COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2186

                                       Konkoly Observatory
                                       Budapest
                                       1982 August 11

                                       HU ISSN 0374-0676


                     FIVE NEW VARIABLE STARS




  During the past two years, we have searched for photometric
variations in the light of 29 short-period stars in the Seventh
Catalogue of the Orbital Elements of Spectroscopic Binary Systems
(Batten et al. 1978). We observed through a V-filter with a 
computer-managed photon-counting photometer mounted on the 16-inch
Boller and Chivens reflector of the Oak Ridge Station, and each
spectroscopic binary was observed on from 8 to 50 nights relative
to a nearby comparison star. Times of observation were reduced
to phases using the catalogue value of the orbital period and an
arbitrary epoch, and the observed magnitudes were corrected for
differential extinction. Our level of detectability is estimated
to be about 0.02 mag peak to peak.
  We have found four stars whose light can be seen to vary
smoothly with the period of the velocity variation, and these
stars are listed in Table I.

                            Table I
Spectroscopic Binaries Showing Photometric Variations
No. in       HD      Sp.     Period  DeltaV       K_1/K_2         Phase
7th Cat.                     (days)  (mag.)      (km/sec)       Min^1.
 12          1826   A5      1.4323   0.025         53.4/-        0.3
804        193536   B2V     2.9847   0.05         115.0/141.0    0.4
832        198784   B2V     3.3035   0.09          63.8/-        0.95
844        200776   B1IVp   2.9258   0.20(ecl?)    62.5/-
896        209961   B2V     2.1727   0.08         121.7/-        0.25

^1 Phase of one of the light minima computed with the catalogue
period and arbitrary epoch June 1.0, 1980.

Their comparison stars are Listed in Table II, These new




          Table II
      Comparison Stars
Variable Comp. Star    B-V
   HD         HD
  1826       1439     -0.66
193536     192983     -0.48
198784     197226     -0.74
200776     200595     -0.05
209961   SAO51686     -0.68



variables show the double-peaked curve that is characteristic of 
ellipsoidal variables. The fifth variable (HD 200776) has shown
an abrupt drop in brightness by about 0.2-0.4 mag on five 
occasions. The phases of these drops do not seem consistent with a
simple eclipse model.
  Table III lists stars in the Seventh Catalogue of Spectroscopic
Binaries that were found not to show variations with a peak-to-
peak amplitude as great as 0.02 mag. Stars which may show 


                   Table III
  Stars Showing No Variability Greater than DeltaV = 0.02 Mag.
                Numbers in Seventh Catalogue

  2    24*   33*   50   59   72  137  140  189   195
226   273   468?  584  599? 606  626  742  818*  834?
885*  909   920?  948*

?Possible light variation.
*More observations required.



variability near our limit of detection are indicated with queries.
  A summary of the photometric detection of proximity effects
in spectroscopic binaries is in preparation, and we would be
grateful to learn the results of similar searches at other 
observatories.

  We wish to express our thanks to Gunther Schwartz for his
assistance in some of these observations and George B. Field,
Director of the Center for Astrophysics, for allocating some of
the funds that supported this work.

       RICHARD E. McCROSKY and CHARLES A. WHITNEY
              Center for Astrophysics
               Cambridge, MA 02138



Reference:

Batten, A.H., Fletcher, J.M., and Mann, P.J., 1978, Pub. Dom.
    Astrophys. Obs., 15, 121-295. [BIBCODE 1978PDAO...15..121B ]