COMMISSION 27 OF THE I.A.U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                             Number 3212

                                                         Konkoly Observatory
                                                         Budapest
                                                         7 July 1988

                                                         HU ISSN 0374 - 0676


                   BV OBSERVATIONS OF HU TAURI

The variable star HU Tau (HR 1471, BSV) was recognized as an eclipsing binary
by Strohmeier and Knigge (1960). Photoelectric light curves of the system
have been observed by Tumer and Kurutac (1979). Parthasarathy and Sarma
(1980) and Melendo (1985). However, none of these could cover the whole
phases satisfactorily.
   With the purpose to obtain BV light curves covering the whole phases,
HU Tau was photoelectrically observed with the 15-cm refractor of Kakuda
Women's Senior High Scool during thirty-four clear nights in 1986 and 1987.
The photometer is furnished with a Hamamatsu 1P21 photomultiplier tube,
Schott filters (GG385+BG12 for B and GC495 for V), a high-quality IC
amplifier and a personal computer for output reading. HR1375 (V=5.99,
B8IV-V) was used as the comparison star and HR1497 (V=4.29, B3V) as the
check star. A total of 957 individual observations in V and 944 in B were
obtained. All these observations in m_var-m_comp are plotted in Figure 1.
   During the observations, three primary minima were observed with the
following epochs:

     JD(Hel) 2446485.9948 +/- 0.0003
                6815.0052 +/- 0.0013
                6849.9584 +/- 0.0003

   Combining with the previous epochs of primary minimum observed photoelectrically 
by Wood (1977), Tumer and Kurutac (1979) and Parthasarathy and Sarma
(1980), the period can be revised as

          Min I = JD(Hel) 2446485.9967 + 2.0563056d E.

   The O-C values computed with this new ephemeris are given in the following
table.
   The depths of both minima in Figure 1 are found to be 0.830m(V) and 0m.868
(B) for the primary minimum and 0m.069 (V) and 0.050m (B) for the secondary
minimum, respectively.

                            [FIGURE 1]

             Figure 1.  BV light curves of HU Tau.

            
                            Table I

JD(Hel)            E         O-C           Observers (photoelectric)

2440981.261      -2677     -0.0056      Parthasarathy and Sarma (1980)
   1012.113      -2662      0.0018                  "
   1275.310      -2534     -0.0083                  "
   1707.145      -2324      0.0025                  "
   1984.745      -2189      0.0013              Wood (1977)
   1986.801      -2188      0.0010                  "
   1990.914      -2186      0.0013                  "
   1992.970      -2185      0.0010                  "
   3833.3662     -1290      0.0037         Tumer and Kurutac (1979)
   3835.4228     -1289      0.0040                  "
   3837.4797     -1288      0.0046                  "
   6455.9948         0     -0.0019            Present paper
   6815.0052       160     -0.0004                  "
   6849.9584       177     -0.0044                  "

   Preliminary analysis of the present light curves with Kitamura's (1965)
incomplete Fourier method yields the geometrical elements i=77deg, r_a=0.18 and
r_b=0.28, with E_pr=0.235 and E_sec=0.109 which indicates that the primary
minimum should be due to the occultation and the secondary due to the transit.
The data of the individual observations given in m_var-m_comp (B, V) are
available upon request.
    I would like to express my hearty thanks to Prof. M. Kitamura of Tokyo
Astronomical Observatory for his suggestion of the present programme and kind
guidance during the course of the present work. Thanks are also extended to
Prof. T. Ohki of Fukushima University for his constant encouragement during
my observations.


                              YOSHIHARU ITO

                    Member of Japan Amateur Photoelectric
                        Observers Association (JAPOA)
                      Kakuda Women's Senior High Scool,
                       Nakajima-kami 25U, Kakuda-City,
                       Miyagi-Prefecture, 981-15 Japan



References:

Kitamura, M., 1965, Advances in Astron. Astrophys. Vol.3, Academic Press,
      New York.
Melendo, E.G., 1985, I.A.P.P.P. Com. No. 20. [BIBCODE 1985IAPPP..20...27M ]
Parthasarathy, M. and Sarma, M.B.K., 1980. Astrophys. Space Sci. 72, 477. [BIBCODE 1980Ap&SS..72..477P ]
Strohmeier, W. and Knigge, R., 1960, Veroff. Bamberg, 5.
Tumer, O. and Kurutac, M., 1979, I.B.V.S. No. 1547.
Wood, D.B., 1977, (cited in Parthasarathy and Sarma's (1980) paper).