COMMISSION 27 OF THE I.A.U.
              INFORMATION BULLETIN ON VARIABLE STARS
                           Number 1296

                                                    Konkoly Observatory
                                                    Budapest
                                                    1977 June 27


Omicron ANDROMEDAE: NO CONSPICUOUS RADIAL-VELOCITY VARIATIONS

Recently, Fracassini, Pasinetti and Pastori (1977) published 
an analysis of the radial-velocity behaviour of Omicron And based
on prism spectrograms (dispersion 35 A/mm at H-gamma) obtained at the
Merate Observatory in the years 1967-76. In particular, they 
announced a steep decrease of the hydrogen radial velocity in 
November 1975. While almost all radial velocities of Omicron And published 
since 1900 by several authors fall into a range from 0 to
-30 km/s, some of the velocities published by Fracassini et al.
are as low as -100 km/s. The above authors conclude from it that
there is a 23.5-year periodicity in radial velocities of Omicron
And, possibly connected with appearance and disappearance of shell
lines in the spectrum of this star.
   Since Koubsky's (1975) discovery of the hydrogen shell lines
in the spectrum of Omicron And, a large collection of grating spectrograms 
of the star (dispersion 8.5 A/mm, range 3550-4900 A) has
been secured at the coude focus of the Ondrejov 2-m telescope.
Some of them were obtained on the same nights as the spectrograms 
used by Fracassini et al. We measured radial velocities
of these spectrograms using the Zeiss Abbe Comparator equipped
with a small projection screen. The settings were done on the
cores of sharp hydrogen lines. As it is not quite clear to which
part of the hydrogen profiles refer the data published by Fracassini 
et al., we also obtained rectified intensity profiles
of the H-gamma line (most of the analyses by Fracassini et al. are
based just on the H-gamma velocities) and measured radial velocity
of the H-gamma wings relative to the shell core. The accuracy of this
quantity is somewhat lower than the accuracy of the shell velocities 
measured with the comparator. As it can be seen in Fig. 1,
we were not able to confirm large negative velocities found by
Fracassini et al. Radial velocity of the H-gamma line of Omicron
And was close to -25 km/s for the cores, and to -24 km/s for the
wings of the line (very probably this difference is unsignificant),
with possible variations +-10 km/s around these values. According 
to our data, this was true not only in autumn 1975 but also
during 1976; invariably for all the shell hydrogen lines. 
Consequently, the conclusions presented by Fracassini et al. (1977)
should be critically re-examined. We appeal to observers from
other observatories who obtained some high-dispersion spectrograms 
of Omicron And during the critical period (October-December
1975) to publish their radial velocities soon.
   As a by-product of our study we have found definite variations 
of the central intensity of the H-gamma line between two 
subsequent nights (see Fig. 2). Notably, Bolton and Gulliver (1976)
reported intensity variations of metallic lines of Omicron And on the
same time scale. There is some indication that the H-gamma central
intensity may vary regularly, with a period of 3.66 days.
Presently, we are analyzing more H-gamma profiles to check on this
point. A more detailed analysis of our about eighty coude spectrograms 
of Omicron And will be published later in Bull. astr. Inst.
Czechoslovakia.


                  P. HARMANEC, P. KOUBSKY, J. KRPATA,
                    F. ZDARSKY and A. DOLENSKA

                Astronomical Institute of the Czechoslovak
                        Academy of Sciences
                   251 65 Ondrejov, Czechoslovakia



References:

Bolton, C.T., Gulliver, A. (1976) IAU Circular No. 2899 [BIBCODE 1976IAUC.2899....4B ]
Fracassini, M., Pasinetti, L.E., Pastori, L. (1977) Astrophys. Spa. Sci.
   (in press).
Koubsky, P. (1975) IAU Circular No. 2802 [BIBCODE 1975IAUC.2802....3K ]


                         [FIGURE 1]

  Fig. 1: Comparison of Hgamma radial velocities of o And obtained at 
 Ondrejov and Merate Observatories at the end of November,, 1975.
 Following symbols are used:
       (dot) - Ondrejov, core of the line (Abbe)
         o   - Ondrejov, wings of the line (rectified intensity tracings)
  (triangle) - Merate


                         [FIGURE 2]

  Fig. 2: Central intensities of the Hgamma line of o And during November 
23-26, 1975.