[ Previous | Next ]
ATEL # 978; E. Gogus (Sabanci University, Istanbul), T. Guver, M.T. Ozkan (Istanbul University, Istanbul)
on 18 Jan 2007; 11:37 UT
Password Certification: Ersin Gogus (firstname.lastname@example.org)
Subjects: Optical, Cataclysmic Variables, Variables
Monitoring observations of U Gem with ROTSE-IIId telescope located at TUBITAK National Observatory, Bakirlitepe-Antalya, Turkey reveal that the dwarf nova system is in outburst. U Gem undergoes outbursts once in about 120 days. The V magnitude of the system rises from the quiescent level of about 14 to about 9. Our observations of U Gem started on UT 2007 January 16.83 and the calibrated R-magnitude (using USNO A2.0) of the source was found to be R_cal=9.45+/-0.002. We observed the source between UT 2007 January 17.75 and 17.88, and found a moderate optical brightening from R_cal=9.25+/-0.002 to R_cal=9.16+/-0.002. Rather gradual brightness increase throughout the ROTSE-IIId observations may indicate that the source was near the optical peak of outburst. The optical brightness of the source is expected to remain around the current level for about 3-4 days, then decline back to the quiescent level in about 5-6 days.