COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      Number 1113

                                 Konkoly Observatory
                                 Budapest
                                 1976 March 9



 BS 1099: A BRIGHT VARIABLE SIMILAR TO THE RADIO STAR UX ARIETIS



   Photoelectric observations of BS 1099 (= ADS 2644 AB = CSVS
6039) have shown it to be a variable. We (along with Larry P. Lovell
at the Hickox Observatory in Chagrin Falls, Ohio) plan to continue
observing this variable until it sets and then publish our observations 
together elsewhere.
    Between JD 2,942,748.5 and JD 2,442,808.5 Landis obtained 21
observations with his 10-inch (25-cm) Newtonian reflector, and 
between JD 2,442,816.5 and JD 2,442,831.5 Hall obtained 7 with the
24-inch (60-cm) Seyfert reflector of the Dyer Observatory. Both 
observers used a visual filter, included both components of the visual 
binary system, and used 10 Tauri as a comparison star. Extraterrestrial 
instrumental differential magnitudes are plotted in the
Figure, where the 0.015M shift between those of Landis (delta v_L ) and
those of Hall (delta v_H) allows for the difference in transformation to
the UBV system. Phase is computed with the ephemeris

         JD (hel.) = 2,442,770.65 + 2.822d E

for minimum light. The UBV photometry of Cousins (1963) made him
suspect that BS 1099 was a variable with an amplitude of deltaV = 0.11m,
which is exactly what our photometry shows.

                       [FIGURE 1]

    We are extremely grateful to Dr. Bernard W. Bopp for drawing
our attention to the fact that BS 1099 resembles UX Arietis 
spectroscopically. According to him it shows a pronounced H and K 
reversal similar to that seen in other RS CVn-type binaries and it
seems to be a spectroscopic binary with an orbital period in the
neighborhood of 3 days. Now, comparing our Figure with Figure 1 of
Hall, Montle, and Atkins (1975), we see also that the light curves
of BS 1099 and UX Ari are amazingly similar.
    The radio astronomers will want to look for radio emission
similar to that found emanating from UX Ari (Gibson, Hjellming and
Owen 1975), since BS 1099 is brighter than UX Ari and even brighter
than AR Lacertae. In fact, BS 1099 seems to be the brightest RS CVn-
type binary known to date (Hall 1976).
    In a recent phone conversation Dr. Bopp has just told us that
his April-December 1975 spectroscopic observations have yielded an
orbital period of 2.8379d +- 0.0003d.


HOWARD J. LANDIS        DOUGLAS S. HALL
Landis Observatory      Dyer Observatory
2395 Wood Hill Lane     Vanderbilt University
East Point,             Nashville,
Georgia 30344, U.S.A.   Tennessee 37235, U.S.A.


References:

    Cousins, A.W.J. 1963, M.N.A.S.S.A. 22, 58. [BIBCODE 1963MNSSA..22...58C ]
    Gibson, D.M., Hjellming, R.M, and Owen, F.N. 1975,
         Ap.J. 200, L99.  [BIBCODE 1975ApJ...200L..99G ]
    Hall, D.S. 1976, I.A.U. Colloquium 29. [BIBCODE 1976ASSL...60..287H ]
    Hall, D.S., Montle, R.E. and Atkins, H.L. 1975, Acta Astr.
          25, 125. [BIBCODE 1975AcA....25..125H ]



                    [Correction from IBVS 1117]

           CORRECTION TO I.B.V.S. No. 1113


"10-inch (25 cm)" should be read "8-inch (20 cm)"


                         D.S. HALL and
                         H.J. LANDIS