CSS160603:162117+441254 shows deep eclipses during the ongoing outburst
ATel #9132; M. Zejda (Masaryk University), O. Pejcha (Princeton)
on 9 Jun 2016; 13:45 UT
Credential Certification: Ondrej Pejcha (pejcha@astronomy.ohio-state.edu)
Subjects: Optical, Binary, Cataclysmic Variable
We report time-resolved R-band photometric observations of CSS160603:162117+441254 = 2MASS J16211735+4412541 (ATel #9112, #9113, #9122) during four nights (UT 2016 June 5.33-5.57, 6.33-6.57, 7.33-7.57, and 8.33-8.57) using the Moravian Instruments G2-4000 CCD camera attached to the 60cm Newtonian telescope at the Masaryk University Observatory in Brno, Czech Republic. The exposure times were 60-70 seconds.
The phased light curve shows deep primary eclipses, shallower secondary eclipses and an out-of-eclipse variability, which we cannot sufficiently characterize with the available data. This is markedly different from the pre-outburst light curve exhibiting smooth double-hump light curve resembling ellipsoidal variability in a binary star (Lohr et al. 2013, A&A 549, A86).
As the outburst fades, the depth of primary minima decreases, while the depth of secondary minima increases. We measured approximate depths of 1.05, 0.95, 0.90, and 0.85 mag for the primary minima, and 0.10, 0.15, 0.25, and 0.30 mag for the secondary minima on the four consecutive nights of our observations. The object is currently fading with a rate of 0.2-0.3 mag/day. The current outburst is thus consistent with a brightening of a compact object in a cataclysmic binary star.
Further observations of this intriguing object are encouraged.
