COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2257

                                     Konkoly Observatory
                                     Budapest
                                     1983 January 3

                                     HU ISSN 0374-0676





            1982 UBVR PHOTOMETRY OF HD 108102


  We have completed a light curve for HD 108102 (SAO 82295, BD +26deg 2347)
that shows it photometric variability. The data was obtained between March
17, 1982 and June 10, 1982 at the University of New Mexico's Capilla Peak
Observatory. Our photon-counting system employs a cooled EMR 641A phototube
and a Kitt Peak UBVR filter set. The photon counts are fed to a microcomputer,
which integrates the data online to insure statistical errors for each point
of about +/- 0.01 magnitude or less (Elston and Zeilik, 1982).
  We used SAO 82325 (G5) as our comparison star. We compared the magnitude
of this star at V band with that of SAO 82631 (our comparison star for UX Com)
at very similar air masses for five different nights and found the total 
variation to be less than +/- 0.01 magnitude, consistent with our statistical error,
so SAO 82325 appears to have constant light output.
  Our results are summarized in Figures 1-4 in the instrumental UBVR magnitude 
system (comparison minus source). Phases were calculated using the 
spectroscopic period for this noneclipsing binary system, 0.9616 day (Barry, 1979),
and an arbitrary epoch of 2440000.0, The nights of observation and phases
covered are listed in Table I.

  Variations of the light curve of about 0.04 magnitude (except for the R-
filter data where more scatter is present) follow the same general pattern in
all four figures. The star definitely exhibits optical variability, but the


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



              TABLE I - 1982 Phase Log HD 108102

    Date (UT)   Phase       Date (UT)    Phase

    3/17        0.56-0.78    5/21        0.09-0.16
    4/3         0.19-0.28    5/31        0.46-0.59
    4/19        0.94-0.99    6/10        0.84-0.95




regions of phase overlap (0.56-0.59 and 0.94-0.95) have such large discontinuities 
in magnitude that we are sure that the photometric period and the spectroscopic 
period are not the same. Analysis of the data using a minimum-line-
length routine while varying the period indicates that other periods near one
day (notably 0.82 and 1.3 day) may fit the data much better, but further 
analysis and new observations with smaller gaps will be required to determine the
actual photometric period.




      M. ZEILIK, D. BATUSKI, S. BURKE, R. ELSTON and P. SMITH

               Capilla Peak Observatory
            Department of Physics and Astronomy
              The University of New Mexico
                Albuquerque, N.M. 87131
                       U.S.A.



References:
Barry, D.C., 1979, Ap.J., 230, p. L87. [BIBCODE 1979ApJ...230L..87B ]
Elston, R. and Zeilik, M., 1982 Pub. Astron. Soc. Pacific, Vol. 94, p. 729. [BIBCODE 1982PASP...94..729E ]