COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 2834

                                 Konkoly Observatory
                                 Budapest
                                 13 December 1985

                                 HU ISSN 0374 - 0676



 PHOTOMETRY AND SPECTROPHOTOMETRY OF SYMBIOTIC STARS :
    CI Cyg, Z And, V 1016 Cyg, HM Sge, HBV 475




   Plates of the above mentioned symbiotic stars which
were taken in July and October 1982 at the Observatoire
de Haute Provence, were spectrophotometrically reduced.
The S20 Image tube RCA was used in conjunction with the
spectrograph. The II aO plates which were taken with a
grating spectrograph covered the region lambda, 3700 - 5200 A.
The reciprocal dispersion was 93 A/mm at Hgamma. The II a0
calibration plates were taken on the same nights as those
of the symbiotic stars. The symbiotic stars' spectra were
recorded using the Chalonge Microphotometer at the Lyon
Observatory. The latter converted the plate transmission
to intensities using the characteristic curves. The width
of the Microphotometer slit was set at 25 micron.
   The position of the continuous spectrum is not well
defined for symbiotic stars on account of the presence
of absorption bands (TiO) and emission lines.
   The continuum energy distribution has been compared to
the standard star delta Cyg in the blue spectral range, but
the measurements do not fit well; neither do they agree
with the nature of the M star.
   Relative intensities of emission lines were measured
on the spectrograms. The spectrophotometric corrections
were made by using an intensity trace spectrum of delta Cyg
taken on the same night.


                         Table          I

                             V           B-V      U-B
CI Cyg        22.7.82    10.51+-0.04    + 1.20   - 0.26
              15.10.82   11.24+-0.01    + 1.95   - 0.52
V1016 Cyg     27.7.82    11.23+-0.01    - 0.03   - 0.86
HM Sge        26.7.82    11.45+-0.02    + 0.13   - 0.40
Z And         23.7.82    10.54+-0.01    + 1.37   - 0.39
HBV 475       21.10.82   11.12+-0.04    + 2.34   - 0.91


  The photometric observations of these stars were
carried out with the Polarimeter II described by Chevreton et al.
(1977). The magnitudes and colour indices are given
in Table I and photoelectric observations are plotted
on a two-colour diagram (Figure 1).

HBV 475 : the line of He II lambda 4686 A is very strong
    whereas lambda 3760 A of [Fe VII] is absent
    lambda 5007 A > lambda 4363 A ; He I triplets < singlets
    HI lines are conspicuous up to HII.


Z And : Most emission lines of Fe II and He I (singlets
    + triplets) appear. HI lines are strong.
    He II lambda 4686 A < Hbeta and [OIII] lines are absent.

V 1016 Cyg : the strong emission lines are always present.
    The strongest lines are those of HI, He I, He II,
    [OIII], [NeIII], [FeVII] and [FeVI].

HM Sge : strong emission lines corresponding to V 1016
    Cyg. We note that the [Fe VII] and Fe II lines
    were absent on 27th October.

CI Cyg : the forbidden lines of [Ne III] lambda 3868 A,
    [Fe VII] lambda 3760 A, [OIII] lambda 4363 A, N1 and
    N2 and He II lambda 4686 A are not affected by
    eclipse effects. (B-V) varied from +1.20 (out
    of the eclipse) to 1.88 (middle of the
    eclipse) while (U-B) varied from -0.26 to
    0.11 (Martel, 1982).


                       [FIGURE 1]


    The spectra have been de-reddened by
    Mikolajewska et al. (1983). We have taken 
    E(B-V)=0.45 in agreement with the measurements
    derived from low resolution I.U.E. spectra
    E(B-V)=0.40).
    The M star varied from M5V on 22.7.82 to 
    M6III on 15.10.82  TiO bands (1-0, 2-0, 0-0) 
    are weak.
    Treating the sources as blackbody radiators, 
    we obtain approximate temperatures as follow: 
    4550K for CI Cyg, 11000K for V1016 Cyg and 
    13500K for HBV 475; all three observed on the 
    night of 15.7.82 .
    The ionized gas cloud (with an electron 
    density ne=~ 10^7 cm^-3) suggest a temperature 
    somewhere in the range 
    12000K < Te < 20000K for CI Cyg, HM Sge,
    V 1016 Cyg and HBV 475.



                        R. GRAVINA
                     Observatoire de Lyon
                  69230 Saint-Genis-Laval
                         France


References: 

Chevreton, M., Gravina, R., Martel, M.T., Vanderriest, Ch.,
    Astron. & Astrophys. 54, 627, (1977) [BIBCODE 1977A&A....54..627C ]
Martel, M. T. private communication (1982)
Mikolajewska, J., Mikolajewski, M., Acta Astron., 33, (1983) [BIBCODE 1983AcA....33..403M ]