COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                  Number 1838

                                Konkoly Observatory
                                Budapest
                                1980 September 4

                                HU ISSN 0374-0676





      ROTHNEY ASTROPHYSICAL OBSERVATORY PUBLICATION
                 SERIES B, No. 5


         PHOTOELECTRIC OBSERVATIONS OF XY LEONIS



    XY Leonis (BD +18deg2307) is a W Ursae Majoris type star
with a variable period. Because of the shortage of published
data on XY Leonis, as pointed out by Mauder (1972), Binnendijk
(1970), Rucinski (1974) and Koch and Shanus (1978), we present
here UBV data, which we obtained as part of a senior undergraduate 
laboratory project in the Astrophysics program at the University 
of Calgary. Though incomplete, these data may be useful
for comparison to Shanus' 1978 observations (Koch and Shanus,
1978), obtained about the same time as ours. In particular, our
data substantiate those authors' decision to exclude from analysis 
Shanus'data of JD 2,443,573.
    XY Leonis was observed using the 41 cm telescope at Rothney 
Astrophysical Observatory (University of Calgary) employing
a dry-ice cooled EMI 6256 photometer at -1000 V (DC). Magnitudes
were measured in the U, B and V, then transformed to the Johnson
system. The comparison star chosen was BD +18d2309. Data was
acquired on six nights during the period February 26 to April 7
of 1978. The ephemeris used is that due to Gehlich et al.(1972):
    2,435,484.0222 +- 0.0016 + (0.28410282 +- 0.00000007).E (1).
Our light curves, presented in Figures 1 to 3, show a phase shift
of approximately +0.04p, resulting in an O-C of 0d012+-0.006 at JD
2,443,587.783 +- 0.003, which is not significantly different from
This represents an average over all six nights, assuming the period 
remained approximately constant.

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


that of Koch and Shanus (t978), and essentially confirms the
departure from the O-C curve of Gehlich et al., first suggested
by the data of Pohl and Kizilirmak (1977).
    The present results support the conclusion of Koch and
Shanus (1978) that XY Leonis is best considered a double, and
not a triple, system.
    The authors wish to thank Dr. E.F. Milone and R.M. Robb
for assistance during the course of this work.






          JOHN S. HEBRON and MARK R.A. SHEGELSKI
          Department of Physics, University of Calgary,
          Calgary, Alberta, Canada T2N 1N4







References:

Binnendijk, L. 1970, Vistas in Astronomy, Vol.12, ed.A.Beer
        (Oxford; Pergamon Press),p. 217 [BIBCODE 1970VA.....12..217B ]
Gehlich, U.K., Prolss,J. and Wehmeyer, R. 1972, Astron.Astroph.
        18, 477 [BIBCODE 1972A&A....18..477G ]
Koch, R.H. 1960, A.J. 65, 374 [BIBCODE 1960AJ.....65..374K ]
Koch, R.H. and Shanus, C.R. 1978, A.J. 83, 1452 [BIBCODE 1978AJ.....83.1452K ]
Mauder,H. 1972, Astron. Astroph. 17, 1 [BIBCODE 1972A&A....17....1M ]
Pohl, E. and Kizilirmak, A. 1977, I.B.V.S. No. 1358
Rucinski, S.M. 1974, Acta.Astr. 24, 119 [BIBCODE 1974AcA....24..119R ]