Special Notice #399: GK Per in outburst

March 12, 2015: The old nova GK Per (N Per 1901), which has dwarf nova outbursts, is going into outburst, according to observations submitted to the AAVSO International Database:

2015 Mar. 06.06667 UT, 12.9 (SLH, L. Shotter, Uniontown, PA);
06.81806, 13.0 (OJR, J. Ripero, Madrid, Spain);
06.83060, 13.3 (BVE, E. van Ballegoij, Heesch, Netherlands);
06.83750, 13.1 (MUY, E. Muyllaert, Oostende, Belgium);
06.84167, 12.8 (SPK, P. Schmeer, Bischmisheim, Germany);
07.02222, 12.5 (Shotter);
07.81250, 12.4 (Muyllaert);
07.82153, 12.0 (Ripero);
07.83125, 12.4 (Schmeer);
07.84900, 12.3 (PYG, G. Poyner, Birmingham, England);
07.87850, 12.3 (GGU, G. Gilein, Noordwijk, Netherlands);
08.02690, 12.226 CV +/-0.010 (UJHA, J. Ulowetz, Northbrook, IL, 171 obs 08.02690-.11524);
08.07363, 12.093 CV +/-0.008 (Ulowetz);
08.11524, 12.254 CV +/-0.010 (Ulowetz);
08.82292, 12.0 (WKL, K. Wenzel, Grossostheim, Germany);
08.85100, 12.1 (Poyner);
09.01667, 12.0 (Shotter);
09.02920, 12.1 (BRJ, J. Bortle, Stormville, NY);
09.78750, 12.2 (KWO, W. Kriebel, Schierling/Walkenstetten, Germany);
10.01880, 12.1 (Bortle);
10.02845, 12.051 CV +/-0.009 (Ulowetz, 154 obs 10.02845-.10884);
10.03060, 12.2 (KMA, M. Komorous, London, ONT, Canada);
10.06788, 11.960 CV +/-0.011 (Ulowetz);
10.10884, 12.191 CV +/-0.089 (Ulowetz);
10.78417, 12.152 V +/-0.004 (DUBF, F. Dubois, Zillebeke, Belgium, 143 obs 10.78417-.84714);
10.81736, 12.0 (Muyllaert);
10.81965, 11.870 V +/-0.003 (Dubois);
10.82361, 11.8 (Ripero);
10.83190, 12.0 (Gilein);
10.84714, 12.022 V +/-0.004 (Dubois);
11.02780, 12.1 (Komorous);
11.77778, 12.1 (Wenzel);
12.01320, 12.1 (Bortle);
12.02780, 12.2 (Komorous);

GK Per has dwarf nova outbursts about every 18-24 months, although the interval can vary quite a bit. It is difficult to predict how bright this outburst may be; the brightness and duration of recent GK Per outbursts has varied substantially.

Its last outburst was almost exactly two years ago, in March 2013, when it reached V=12.2 and was brighter than V=12.8 for only 17 days, according to the AAVSO International Database (AAVSO Special Notice #343). That outburst is the faintest and shortest on record since July 1978.

Its previous outburst was three years earlier, in March 2010, when it reached V=9.7 and was brighter than V=12.8 for at least 100 days (the exact number of days is unknown because GK Per returned to minimum during its seasonal gap), according to the AAVSO International Database. That outburst is the brightest on record since the nova outburst in 1901. The 2010 outburst brightness may be related to the long interval to the 2013 outburst, as well as to the interval between the 2008 and 2010 outbursts, which was six months shorter than usual. (The September 2008 outburst reached V=12.1 and was brighter than 12.8 for about 30 days.)

Please monitor GK Per and report your observations to the AAVSO, using the name GK PER.

Coordinates:  R.A. 03 31 12.01   Dec. +43 54 15.4 (2000.0)

Charts for GK Per may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp).

This AAVSO Special Notice was compiled by Elizabeth O. Waagen.

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