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

                     NUMBER 545

                              Konkoly Observatory
                              Budapest
                              1971 May 3


	  A NEW VARIABLE STAR IN SERPENS


	Mr. John Kirszenberg, a student at Case-Western
Reserve University, has discovered a new variable star in
Serpens. Figure 1 is a finding chart for the variable, whose
1900 coordinates are RA = 18h14.9m, D = -10d14'. The 
discovery was made while blinking a pair of objective-prism
photographs taken twenty days apart with the 60-90 cm
Burrell Schmidt telescope of the Warner and Swasey 
Observatory. On the earlier plate of the pair, taken August 6.
221, 1970, the spectrum shows narrow, moderately strong
Balmer emission lines and a strong ultraviolet continuum.
The continuum between H-beta and H-gamma is  about three quarters
of a magnitude brighter than on the later photograph where
the spectrum is that of a late K-type star with mpg = 11.5.
There are twenty other photographs of this star in our plate
collection, taken between 1948 and 1983, none of which show
any detectable variation in brightness  or spectrum.

                   [FIGURE 1]

       The type of variability which is observed in this
case is very puzzling. The disappearance of the emission
spectrum suggests a flare type activity, but the vast 
majority of flare stars are of spectral type dMe while this
star is not. Moreover, flare spectra show strong Ca II
emission lines, absent in the spectrum of this star. 
Classification as a U Geminorum or symbiotic variable is highly
improbable in view of its non-variability in the past. The
possibility that the variable is a fainter star nearly 
coincident in position with the K star cannot be ruled out,
but does not appear likely. I have carefully compared the
position of the emission spectrum with that of the K star
and conclude that they are coincident within the errors of
measurement (approximately two seconds of arc).
       The available data suggests that this star may be
similar to Popper's (1953) flare star which has been 
observed to flare only once. Its spectral type is K6V and it
is quiescent most of the time, characteristics which agree
with what is known about the Serpens variable. Its behavior
may also bear some similarity to that of EZ Pegasi, a star
which the General Catalog of Variable Stars calls a unique
object. EZ Pegasi has a normal spectral type of G5; but on
one objective prism photograph from the Leander McCormick
Observatory it shows a spectrum of type B. However, EZ
Pegasi is also an irregular variable with an amplitude of
about one magnitude, a fact which argues against a real
similarity with the variable described here. More observations 
of this star are evidently needed in order to decide
between the various possibilities described above.



                        FRANCIS M. STIENON
                    Warner and Swasey Observatory
                   Case-Western Reserve University




Reference: Popper, D.M. (1953) Publ. A.S.P. 65, 278. [BIBCODE 1953PASP...65..278P ]




Editor's note: Recently S. Cristaldi and M. Rodono have 
observed several flares in Popper's star, BY Dra, Sp K6Ve
(Astron. and Astrophys, 12, 152, 1971). [BIBCODE 1971A&A....12..152C ]