COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                 NUMBER 858
                          

				Konkoly Observatory
                          	Budapest

                          	1974 January 7

           THE SPECTRUM OF BC DRACONIS


   BC Draconis = Bamberg Variable No.222, found by Strohmeier
(Kl.Ver.Bamberg, No. 23., 1958) and identified as a cepheid with
P = 2.566033 days by Strohmeier and Knigge (Veroff. Bamberg No. 5,
No. 11, p. 5, 1961), has been reported to have a late B spectral
type (Gotz and Wenzel, Mitt.Ver.St., 2 , 85, 1964). Its galactic 
latitude is +28.5.
  In an effort to resolve the apparent discrepancy between the
spectral type and variable class the star was observed with the
36-inch Cassegrain grating spectrograph and Westinghouse image
tube. A spectrogram at 100 A/mm was obtained on each of three nights;
October 23, 24 and 27, 1973. The epoch of maximum and the period
given by Strohmeier and Knigge indicate that the observations were
made at phases .178, .550, and .731 respectively. The low resolution 
of the spectrograms does not permit a luminosity classification 
but all three show the temperature class of the star to be
about F5, consistent with the cepheid interpretation of the light
curve.
  For log P = 0.4 the period-luminosity relation for classical
cepheids (Allen, Astrophys. Quantities, 2nd. ed., p. 210, 1963) gives
MB = -2.2. The photographic interstellar extinction in the region
of BC Draconis is approximately 1.1 magnitudes (Shane and Wirtanen,
Pub. Lick Obs., 22, part 1, 1967). Therefore, from its mean apparent
photographic magnitude of 11.7 the star is found to be at a 
distance of 3630 pc and 1730 pc above the galactic plane. From the
period-luminosity relation for W Virginis stars (M_B = -0.9) the
corresponding distances are 2000 pc and 950 pc. It appears that
the star is a Population II cepheid although this has not been
confirmed spectroscopically.


Warner and Swasey Observatory               NELSON J. IRVINE
Case Western Reserve University
E. Cleveland, Ohio, U.S.A.