COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2687

                                   Konkoly Observatory
                                   Budapest
                                   19 March 1985

                                   HU ISSN 0374 - 0676




     CONFIRMATION OF THE 525 DAY PERIOD VARIABILITY FOR HD 2453



   On the basis of the probable spectrum and magnetic variability suggested
by Babcock (1958), photoelectric observations of HD 2453 were carried out at
the stellar station of the Catania Astrophysical Observatory. The measurements
were performed from 1970 through 1974 at a 30 cm telescope in the UBV natural
system using the equipment described in Blanco et al. (1978). The comparison
stars were HD 1439 (C1; HR71 ; A1V) and HD 952 (C2; HR 44 ; A1V). A plot of
the magnitude differences C1- C2 did not show any variation. Magnitude 
differences between HD 2453 and the comparison stars have been computed in each

                            [FIGURE 1]

   Figure 1. Light and colour variations of HD 2453 plotted vs.
   phase computed by means of formula (2). DeltaV is Delta m in V light
   computed by means of formula (1); Delta(B-V) is computed as DeltaB-DeltaV.
   Codes as follows: (dot) 1970, (x) 1971, (o) 1972, (diamond) 1973,
   (triangle) 1974.

colour by means of the formula;

     Delta m= 1/2((Ap-C2)+(Ap-C1)+<C1-C2>)       (1)

where <C1- C2> is the annual average value of the magnitude differences
between the comparison stars.
  Search for variability on a time scale of months or shorter did not get
results. The best representation of the observations is obtained by phasing
them with the Wolff's 525 day period : we obtain light curves showing small
amplitude variations in DeltaV and even smaller in DeltaB and DeltaU. 
In Figure 1 the
DeltaV and Delta(B-V) variations are plotted versus the phase computed by means of
the ephemeris (Wolff, 1975):

     J.D. (magnetic minimum) = 2442288 + 525d * E           (2)

  It is evident from the Figure that the DeltaV and Delta(B-V) variations are
opposite in phase, the Delta(B-V) being in phase with the magnetic field
intensity variation.



                     F.A. CATALANO ^1,2 and S. VACCARI ^2

                    1. Istituto di Astronomia, Universita
                      di Catania, Italy
                    2. C.N.R.- Gruppo Nazionale di Astronomia
                      Unita di Ricerca di Catania, Italy



References:

Babcock, H.W., 1958, Astrophys. J.Suppl., 3, 141. [BIBCODE 1958ApJS....3..141B ]
Blanco, C., Catalano, F.A., and Strazzulla, G., 1978, Astron. Astrophys.
   Suppl., 31, 205. [BIBCODE 1978A&AS...31..205B ]
Wolff, S.C., 1975, Astrophys. J., 202, 127. [BIBCODE 1975ApJ...202..127W ]