COMMISSION 27 OF THE I. A. U.
            INFORMATION BULLETIN ON VARIABLE STARS
                         Number 3086


                                           Konkoly Observatory
                                           Budapest
                                           16 September 1987

                                           HU ISSN 0374-0676


           LONG-TERM LIGHT-CURVE OF THE CATACLYSMIC
                   BINARY V 425 CASSIOPEIAE


   The variability of V 425 Cas = S 9712 was detected by Hoffmeister (1966,
1967). The discoverer and later on Platejs and Rozenbush (1980) considered
the star as a probable R Coronae Borealis variable, because the minima were
rare and of rather long duration. No further photometric observations are
known to me.
   The true nature of the object has been discovered spectroscopically by
Shafter and Ulrich (1982): It is a cataclysmic binary with an orbital period
of 0.14964 days. Therefore it seemed desirable to study the long-term 
photometric behaviour in more detail.
   An investigation on 297 plates taken with the Sonneberg 400 and 170 mm
astrographs yields the following picture of the light-curve. The star was
bright (mpg = 14.6, standard deviation = +0.3 mag, n = 248) without exception
from 1935 to 1951 and from 1956 to 1964 (no plates available 1952 to 1955).
Slow, systematic fluctuations around the quoted mean brightness of this upper
stage with an amplitude of perhaps 0.6 mag are indicated but may originate
from instrumental effects. However, from 1965 to 1977 and probably also from
1983 to 1985 the star was very restless (no observations 1978 to 1982 and
since 1986) - see figure. Several deep minima of a duration of some weeks at
least, or even years, and a depth down to >= 18.5 mag occurred, interrupted by
intervals of high state.
   So the star amazingly resembles the "nova-like" cataclysmic binaries TT
Ari, MV Lyr or KR Aur, which are characterized by ceasing mass transfer in low
state. We suppose that there are more such objects among the purely 
photometrically classified so-called R Coronae Borealis stars.
   Meaning of symbols in the figure is: filled circles - Sonneberg (small-
single observations, large-night averages), crosses - Riga (approximate),
arrows - upper limits. Magnitude system of Mt. Wilson Selected Area 42.


                            [FIGURE 1]



                         W. WENZEL

                      Sternwarte Sonneberg
                      Zentralinstitut fur Astrophysik
                      der Akademie der Wissenachaften
                      der DDR



References:

Hoffmeister, C., 1966, Mitt. Veranderl. Sterne 3, p.178
Hoffmeister, C., 1967, Astron. Nachr. 289, p.211 [BIBCODE 1967AN....289..205H  ]
Platejs, I., Rozenbush, A., 1980, Issled. solntsa krasnykh zvezd, Riga
                no. 11, p.40 [BIBCODE 1980ISKZ...11...27P ]
Shafter, A.W., Ulrich, R.K., 1982, Bull. American Astron. Soc. 14, p. 880 [BIBCODE 1982BAAS...14..880S ]