COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 2006

                                 Konkoly Observatory
                                 Budapest
                                 1981 August 25

                                 HU ISSN 0374-0676




               UBVR PHOTOMETRY OF UV Psc




   As part of an on-going program of UBVR photometry of RS CVn binaries, we
have observed the short-period system UV Psc (+6d189) several times in 1979 and
1980. The observations were made with the University of New Mexico's 61-cm
Capilla Peak Observatory telescope. A photon-counting system using a cooled
EMR 641A phototube was employed along with KPNO filters; the R filter was not
available until fall 1980. The star +6d185 (SAO 108761) was used as the 
comparison star.
   The results of these observations are shown in Figure 1-4. The statistical
error of any single point is on the order of +-0.02 magnitude. The phases were
calculated using HJD = 2443463.3493 + 0.861046 E (Oliver, 1974; IBVS 1415).
   Very few observations of UV Psc have been published to date. Popper (1969)
noted that UV Psc had H and K emission from both components. He classified the
system as being G2. Oliver (1974) observed UV Psc photometrically and found
that the light curve of UV Psc did not have any large asymmetries. Also, Oliver
presented a light curve made by Carr in 1968. Oliver stated that his light curve
was very similar to that of Carr's, with the exception of a depression in Carr's
curve around 0.75 phase. The similarities between the light curves of Oliver and
Carr indicated that UV Psc had a rather consistent light curve.

   Our light curves appear quite different from those of Oliver and Carr.
First, they do not show any evidence for an asymmetrical distortion wave in the
light curve of UV Psc. Second, our observations do show that UV Psc is a very
active system that undergoes radical changes in its light curve. At 0.0 phase,
there is evidence for a large change in the depth of the primary minimum between
the observations made on 12/16/1979 and those made on 10/8/1980. The difference
in depth is greater at longer wavelengths. Also, there is a very large depression 
of the light curve just after the primary minimum at 0.1 phase on 12/16/
1979. This depression is deeper at longer wavelengths. On 11/2/1980, the light


                          [FIGURE 1]
                          [FIGURE 2]
                          [FIGURE 3]
                          [FIGURE 4]


curve was depressed, only in the U, after the secondary minimum. Like the 
primary minimum, the secondary minimum increases in depth with longer wavelength.
   We plan to continue our observations of UV Psc to fill the gaps in our
light curves and to look for more unusual short-term features in them.


           M. ZEILIK, R. ELSTON, G. HENSON, P. SMITH
             Department of Physics ad Astronomy
                The University of New Mexico
                    Albuquerque, NM 87131
                           U.S.A.





References:
Oliver, J. P., 1974, Ph.D. Thesis, University of California, Los Angeles,
   California, U.S.A. [BIBCODE 1974PhDT.........1O ]
Popper, D. M., 1969, B.A.A.S., 1, 257. [BIBCODE 1969BAAS....1..257P ]