COMMISSION 27 OF THE I. A. U.
           INFORMATION BULLETIN ON VARIABLE STARS
                        Number 3689    

                                               Konkoly Observatory
                                               Budapest
                                               10 December 1991

                                               HU ISSN 0374 - 0676


    V 1251 CYGNI - UNSUCCESSFUL SEARCH FOR ADDITIONAL ERUPTIONS


Moriyama and Schmeer (1991) announced a new eruption of V 1251 Cyg in October
1991, and Kato (1991) afterwards reported on the development of superhumps.

On 536 suitable Sonneberg Sky Patrol plates taken in the years 1941 to 1990
mainly by H. Huth and B. Fuhrmann, no further eruption could be detected
with the exception of the October 1963 outburst of Weber (1966), which was
confirmed by two of my observations. Only plates are counted which at least
reach magnitude 13.3m (pg) in Weber's system (comparison star c).

We conclude that this is one of the rare SU Ursae Majoris stars with time
intervals of several years between successive superoutbursts (= outbursts with
superhumps). "Normal" maxima, which usually are of remarkably smaller
amplitude, could be easily hidden below the threshold of our plates. However,
the object might also behave like WZ Sge, where normal eruptions are obviously
missing at all.

On the POSS charts a small triangle of 18.5m stars, the southwestern of them is
bluish, lies at the position. If one of these objects is the cataclysmic
variable, then the observed amplitude of about 6 mag of the supermaxima as
well as the superhump period of 0.076d leads to a cycle length of roughly
three years (see the relationships given by Brauer and Richter (1989).
Therefore, both thoroughly watching the locality by visual or CCD patrol
techniques to possibly reveal normal eruptions and the search for the genuine
low state object would be promising tasks.


                         W. WENZEL
                         Sternwarte Sonneberg
                         Deutschland

References:

Kato, T.: 1991, IAU Circ. No. 5379 [BIBCODE 1991IAUC.5379....4K ]
Moriyama, M., Schmeer, P.: 1991, IAU Circ. No. 5377 
Richter, G.A., Brauer, H.-J.: 1989, Astron. Nachr. 310, 413 [BIBCODE 1989AN....310..413R ]
Weber, R.: 1966, I.B.V.S. No. 123