COMMISSION 27 OF THE I. A. U.
       INFORMATION BULLETIN ON VARIABLE STARS
                   Number 1601

                                   Konkoly Observatory
                                   Budapest
                                   1979 May 10

     ON THE VARIABILITY OF HD 66194 AND OF HD 101158



    We report on the photometric variability of two stars observed in
January 1977 at La Silla, Chile using the Bochum University 61 cm telescope.
Observing and reduction procedures follow those outlined by Stift (1978).
    A member of the open cluster NGC 2516, HD 66194 has been classified
B2IVpne_1+ by Hiltner et al. (1969). Being one of the less spectacular 
emission line B-type stars it has been little observed so far. Photoelectric
photometry, mainly carried out by Feinstein (1968) and Dachs (1970), indicates
a total amplitude of DeltaV ~0.10m and marginal colour variations on an unknown
time scale. Photoelectric H_alpha scans have been reported by Dachs et al. (1977);
they suggest variability within a few days. On January 16, 18, 19, 20, and 21
photoelectric observations of HD 66194 were obtained relative to HD 66341,
a B8III star. A gradual fading by ~0.03m in UBV between January 16 - 19 was
followed by an interval of constant brightness from January 19 - 21. The
photometric behaviour of HD 66194 thus appears quite similar to that of
most Be stars with well-known photometric variations : variability occurs on
the time scale of a few days, overall amplitudes rarely exceed 0.1m.
    Classified F0V in the Michigan Spectral Catalogue, HD 101158 is a
southern star of photographic magnitude 7.6m for which no photoelectric
measurements are available. It was used as a secondary comparison star for
differential photometry of Przybylski's star, HD 101065, from January 3 to
January 11. Throughout this observing run HD 101158 displayed low-amplitude
short-term variations. Starting at J.D. 2443149.794 it brightened by 0.04m -
0.05m in UBV in an interval of ~1 hour. Air mass differences and/or
amplifier settings cannot account for such variations; the constancy of the
control star HD 100367, an A0V star, was checked against several other stars.
Thus there is a very strong case for short-term low-amplitude variability of
HD 101158.


                             M.J. STIFT
                             Institut fur Astronomie
                             Universitatssternwarte
                             Wien




References :

Dachs, J.: 1970, Astron. Astrophys. 5, 312 [BIBCODE 1970A&A.....5..312D ]
Dachs, J., Maitzen, H.-M., Moffat, A.F.J., Sherwood, W.A. and Stift, M.:
   1977, Astron. Astrophys. 56, 417 [BIBCODE 1977A&A....56..417D ]
Feinstein, A.: 1968, Z. Astrophys. 68, 29 [BIBCODE 1968ZA.....68...29F ]
Hiltner, W.A., Garrison, R.F. and Schild, R.E.: 1969, Astrophys. J. 157, 313 [BIBCODE 1969ApJ...157..313H ]
Stift, M.J.: 1978, Astron. Astrophys. Suppl. 32, 343 [BIBCODE 1978A&AS...32..343S ]