COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1720

                                 Konkoly Observatory
                                 Budapest
                                 1979 December 21


         OBJECT STEPANYAN 153519 POSSIBLY OF U GEMINORUM TYPE


The object at 15h35.7m +19d01' (1950) was detected by J.A. Stepanyan
(I.B.V.S. No. 1630) as being faint (~18m) on the POSS prints of April 1950 and
bright (~14m) on Byurakan objective prism plates of the spring of 1979.

The inspection of roughly one thousand Sonneberg sky patrol plates showed that
the brightening of the star was not due to one eruption of unknown date but
that maxima of the star are not very seldom. Their brightness reaches 13.2m
pg (comparison to Mt. Wilson SA 84), their duration several weeks. In all
years, for which good series of plates are available, eruptions as well as
phases of invisibility (>14m) can be noticed.

At my request Drs. P. Notni and G.A. Richter kindly took three grating
spectrograms of 140 A/mm with the image tube device at the 2 m telescope of
Tautenburg Observatory under difficult observing conditions. These plates
confirm the findings of Stepanyan (l.c.): The spectrum is characterized by
broad (~=50 A) emission lines (consisting of several components each?) of
H_alpha, beta, gamma, HeI 5875 and HeII 4686, typical of the U Gem stars and
superposed on a fairly strong continuum. According to a crude estimate of the
observers at the slit the object's visual brightness was then (1979 Oct. 13.8
and 14.7 UT) ~=15.5, about halfway between maximum and minimum level.

Some more details of the photometric behaviour will be given in Mitt. uber
Veranderlichen Sterne Sonneberg.


W. WENZEL
Sternwarte, Sonneberg
Zentralinstitut fur Astrophysik
Akademie der Wissenschaften der DDR