COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      NUMBER 469


                                 Konkoly Observatory
                                 Budapest
                                 1970 October 5


SYMBIOTIC STARS IN SAGITTARIUS EXAMINED FOR VARIABILITY

      A paper by G.H. Herbig, "Emission-Line Objects Projected 
Upon the Galactic Bulge" (Contr.Lick Obs. No. 299:
Proc.Nat. Acad, Sci., U.S.A., 63, 1045, 1969) lists six
probable symbiotic stars not previously examined for
variability that are within or close to the boundaries of
VSF 193 in Sagittarius. Dr. Herbig kindly supplied identification 
charts made from the Palomar Sky Survey. The results
of the examination of the plates available at the Maria
Mitchell Observatory are summarized in the Table. The first
four columns are taken directly from Herbig's paper; in
column 3, SS stands for symbiotic spectrum.


                SYMBIOTIC STARS EXAMINED FOR VARIABILITY
 
Name    R.A.(1900)      Dec     Class   m_mg               Plates
                                             Variability          Observer

T53      18h01m19s7-25 54'23"     SS?   13      Susp.       200       3  
AS 281      04 25.5-27 58 56      SS?   15      Not Var.     50       3
AS 293      08 10.6-29 51 03      SS?   14      13.2-15.2   350     1-2
T21         14 05.5-26 25 17      SS    12      Not Var.    600       2
AS 316      36 33.9-21 23 31      SS    14      Susp.       500       1
MWC 960     42 00.2-20 12 22      SS?   13      Susp.        50       1

1: D. Hoffleit, 2: Martha Clarke, 3: Marcia Keyes

                   Only one of the six stars has been
                   found to be conspicuously variable,
                   AS 293 Merrill and Burwell (Ap.J.
                   112, 72, 1950) described the star
                   as being 1:5 South of CoD -29 
[FIGURE 1]
                   14.700. Figure 1 is an identification 
                   chart based on Nantucket
                   plates having a scale of 248"/mm.
                   The observations, covering the
                   interval July 1957 to September
                   1970, are satisfied by the relation

                     Min = J.D. 2437485 + 243dn.

                  Fig. 1: AS 293 marked with circle.
                  A=CoD-29 14700  B=CoD-29 14714


      Although the period is typical of Mira-type stars,
the light curve is not necessarily of this type. With the
comparatively short duration of minimum (one third of the
period) the star may be somewhat similar to the symbiotic
stars, CI Cygni and AS 313, whose periods, however, are
much longer, 850d (Hoffleit, Irish Astr.Jour., 8 149,1968).
For AS 293 there seems to be some evidence for a shorter
period superposed on the long period. On the other hand,
the star is far from the center of the plates (18h23m,-
23 3) and accidental errors may be large.



                  [FIGURE 2]

          Fig. 2: Light curve of AS 293


      Three of the other stars in the Table are suspected
of variability, as noted in column 5. In all cases the
estimates on our small scale plates were adversely affected
by unresolved optical companions. Plates of higher resolution
are necessary for definitive conclusions.


September 27, 1970

                         DORRIT HOFFLEIT
                     Maria Mitchell Observatory
                          Nantucket
                         Mass., U.S.A.