COMMISSION 27 OF THE I. A. U.
                  INFORMATION BULLETIN ON VARIABLE STARS
                              Number 3522

                                                        Konkoly Observatory
                                                        Budapest
                                                        1 October 1990

                                                        HU ISSN 0374 - 0676


                 QUIESCENT LIGHT VARIATION OF UV Per


   UV Per was confirmed as an SU UMa type dwarf nova with the superhump period
of 95.5 minutes (Udalski and Mattei, 1989). But neither radial velocity study
nor search for photometric periodicity in quiescence have been undertaken to
determine the orbital period.
   Our observations were done with Thomson CCD (576x384 pixels, on chip
summation of 2x2 pixels) attached to the Cassegrain focus of the 60cm
reflector at the Ouda Station on August 5, 1990. The Johnson V filter was
employed and the exposure time was 480 seconds.
   The frames were processed with the point spread function (PSF) photometry
package developed by the author. PSF profiles were empirically determined
from other nine brighter stars in the same frame. We converted our
instrumental (differential) magnitudes into the V mags., using the Guide Star
Catalog (GSC) for 12 stars between V=10.8 and V=13.4 in the same frame. The
resulting zero point is 11.6 +- 0.1 in magnitude.
   Figure 2 illustrates the processed CCD image containing the variable (V) and
the check star (C). When compared with the position in POSS print (Bruch,
Fischer and Wilmsen, 1987), UV Per shifts roughly 3 arcsec towards east. This
large proper motion deserves further astrometric observations.

                               [FIGURE 1]


   The mean brightness of UV Per in this run was V=17.0 +- 0.1, in good
agreement with that given by Szkody (1985). Table 1 and Figure 1 gives our
result for UV Per and the check star. The expected r.m.s. error of a single
observation of UV Per is about 0.11 mag., due to the high sky count in the
nearly full moon. One can see roughly sinusoidal variation with an amplitude
of 0.6 magnitude and two rather distinct minima separated by about 1.5 hours.
The maximum entropy method gives the most probable period of 89.6 minutes and
expected one sigma error of 0.4 minutes. Superhump periods in SU UMa systems
are generally a few percent longer than the orbital period (Stolz and Schoembs,
1984), thus our light curve likely reflects the orbital period.


          Table I.

UT(Geo)       UV Per    Check
Aug.,1990     Delta m   Delta m

5.6551        5.22      5.01
5.6612        5.65      5.14
5.6673        5.53      4.97
5.6734        5.63      5.25
5.6796        5.52      5.25
5.6862        5.37      5.26
5.6924        5.32      5.27
5.6986        5.51      5.10
5.7049        5.15      5.25
5.7110        5.14      5.00
5.7171        5.45      5.10
5.7238        5.29      5.27
5.7303        5.49      5.09
5.7364        5.53      5.30
5.7490        5.47      5.17
5.7555        5.23      5.20
5.7616        5.31      5.38
5.7677        5.44      5.27
5.7738        5.30      5.19


                          [FIGURE 2]



                            TAICHI KATO

                            Dept. of Astronomy, Faculty of Science,
                            Kyoto University,
                            Sakyo-ku, Kyoto 606, Japan



References:

Bruch, A., Fischer, F. J., and Wilmsen, U., 1987, Astron. Astrophys. Suppl.
     Ser. 70, 481. [BIBCODE 1987A&AS...70..481B ]
Stolz, B., and Schoembs, R., 1984, Astron. Astrophys. 132, 187. [BIBCODE 1984A&A...132..187S ]
Szkody, P., 1985, Astron. J. 90, 1837. [BIBCODE 1985AJ.....90.1837S ]
Udalski, A., and Mattei, J. A., 1989, IAU Circ. No. 4885. [BIBCODE 1989IAUC.4885....2U ]