COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2185

                                  Konkoly Observatory
                                  Budapest
                                  1982 August 9

                                  HU ISSN 0374-0676



    TIMES OF MINIMA FOR SOUTHERN HEMISPHERE ECLIPSING BINARIES


      A photoelectric survey in the uvby beta filter system has been
undertaken at Cerro Tololo Inter-American Observatory on approximately 315
southern hemisphere eclipsing binary stars. The major purpose of this study
was to determine accurate colors in and out of the minima, accurate depths
of minima, and better ephemerides where necessary. One result of these 
observations has been the determination of times of minima for many of the
program stars. These are presented here.
      For each star the average time of minimum in all filters is
listed in Table I. Since coverage was generally not symmetrical for
ingress and egress, the tracing paper technique has been used throughout.

                  Table I

            Times of Minima-Determinations
Star       J.D. Hel.(2444000.0+)   Minimum
------------------------------------------
AD Phe         250.5863               I
AA Cet         238.5531               I
RU Eri         249.6161               I
BZ Eri         233.5800               I
RV Pic         233.8021               I
TU CMa         236.7892              II
FF CMa         236.6869              II
MQ Pup         234.5649               I
VZ Hya         236.6532               I
RS Cha         236.7639               I
RZ Pyx         245.7195              II
CW Vel         248.7584               I
RV Crt         247.8151               I
RW CrA         462.5323               I
V681 CrA       460.6822               I
U Sct          468.6658               I
V505 Sgr       461.5901               I
V Gru          463.8040               I
CZ Aqr         468.8852               I




      Many stars were also observed only during ingress and minimum or
during the minimum and egress. Although accurate times of minima could
not be determined, estimates of the center of the minimum have been made
for those stars whose ephemerides as listed by Wood et al. (1980) seem
significantly off, These are presented in Table II.



                    Table II
           Times of Minima-Estimates
Star       J.D. Hel.(2444000.0+)   Minimum
-------------------------------------------
TY Men           253.709              I
CW CMa           235.679              I
UZ Pup           253.623              I
TT Pyx           234.800              I
GL Car           283.497              I
SS Cen           382.650              I
ES Lib           458.753             II
V535 Ara         458.533             II
RS Sct           458.753             II
BL Tel           470.668             II



      In addition the star V Gru has been found to have a period
significantly different from that listed by Wood et al, (1980). From
observations made on several nights during August 1980 an approximate
period of 0.4833 days has been determined. Combined with the new time
of minimum listed above the new provisional light elements are
              JD 2444463.8040 + 0.4833d
The light curve is a W-type with unequal minima.
      Other results form this survey are being published elsewhere.

                       GEORGE W. WOLF *
                       JANET T. KERN *
                       TONY L. HAYES
                       CARL R. CHAFFIN
                       Southwest Missouri State University
                       Department of Physics
                       Springfield, Missouri, USA.


Reference:

Wood, F.B., Oliver, J.F., Florkowski, D.R., and Koch, R.H., 1980, A Finding,
  List for Observers of Interacting Binary Stars


* Visiting Astronomer, Cerro Tololo Inter-American Observatory, supported by
the National Science Foundation under contract No. AST 78-27879.