COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2073

                                 Konkoly Observatory
                                 Budapest
                                 1982 January 18

                                 HU ISSN 0374-0676





   HD 8152 - A NEW W URSAE MAJORIS TYPE ECLIPSING BINARY





  While making observations of the X-ray star HD 8357 for
detecting any RS CVn type light variations in the optical region,
it was found that the star HD 8152 used as a check star, showed
light variations. Subsequently HD 8152 was observed photoelectrically 
on thirteen nights during 1980-81. The observations were
made with the 48-inch telescope of the Japal-Rangapur Observatory,
through the standard U,B and V filters. An unrefrigerated EMI
6256 B photomultiplier was used, the output of which was fed
to a GR 1230A D.C. amplifier and a Honeywell-Brown strip chart
recorder. Stars HD 8523 and HD 8171 were used as comparison and
check stars respectively. All the observations were reduced to
outside the atmosphere by applying nightly extinction coefficients
for each filter determined from the observations of the comparison 
star. The differences Delta m (variable - comparison) were then
transformed to the Johnson and Morgan's standard UBV system
using the transformation relations obtained from the observations
of the UBV standard stars.
  The observed magnitude differences Delta m (check - comparison)
on different nights show for a single observation a standard
deviation of +- 0.02m in V, +- 0.01m in B, and +- 0.02m in U. This
indicates that the comparison and check stars remained constant
during the period of our observation within the above limits.
  The observations of all the 13 nights were analysed by the
method of Marraco and Muzzio (1980) for a period determination.
From this analysis the Ephemeris of the variable is found to
be HJD of Primary Minimum = 2444562.4691 + 0.47564d E.


                    [FIGURE 1]

   The light curve in yellow, computed with this Ephemeris is
shown in Figure 1. This shows the nearly equal depths of primary
and secondary minima and the continuous light variation outside
the eclipses, characteristic of the W Ursae Majoris type eclipsing 
binaries. The magnitudes and depths in the various colours
are found as:

------------------------------------------------
                           V       B       U
------------------------------------------------
Magnitude at Maximum      8.60m   9.10m   9.10m
Depth of Primary Minimum  0.364m  0.376m  0.392m
Depth of Secondary
Minimum                   0.330m  0.360m  0.359m
------------------------------------------------

  From the (B-V) colour of + 0.5m and (U-B) colour of + 0.0m at
maximum light, the combined spectral type of the system is
found to be F8V (Allen 1976). This is within the range of spectral 
types of other known W Ursae Majoris stars.
  Photometric and spectroscopic observations of the new variable
are in progress to obtain the elements.





              M.B.K. SARMA

              K.R. RADHAKRISHNAN

              Centre of Advanced Study in Astronomy
              Osmania University
              Nizamiah Observatory
              India




References:
Allen, C.W. 1976, Astrophysical Quantities, Ed. 3, Athlone Press. [BIBCODE 1976asqu.book.....A ]
Marraco, G.H. and Muzzio, J.C. 1980, P.A.S.P. 92, 700. [BIBCODE 1980PASP...92..700M ]