COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1549

                                  Konkoly Observatory
                                  Budapest
                                  1979 February 12




           THE SPECTRAL TYPE OF BQ SERPENTIS


     In the course of our observation of double mode Cepheids,
several spectrograms of BQ Ser^1) have been obtained at the Okayama
Astrophysical Observatory. The observations were carried out on
July 1978 with the use of image intensifier spectrograph attached
the Cassegrain focus of the 188cm reflector. The dispersion is
about 108A/mm for the first order of the grating. All the plates
were taken with the Kodak 103a-O emulsion. The covered wave length
range is about lambdalambda3900-5400.
     For the spectral type determination, the Balmer H_beta, H_gamma, H_delta
lines and the appearance of G hand were used from a comparison
with the spectra of MK standard stars obtained with same spectrograph. 
Table 1 lists the adopted standard stars. These are taken
from Morgan and Abt^2), Morgan and Keenan^3), and Cowley^4).



                       Table 1
           --------------------------------------
             Adopted MK standard stars
           Standard star Spectral type References
           --------------------------------------
              HR 8025   F1 III   4
              HR 7222   F2 III   2,4
              HR 6577   F6 III   2,3,4
              HR 9057   F8 III   4
           --------------------------------------


     Results are presented in Table 2. The last column gives
the obtained ones from the H_beta,gamma,delta lines and the features of
band, respectively. The errors, based on the uncertainties of
continuum level and the fluctuation of intensity curve, roughly
correspond to the accuracy of 1-2 subdivision of spectral class.
Especially using the H_gamma profile, which is blended by the strong
HgI emission line of city light, lacks the sufficient accuracy.
Because of the above reason, no concerning is paid to the phase
variation.


                   Table 2
             Spectral type of BQ Ser
       -------------------------------------------------
       Plate Date      JD       Spectral type
        No.  1978    2443000+ H_beta,gamma,delta  G band
       -------------------------------------------------
       IS 549 July 8  698.006        F5~F6          -
       IS 550 July 9  698.154        F5~F6          F6
       IS 552 July 14 703.149        F6~F7          F6
       -------------------------------------------------


     In conclusion, the mean spectral type of BQ Ser is F6.
This result gives somewhat late type in comparison with the early
reports of Herbig^5) (F3 III) and Kukarkin et al.^6) (F5 III).
     The author would like to thank Dr. M. Takeuti for helpful
advices. Messrs. S. Egawa and K. Hara are also acknowledged for
their cooperation in the observations.




                           KEIICHI UJI-IYE
                           Astronomical Institute,
                           Tohoku University,
                           Sendai, 980 Japan




References:

1. The precise photometric observations for the star has been
   carried out by L. Szabados (1977, Mitt.Sternw.Ung.Akad.Wiss.,
   Budapest, No. 70) [BIBCODE 1977CoKon..70....1S ]
			[CoKon No. 70]
2. Morgan, W.W. and Abt, H.A., 1972, Astron.J., 77, 35 [BIBCODE 1972AJ.....77...35M ]
3. Morgan, W.W. and Keenan, P.C., 1973, Ann.Rev.Astron.Astrophys.
   11, 29 [BIBCODE 1973ARA&A..11...29M ]
4. Cowley, A. 1976, Publ.Astron.Soc.Pacific, 88, 95 [BIBCODE 1976PASP...88...95C ]
5. Herbig, G.H. 1960, Astrophys.J. 131, 632 [BIBCODE 1960ApJ...131..632H ]
6. Kukarkin, B.V. et al., 1970, Gen.Cat.of Var. Stars, 3rd. ed. Vol. 2