COMMISSION 27 OF THE I. A. U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                             Number 3512

                                                       Konkoly Observatory
                                                       Budapest
                                                       31 August 1990

                                                       HU ISSN 0374 - 0676


       V759 CENTAURI: NEW TIMES OF MINIMA AND REVISED PERIOD

   The binary system V759 Cen (HD 123732) was discovered by Bond (1970)
on objective prism plates and confirmed by y-Strömgren photometric 
observations. Sistero and Castore de Sistero (1976) published the period P =
0.3939513d determined from UBV photoelectric times of minima. The light
curves of V759 Cen show very shallow ( DeltaV = 0.2 mag) and almost equal 
minima, most of the light variation seems to be ellipsoidal. Because of these
difficulties minima were misidentified when we reduced Bond's observations
and primary and secondary minima were interchanged, this was realized when
further observations were made. Here we present the results of UBV monitoring 
for minima of V759 Cen. The new minima are included in Table I: four
from Bosque Alegre Station of Cordoba Observatory (JD 2442918 to 2444724)
observed with the 1.54 m reflecting telescope and four (JD 2444808 to
2445079) from the 0.76 m reflector at El Leoncito of Felix  Aguilar 
Observatory, San Juan, Argentina.
   From all minima (old published values are also listed in Table I) now
extending over 11000 cycles we determined the following least squares linear
ephemeris:

          P.M. = JDhel 2443089.2898 + 0.39399903d x E
                           +/-.0012 +/-.00000030

    The O-C residuals from the above ephemeris in Table I are comparable to
the estimated mean errors (~0.0035d) derived from the averages in the three
wavelength determinations (compare for instance individual values as given
by Sistero and Castore de Sistero, 1976). There are two minima exceeding
twice the mean error, however determined from few individual observations
on eclipses whose circumstances are not neatly defined.




                  TABLE I


Min   Lambda       JD hel        Cycle        (O-C)
                  2440000 +

II      y          649.8352     -6191.5      -0.0096
I       y          650.0381     -6191.0      -0.0037
I      UBV        2122.8210     -2453.0      +0.0108
II     UBV        2195.5031     -2268.5      +0.0001
I      UBV        2195.7033     -2268.0      +0.0033
I      UBV        2196.4909     -2266.0      +0.0029
II     UBV        2196.6865     -2265.5      +0.0015
II     UBV        2221.5128     -2202.5      -0.0059
I      UBV        2918.6848     - 433.0      -0.0034
I      UBV        2920.6549     - 428.0      -0.0033
I      UBV        4416.6735     +3369.0      +0.0010
II     UBV        4724.5822     +4150.5      -0.0006
II     UBV        4808.5078     +4363.5      +0.0032
II     UBV        5050.8099     +4978.5      -0.0041
I      UBV        5076.6194     +5044.0      -0.0015
I      UBV        5079.7701     +5052.0      -0.0028



               R.F. SISTERO, B.A. CANDELLERO, S. MARTON and A. GRIECO

                           Observatorio Astronomico
                                and F.A.M.F.
                                Laprida 854
                            5000 Cordoba, Argentina



References:

Bond, H.E.: 1970 P.A.S.P. 82, 1065. [BIBCODE 1970PASP...82.1065B ]
Sistero, R.F. and Castore de Sistero, M.E.: 1976, IBVS, No. 1132.