COMMISSION 27 OF THE I.A.U.
              INFORMATION BULLETIN ON VARIABLE STARS
                           Number 2949

                                                    Konkoly Observatory
                                                    Budapest
                                                    31 October 1986

                                                    HU ISSN 0374 - 0676


   DETECTION OF A SATELLITE LINE SYSTEM IN HIGH-DISPERSION SPECTRA OF
                 THE BETA LYRAE TYPE BINARY HD72754

During a spectroscopic research on peculiar binaries carried
out in February 1986 with the ESO 1.5m-telescope equipped with
the Coudé-spectrograph the Beta Lyrae type object HD72754 = FY
Vel (B2I:pe; 05h29m24s; -49d16'; 1900) was observed twice with
a dispersion of 12A/mm in the spectral range 3650A <= lambda <= 5050A
(baked IIaO-emulsion). The two spectra were obtained at
JD2446467,68 and JD2446468,60 corresponding to orbital
phases = 0.56 (spectrum No. 1) and = 0.59 (spectrum No. 2);
respectively. The reductions were carried out at Astronet pole
in Trieste; Italy; using a PDS microdensitometer and ELSPEC
software package (Pasian, Rusconi and Sedmak; 1982). The RMS
errors resulting from calibration are 2% in exposure and 0.01A
in wavelength values. The wavelengths were reduced to a 
heliocentric scale.
   Both spectra clearly show the Balmer series in absorption from
H8 up to H28; while H_delta, H_gamma, and H_beta display broad emissions
superposed by a central absorption. In addition; the lines H8
up to H28 as well as the HeI=singlet lines lambdalambda 3926, 3965,
4009, 4143, 4388, 4438, 4922, 5016 exhibit red- as well as
blue-shifted satellite lines which are much more pronounced at
orbital phase = 0.56 than at = 0.59; the same is true at
least for CaIIK; while CaIIH is not completely separated from
H_epsilon. In Fig. 1 the profiles of the lines H15, H9 and
HeI(51) lambda4388 taken from spectrum No. 1 are plotted as an
example.

                        [FIGURE 1]

   Especially at orbital phase = 0.56; i.e. close to secondary
minimum; part of the HeI-lines mentioned above seem to display
even more satellite lines (complex multifolded structure of
the profiles); as an example; Fig. 2 shows the region around
HeI(50) lambda4438 for both spectral note that this feature has
considerably changed from = 0.56 to = 0.59; a fact which
was also observed for some other lines.

                        [FIGURE 2]

This satellite line phenomenon seems worth while being compared 
to Beta Lyrae; which is similar to HD72754 in several respects
(Thackeray; 1971); red-shifted satellite lines being observed
shortly before and blue-shifted satellites shortly after primary 
eclipse.
   The mean velocity-displacements of the line systems are given
in Table 1 (no account has been made for the gamma-velocity of the
system).

Table 1: Mean Velocity-Displacements of the Line Systems

Spectrum No. 1:

Blue-shifted satellite line : v = (-67+-17)km/sec
Central component : v = (+7+-5)km/sec
Red-shifted satellite line : v = (+80+-27)km/sec

Spectrum No. 2:

Blue=shifted satellite line : V = (-58+-11)km/sec
Central component : v = (+22+-6)km/sec
Red-shifted component : v = (+121+-20)km/sec

   The mean velocity of the central component increasing from
orbital phase = 0.56 to = 0.59 is well in agreement with
attributing this component (also being the strongest) to the
primary.
   The satellite lines then might be due to gaseous streams moving 
from one component to the following side of the other one.
It should be mentioned that at least part of the central 
absorption components mentioned above appear to be doubled or
even multiple features.
   Other features clearly identified are the HeI-doublet lines
lambdalambda4026, 4421, 4471, 4713 as well as the MgII4481-doublet;
and also some NII- and SiII-lines are seen; they all exhibiting
complex multiple-structure profiles.
   Also two red spectra of HD72754 with a dispersion of 20A/mm
have been obtained; analysis is still in progress, and results
will be published later. High-resolution spectroscopy covering
a whole cycle in well spaced intervals will be necessary to
derive a detailed model of this interesting system.

(This work was partly supported by the Deutsche Forschungsgemeinschaft 
DFG; grant Ra 136/12-2)


WOLFGANG STRUPAT          CONRAD BOEHM
Remeis-Observatory        Osservatorio Astronomico
Bamberg                   di Trieste
Sternwartstrasse 7        Via Tiepolo 11
D-8600 Bamberg / F.R.G.   I-34131 Trieste / Italy



References:

Thackeray, A.D. 1971, Mon. Not. R. Astr. Soc. 154, 103. [BIBCODE 1971MNRAS.154..103T ]
Pasian, F., Rusconi, L., Sedmak, G. 1982, Publ. Oss. Astron. Trieste No. 806.