COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                      Number 1833

                                  Konkoly Observatory
                                  Budapest
                                  1980 August 28

                                  HU ISSN 0374-0676

                      93 LEONIS

   Hall et al.(1980) have recently announced that the light of 93 Leonis
is variable. They have classified the system as an RS CVn binary.

   This system has been observed spectroscopically from Victoria since
1976 in an attempt to determine velocity amplitudes for both components.
Measurements made so far indicate that Cannon's value for the period was
remarkably accurate. Any given value for the velocity occurs 2d-3d
earlier than predicted from his ephemeris. About 355 cycles separate the
Victoria observations from Cannon's epoch, so the period is probably not
more than 0d008 shorter than his value.

   The composite spectral type was first recognized by Slettebak (1955),
who gave A + G5 III-IV as an approximate classification. On the Victoria
spectrograms, the relative prominence of the Balmer series increases
towards the UV. In the normal photographic region, the three Balmer lines
are just strong enough to explain why earlier observers classified a
G-type spectrum as F8. Slettebak's classification is probably still the
best that can be made. Thus, the secondary component is the one of
earlier spectral type. It probably is also the less massive star of the
pair, but velocity measurements of it are still very uncertain.

   The emission at H and K detected by Young and Koniges (1977) is not
obvious on any of the Victoria plates, but fairly certainly present on
those obtained in 1978. That it originates in the early-type secondary is
unlikely: it must almost certainly be part of the spectrum of the
component measured by Cannon. It may vary in strength, but, since the
Victoria spectrograms are of different dispersions and densities, no
variation can yet be considered established.

   The system is undoubtedly an interesting one, and the variation of
its light is a significant new discovery. Assigning 93 Leonis to the
RS CVn group, however, seems questionable. Spectroscopic observations are
continuing at Victoria.




                    A.H. BATTEN
                    Dominion Astrophysical Observatory,
                    5071 W. Saanich Road,
                    Victoria, B.C., V8X 4MG

References :

Hall, D.S., Henry, G.W., Landis, H.J., Louth, H., Montle, R.E.,
   Skillman, D.R., and Vaucher, C.A. 1980, Inf. Bull. Var. Stars No. 1798.

Slettebak, A. 1955, Astrophys. J., 121, 653. [BIBCODE 1955ApJ...121..653S ]

Young, A., and Koniges, A. 1977, Astrophys. J., 211, 836. [BIBCODE 1977ApJ...211..836Y ]