COMMISSION 27 OF THE I.A.U.
               INFORMATION BULLETIN ON VARIABLE STARS
                            Number 1489

                                                      Konkoly Observatory
                                                      Budapest
                                                      1978 October 17


 NARROW BAND OBSERVATIONS OF THE RS CVn BINARY TY PYXIDIS

Recently studies of TY Pyxidis have been published by Andersen
and Popper (1975) and by Surendiranath et al. (1978). In March
and April 1977 an investigation of several later type stars
suspected to carry star spots has been undertaken. The stars have
been observed with the photometer at the 61 cm Cassegrain telescope 
of the Astronomical Institute of the Ruhr University of
Bochum at the European Southern Observatory in La Silla, Chile.
The photomultiplier was a refrigerated EMI 9502A tube, the 
filters were Johnson's B, at 5125A (Hw 45A), 5170A (Hw 40A), and
6750A (Hw 200A). The narrow bands have been specially selected
for the observation of star spot sensitive spectral regions.
First observations in this colour system have been published by
the author (1978), more detailed studies of the other program
stars are in progress.


                               Table 1

                     All times in JD Hel.+2443240

  t     DeltaB        t    Delta6750         t    Delta5170       t   Delta5125

5.4990   .335       5.4993    .765         5.4997   .540        5.5001   .550
5.5047   .330       5.5009    .750         5.5004   .545        5.5058   .545
6.4892   .480       5.5050    .730         5.5054   .550        6.4905   .685
6.4948   .440       5.5066    .785         5.5062   .540        6.4959   .640
6.5307   .320       6.4897    .795         6.4901   .700        6.5330   .535
8.5833   .325       6.4914    .765         6.4909   .670        8.5855   .575
9.5405   .570       6.4951    .895         6.4955   .640        9.5414   .770
9.5481   .610       6.4968    .910         6.4963   .645        9.5489   .825
                    6.5314    .705         8.5848   .565
                    6.5346    .855         8.5863   .590
                    8.5841    .840         9.5410   .790
                    8.5870    .780         9.5421   .795
                                           9.5485   .820
                                           9.5492   .835

   The observations of TY Pyx are shown in Table 1. Comparison star
was HD 77087. The times of the observations are equivalent to
the phases 0.7, 0.98 and 0.03 using the ephemeris given by Andersen 
and Popper (1975). The color indices do not show any significant 
changes at these phases. Therefore it should be concluded 
that no larger star spots were visible at the time and phases
of the observations.


                       M. HOFFMANN

                   Observatorium Hoher List
               der Universitats-Sternwarte Bonn
                       5568 Daun/Eifel



References:

Andersen, J., Popper D.M. 1975, Astron.Astrophys. 39, 131 [BIBCODE 1975A&A....39..131A ]
Hoffmann, M., 1978, Mitteilungen Astron. Gesellsch. 43, 186 [BIBCODE 1978MitAG..43..186H ]
Surendiranath, R., Vivekananda, Rao, P., Sarma, M.B.K., 1978 Acta Astr. 28, 231 [BIBCODE 1978AcA....28..231S ]