COMMISSION 27 OF THE I. A. U.
      INFORMATION BULLETIN ON VARIABLE STARS
                  Number 1596

                               Konkoly Observatory
                               Budapest
                               1979 May 2





  THE SPECTRUM OF THE SUSPECTED VARIABLE Gl 851.1 (BD+30d4633)


   Photoelectric data obtained by Krisciunas (1976) had indicated some
peculiarities regarding Gliese 851.1. The star, having spectral type dM0e
in Gliese's catalog, was suspected to be variable by a few hundredths of a
magnitude. Furthermore, the colors [(B-V) = 1.17, (U-B) = 1.12] were rather
blue for the assigned spectral type, and with the listed parallax, the star
is a full magnitude below the MS in the color-magnitude diagram.
   At Dr. Krisciunas' suggestion, we obtained a 40 A mm^-1 spectrogram of
the red region of Gl 851.1 at Ritter Observatory on 21 August 1978. The star
appears unremarkable in the red; there is no trace of Halpha emission, and the
spectral type is dM0-1. We note that a recent blue spectral type by Joy and
Abt (1974) is simply dM0, thus confirming that no hydrogen emission is visible.
The "e" designation in the spectral type in Gliese's catalog then refers to the
presence of only Ca II H and K emission. Gl 851.1 is then almost certainly not
a BY Draconis variable, as the BY Dra stars of this spectral type all have
emission visible at Halpha. Though a few dM stars without Balmer emission are known
to flare (e.g., SZ UMa), such objects have very low rates of flare activity,
and it seems unlikely that Gl 851.1 could be a flare star. The nature of the
variability of Gl 851.1 and its atypical color indices and absolute magnitude
remain unclear.




                           BERNARD W. BOPP
                           Ritter Observatory
                           University of Toledo
                           Toledo, OH 43606 U.S.A.



References :

Joy, A.H. and Abt, H.A. 1974, Astrophys. J. Supp., 28, 1. [BIBCODE 1974ApJS...28....1J ]
Krisciunas, K. 1976, J. Am. Assoc. Var. Star Obs., 5, 74. [BIBCODE 1977JAVSO...5...74K ]