical to the blue star in SDSS catalogue with the following position end figures: 19.07s, 15.7" and magnitudes: u=22.21, g=22.16, r=22.31, i=22.21, z=22.26. Based on the blue color and amplitude of variability (about 6 mag) we conclude that this object is a cataclysmic variable (dwarf nova) in outburst. Comparison of Aug. 16 and July 31 MASTER-Amur images together with SDSS color image is posted at http://master.sai.msu.ru/static/OT/TCPJ17521907+5001155-MASTER.jpg

2012 08 23.12

Two hours of time resolved photometry, with the source low on the NE horizon, show superhumps, revealing this is a new SU UMa dwarf nova. The superhump period is close to two hours or so. Observations performed by G. Masi and F. Nocentini remotely using the 14" unit part of the Virtual Telescope robotic facility, in Italy.