COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2818

                                         Konkoly Observatory
                                         Budapest
                                         14 November 1985

                                         HU ISSN 0374 - 0676



          PHOTOELECTRIC LIGHT CURVE AND TIMES OF

                   MINIMA OF V 1010 Oph


 The star V 1010 Oph (BV 544, HD 151676) is an eclipsing binary of Beta
Lyrae type. The variability of this star was discovered by Strohmeier, Knigge
and Ott (1964). Spectroscopic investigations revealed that it could be 
classified as a single lined A3 star (Popper, 1966).
 V 1010 Oph was observed photoelectrically by Leung (1974). He found that
the eclipse was complete and the primary minimum was a transit. He also found
that the primary star in the system was larger, hotter and had a spectral
type of A3, while the spectral type of the secondary component is around G8.
  Extensive photoelectronic observations for star V 1010 Oph were carried out
in two colours (B and V) in the second half of July 1985, in order to determine
any variations in period or shape of the light curve of this star.
  Photoelectric observations of this star were obtained using the 74 inch
reflector of Kottamia observatory, Egypt. The photometer used was a single
beam photoelectric photometer attached to the Cassegrain focus (f/18).
Standard B and V filters with EMI 9558 B photomultiplier type with S-20
photocathode cooled by a propeller fan were used throughout. The variable star
V 1010 Oph was observed more or less continuously through B and V filters
with only occasional measurements of the comparison star (HD 151527, sp. type
A0). During the interval of observations the nights were of good photometric
quality.
  From the individual observations, six moments of minima were obtained in
each colour. Epochs of minimum light were determined by the method of bisecting
chords. The derived epochs are listed in Table I.
O - C residuals were computed from the following ephemeris given by Leung (1974)

   J.D.Hel.Min.I. = 2438937.7690 + 0.6614272d E

This ephemeris was also used for the reductions of the observations to give a


                               [FIGURE 1]
                               [FIGURE 2]





                     Table I

              Times of minima of V 1010 Oph


J.D.observed   filter    Min.   E         O-C

2446268.3681   V         I      11083     +0.0014
2446268.3680   B                          +0.0013

2446269.3599   V         II     11084.5   +0.0011
2446269.3597   B                          +0.0009

2446270.3523   V         I      11086     +0.0014
2446270.3524   B                          +0.0015

2446272.3361   V         I      11089     +0.0009
2446272.3362   B                          +0.0010

2446273.3289   V         II     11090.5   +0.0015
2446273.3287   B                          +0.0013

2446274.3195   V         I      11092     +0.0013
2446274.3207   B                          +0.0012



complete light curve for B and V measurements. These light curves are shown in
Figures 1 and 2, where Delta m is the magnitude difference between the variable
and the comparison star.
  From these complete light curves we can conclude that no appreciable 
variations occur in the shape of the light curves of the system as compared with
the previously obtained light curves.





                      M. A. HAMDY, H. A. MAHDY, M. A. SOLIMAN
                      Helwan Observatory, Egypt



References:


Leung, K.C., 1974, Ap.J. 79, No.8, 852. [BIBCODE 1974AJ.....79..852L ]
Popper, D.M., 1966, I.B.V.S. No.154. [Error] [BIBCODE 1966AJ.....71..176R ]
Strohmeier, W., Knigge, R., Ott, H., 1964, I.B.V.S. No. 74.