Optical brightening of XRB SAX J2103.5+4545

Astronomer's Telegram #6019

T. S. Konstantinova, A. A. Mokrushina (St. Petesburg Univ., Russia)
on 28 Mar 2014; 13:07 UT

We report on the renewed optical activity of the high-mass X-ray binary system SAX J2103.5+4545. The source was monitored with the 0.4-m LX-200 (St.Petersburg, Russia) telescope. In the night of 2014-03-27 the brightness of the optical counterpart reached R= 13.20+/-0.02, as compared to R= 13.60+/-0.02 in the night 2014-01-29. Last fourteen months, since December 2012, the system was in optical quiescent state. The previous optical activity observed from March 2013 (see ATel#4068) was followed by onset of X-ray activity of the source (ATel#4168) and also the IR brightening of the system and H-alpha line emission (ATel#4187). New spectral observations of the system are desirable for monitoring a recent disc formation around the Be star.