Electronic Telegram No. 2840 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network VARIABLE STAR IN PERSEUS: TCP J04283707+3157578 Timur Krychko and Boris Satovski report their discovery of a previously unknown variable star (mag 16.9) on unfiltered CCD images (limiting red mag 20.5) obtained on Sept. 22.012 UT using a 0.30-m f/8 reflector at the Astrotel Observatory, Zelenchukskaya Station, in Russia. The variable is located at R.A. = 4h28m37s.07, Decl. = +31d57'57".8 (equinox 2000.0 presumed). Nothing is visible at this position on Digitized Sky Survey (DSS) images taken on 1989 Nov. 14 and 1996 Nov. 4, and nothing is visible in 2MASS images obtained on 1999 Nov. 26. However, the object appears visible at mag 17 on Palomar Sky Survey images taken on 1955 Oct. 22 and 1992 Oct. 1. Krychko has posted an image marking the variable at the following website URL: http://www.astroalert.su/files/tcp_04283707_3157578_2011-09-22.jpg. This variable was designated TCP J04283707+3157578 when it was posted on the Central Bureau's TOCP webpage. Joseph Brimacombe, Cairns, Australia, reports unfiltered CCD mag 19.0 and position end figures 37s.0, 58".1 from an image taken on Sept. 26.426. L. Tomasella, S. Valenti, S. Benetti, and P. Ochner, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica; and A. Pastorello, Dipartimento di Astronomia, Universita di Padova, report that a spectrogram of TCP J04283707+3157578 (range 360-810 nm; resolution 2.2 nm) was obtained on Sept. 26.10 UT with the Ekar-Copernico 1.82-m telescope (+ AFOSC). The spectrum shows a strong H_alpha emission. Compared to H_alpha, H_beta is weak but also perceptible: the possible absorption dips surrounding H_beta could be the residual effect of the accretion disk following outburst, as is typically evident in dwarf novae (Szkody et al. 1990, Ap.J. Suppl. 73, 441). There is a trace of He I emission at 587.6 nm, while all other expected lines seems to have drowned in the noise. So the classification of this object as a cataclysmic variable is plausible. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 September 29 (CBET 2840) Daniel W. E. Green