COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2669


                                   Konkoly Observatory
                                   Budapest
                                   18 February 1985

                                   HU ISSN 0374 - 0676

      H_alpha EMISSION IN RS CVn STARS: BD+61d 1211 AND HD 37847


  In addition to the 33 RS CVn stars (Liu Xuefu and Tan Huisong, 1984), other
29 RS CVn stars were observed in the H_alpha region using the Coude Reticon system of
the McDonald Observatory 2.1 m telescope. The dispersion is 9.5 A/mm and 
the resolution is 0.29A. These observations were made in Nov. and Dec., 1984. Two of the
observed stars, BD+61d 1211 and HD 37847, showed Halpha emission. The basic 
data are listed below.

---------------------------------------------------------------------
Star            Sp.       Period  Obs.J.D.(H)  Phase   H E.W.  (mA)
                          (day)   2446000+             emis.   absor.
---------------------------------------------------------------------
BD+61d 1211     late G    7.492   35.9513      0.830     2040      0
            or early K            36.0367      0.842     2030      0
                                  36.8954      0.956     2000      0
                                  36.9929      0.969     1840      0
                                  37.9963      0.103     2923      0
HD 37847      F(pri.)      -      33.7954       -          60    100
              G8III(sec.)         34.7838       -           0    464
                                  35.7433       -           0    835
                                  36.7408       -           0    767
                                  36.7788       -           0    767
                                  27.9229       -           0    564
---------------------------------------------------------------------



BD+61d 1211=DM UMa=SAO 015339, has been indentified as the optical counterpart to
the x-ray source 2A1 052+606 by Liller (1978). He found by HEAO-1 that this
binary has moderate H_alpha emission. Crampton (1979) also observed the 
Halpha emission using a scanner with 8-10A resolution.
  We report here five high-resolution observations (Figure 1), all of them show
strong emission. It is known that HR 1099, II Peg, HD 8357 and BD+61d 1211 are
the objects to emit both hard and soft x-rays and always show H_alpha emission. This
is characteristic of only the most active RS CVn stars.
  HD 37847 has no H_alpha emission reported yet. The H_alpha profiles in this paper show
gradual change over five nights (Figure 2). H_alpha emission appears slightly above
the continuum only during the first night. Obviously, the absorption component
is filled up by the emission one since the equivalent width of the absorption
component of H_alpha is much less than that of the normal star in the same spectral
type and luminosity class.

                          [FIGURE 1]

   Figure 1. Halpha emission feature of BD +61d1211

                          [FIGURE 2]

   Figure 2. Halpha emission feature of HD 37847

  We are grateful to Dr. H. Smith for scheduling the telescope time.





                            TAN HUISONG and LIU XUEFU

                            McDonald Observatory, The
                            University of Texas
                            (visiting scholars from China)





References :

Crampton, D., 1979, Ap.J., 234, 993 [BIBCODE 1979ApJ...234..993C ]
Liller, W., 1978, IAU Circ., No. 3176 [BIBCODE 1978IAUC.3176....2L ]
Liu Xuefu and Tan Huisong, 1984, IBVS 2606