COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1919

                                  Konkoly Observatory
                                  Budapest
                                  1981 February 5

                                  HU ISSN 0374-0676



                 A NOTE ON BZ ERIDANI


    In this communication, first photoelectric photometry of the system
BZ Eridani in three colours and some tentative results have been
presented.
    Observations were carried out through the 38-cm reflector,
employing 1P21 photomultiplier thermoelectrically cooled
to -20degC, the UBV filters of Johnson and Morgan system and d.c.
techniques.
    A total of ten nights of observations have been secured. during 
the period December 1975 to March 1976, using BD-6d 840 and
BD-6d846 as comparison and check stars, respectively. Instrumental 
magnitudes have been standardized with the observations of
four standard stars (omega Eri, mu Eri, nu Eri and epsilon Eri). Accuracy of 
individual observation in U, B and V filters are respectively,
+-0.035m, +-0.032m, and +-0.024m.
    During the course of our observations two primary and one
secondary minima have been obtained with a graphical accuracy of
+-0.001d in time.
    Using the epoch, JD 2425558.445 (Meinunger, 1966), a new
period of 0.6641701d has been determined which is not significantly 
different from that of Meinunger (1966), 0.6641704d. Kippenhahn
(1955) has given a slightly different epoch, JD 2425558.456, from
that of Meinunger (1966).

    From the light-curves (Figure 1), we find that:
(1) The depth of primary minimum is nearly half of that given by
    Hoffmeister (1934) and Meinunger (1966).
(2) The duration of eclipse is nearly half of the value given by
    Meinunger (1966).
(3) The depth of secondary minimum is nearly half that oil the
    primary.


                            [FIGURE 1]

  Fig. 1.  Light and colour curves of BZ Eridani (Filled and open
           circles represent direct and reflected points, respectively)

   The secondary eclipse seems to be a total (occultation)
with a duration of totality about 1.2h.
   The colours of both the components of the system have been
obtained. These, on comparing with Arp's (1958) colour-sequences,
indicate that the primary and the secondary components belong to
G0III and G2III spectral types, respectively. The systemic colour
is of G1III type, which is considerably different from that given 
by Gotz and Wenzel (1961), F2.
    In order to decide on the type of light curve, present
light curve characteristics have been compared with those listed
by Strohmeier (1972). It is found that our light curve shows
some similarity with that of W UMa type light curve, but on the
whole it is closer to Algol type as suggested by Hoffmeister
(1934).

		Summary of results
Amplitude of primary minimum   : 0.42m(U), 0.48m(B), 0.44m(V)
Amplitude of secondary minimum : 0.20m(U), 0.21m(B), 0.23m(V)
Times of primary minima        : JD 2442836.164(+-0.001)
                                 JD 2442840.155(+-0.001)
Time of secondary minimum      : JD 2442835.172(+-0 001)
Duration of eclipse (D)        : 7.2h(U), 5.6h(B), 5.6h(V)
Duration of totality (d)       : 1.6h(U), 0.8h(B), 1.1h(V)
Spectral type of primary
component                      : G0III(B-V=+0.644m, U-B=+0.326m)
Spectral type of secondary
component                      : G2III(B-V=+0.682m, U-B=+0.513m)
Combined spectral type of
both the components            : G1III(B-V=+0.664m, U-B=+0.336m)
Spectral type of comparison                                
star (= -6d840)                : F6I(B-V=+0.524m, U-B=+0.436m)

We are thankful to Dr. C.D. Kandpal for his helpful discussions.


		R.K. SRIVASTAVA and B.K. SINHA
		Uttar Pradesh State Observatory,
		Manora peak, Naini Tal - 263129,
		India.


References:

Arp, H.C., 1958, Handbuch der Physik 51 83. [BIBCODE 1958HDP....51...75A ]
Hoffmeister, C., 1934, Astron. Nachr. 253 (6058), 196 [BIBCODE 1934AN....253..195H ]
Gotz, W. and Wenzel, W., 1961, Mitt. Veranderl Sterne, 529.
Kippenhahn, R., 1955, Astron. Nachr. 282, 75. [BIBCODE 1955AN....282...73K ]
Meinunger, L., 1966, Mitt. Veranderl. Sterne 3, 200.
Strohmeier, W., 1972, Variable Stars, Pergamon Press, Oxford,
   185. [BIBCODE 1972vast.book.....S ]