COMMISSION 27 OF THE I.A.U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                             Number 3220

                                                         Konkoly Observatory
                                                         Budapest
                                                         27 July 1988

                                                         HU ISSN 0374 - 0676


      ON THE PERIOD OF THE LIGHT VARIATIONS OF THE Mn STAR HD 27295

The star HD 27295 (HR 1339=53 Tau, B9 Mn) was used as a comparison in the
observations of HD 27962 carried out in 1973 and 1974 at the stellar station
of the Catania Astrophysical Observatory. The observations were made in the
UBV system using the 90 cm telescope and the equipment described in Blanco et
al. (1978).
   From a first analysis of the observations it was evident that the dispersion
of the measurements of HD 27295 was larger than allowed for a comparison star,
so this star was eliminated from the programme.
   From UBV observations made some years before, Winzer (1974) derived a period
of 4.302 days using HD 27176 (HR 1331 = 51 Tau, F0V) as a comparison star. This
period is very close to the orbital period of 4.452064 days found by Dworetsky
(1972) from spectroscopic observations.
   Since our measurements were too few to look for a period determination, but
not too far in time from Winzer's observations we decided to use our
observations together with Winzer's ones to check or improve his period. To
this end we used the second comparison in the programme of HD 27962, i.e. HD
27934 (HR 1387 = 65 Tau, A7IV), which in turn was found to be a suspected delta
Sct star in the literature. However, during our observing session, HD 27934
showed a small dispersion, of the order of the natural dispersion, so it proved
to be suitable to be used as a comparison star. After transforming our set of
data into Winzer's system, we searched for periodicity by means of computer
programmes (Deeming 1975, Breger 1982) which have been recently available to
us. The best representation of data has been obtained with the period of
4.424125 days; which is close to Winzer's (1974) value. The resulting light
curve in U is reported in Figure 1, The ephemerides used are:

       JD (U max) = 244 1992.553 + 4.424125d E                    (1)

No reliable light curve is obtained when using the spectroscopic binary period
by Dworetsky (1972).


                          [FIGURE 1]

 Figure 1:  U light curve of HD 27295. The phase is computed
            according to formula (1). Circles denote observations
            by Winzer (1974), crosses denote ours.



   F.A. CATALANO 1,3     F. LEONE 2,3     S. VACCARI 3

1. Istituto di Astronomia dell'Universita di Catania
2. Osservatorio Astrofisico di Catania
3. C.N.R. - Gruppo Nazionale di Astronomia,
   Unita di Ricerca di Catania, Italy



References:

Blanco, C.,  Catalano, F.A., Strazzulla, G., 1978, Astron. Astrophys. Suppl.
     31, 205. [BIBCODE 1978A&AS...31..205B ]
Breger, M., 1982, Vienna Internal Report, 82/2.
Deeming, T.J., 1975, Astrophys. Space Sci. 36, 137. [BIBCODE 1975Ap&SS..36..137D ]
Dworetsky, M.M., 1972, Publ. Astron. Soc. Pacific 84, 652. [BIBCODE 1972PASP...84..652D ]
Winzer, J.E., 1974, Thesis - University of Toronto. [BIBCODE 1974PhDT........61W ]



                        [From IBVS 3281]


                               ERRATUM

In the ephemerides of the U light curve of HD 27295 (IBVS No. 3220) the
initial epoch refers to the minimum light instead of the maximum light
given by a clerical mistake.


                 F.A. CATALANO and F. LEONE