COMMISSION 27 OF THE I.A.U.
      INFORMATION BULLETIN ON VARIABLE STARS
                   Number 150

                                       Konkoly Observatory
                                       Budapest
                                       8 August 1966

        OBSERVATIONS OF VARIABLE F-TYPE STARS
                 WITH SHORT PERIODS



      After extended UBV photoelectric observations of about 70
bright field F stars, made between October 1965 and February 1966
with the Mount Wilson 60-inch and Palomar 20-inch reflectors, the
following stars were found to show short period, small amplitude
light variations. Approximated periods are given in parentheses:
- HR 1287 (0.134d), HR 1706 (0.122d), HR 2107 (0.137d), HR 3265 (0.13d)
HR 3888 (0.13d), HR 4715 (0.169d)+/, HR 5005 (0.14d), and HR 5017
(0.14d). Some variation has also been detected in the star HR 2539 and
in the close binary system HR 3889 although the nature of the variation 
is uncertain. There is strong evidence that the light amplitudes
of most of the stars listed are changing in the manner shown by some
of the known Delta Scuti stars.
      More extensive observations with the Cassegrain photoelectric 
spectrum scanner on the Mount Wilson 60-inch and the Coude
spectrograph on the 100-inch have been completed to determine 
effective temperatures, surface gravities, masses and pulsation 
characteristics of these stars. A number of non-variable stars in the
same region of the Colour-Magnitude Diagram have also been 
investigated to look for possible differences in physical characteristics
between variable and non-variable stars.
      The UBV observations of HR 1287 and HR 2107 were made in
collaboration with Dr. A. R. Sandage.


Mount Wilson and Palomar Observatories,
July 29, 1966
                                 I. J. DANZIGER
                                 R. J. DICKENS


  +/ HR 4715 = 4 CVn was found to be variable in radial velocity with a
     period of 0.17d by Jones and Haslam (Observatory 86, 34, (1966)
     Photoelectric observations of this star have been already published
     by Wachmann (IBVS 138).   [BIBCODE 1966IBVS..138....1W ]