COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                      Number 1860

                                    Konkoly Observatory
                                    Budapest
                                    1980 October 27

                                    HU ISSN 0374-0676



      H AND K EMISSIONS IN V 471 TAURI ( BD + 16d516 )



    The white dwarf eclipsing variable V 471 Tauri was discovered 
as a spectroscopic variable by Wilson in 1953. In the intervening 
years the star has been observed by many investigators
mainly photoelectrically and also spectroscopically. The photoelectric 
observations of the star indicate that the light curve
of the star exhibits only primary minima and an advancing migration 
wave through the light curve. It was also reported that the
migrating wave appears to indicate a periodicity of about 1/2
years (Ibanoglu, 1978). Although the star has been continuously
observed at the observatory of Ege University, from 1973 until
the present time, the data concerning photoelectric observations
already published goes until 1978. In the mean time or the source
of the migrating wave and its travel through the light curve, many
suggestions were put forward. One of these suggestions is a spat
model where a spot or spots occur on the surface of the star with
changing their positions similar to the Sun, resulting in the
changing appearance of the light curve. It was also suggested
that probable correlation may exist between simultaneous spectroscopic 
and photoelectric observations such as; intensity of
the Ca II (H and K) lines in emission may vary according to the
position of the migrating wave, or ocurrence of H and K emissions
may be correlated with the maxima or minima position of the wave.
Bearing these facts in mind, the star was spectroscopically observed 
at the Observatory of Asiago in March 1980, with 122 cm
Cassegrain telescope, prism spectrograph and image intensifier
with 42 and 40 A/mm dispersions at 3968 and 3933 A,respectively.
When the light curves so far obtained and published examined and
compared with the spectroscopic observations recently obtained,
some interesting results came out seem to be worthwhile particular
attention. ln the Figures 1 and 2, the intensity of H and K lines

                       [FIGURE 1]
                       [FIGURE 2]
                       [FIGURE 3]
                       [FIGURE 4]

versus orbital phases of the star are presented along with the
absolute wavelength scale, derived from the comparison spectra
and also checked by observing one of the variable stars (HD 178596)
from Wilson (1953). At the orbital phase 0.32 H and K emission
does not exist or it is nearly minimum, where as in all other
orbital phases the Ca II emission exists, If we examine the light
curves and particularly the last one, (Tunca et al.,1979) at
0.32 phase where Ca II emission does not exist or its intensity
is in minimum, the light curve exhibits a maximum. Although spectroscopic 
observations presented here were obtained at the begining 
of March 1980 and time duration difference with the last light
curve is about 1 year, if we consider that the migrating wave
shows periodicity with 180 - 192 days interval (Ibanoglu, 1978)
we may anticipate to see the maximum position again in the vicinity 
of the previous position. Where the maximum peak position
within the light curve corresponds to the observation of the star
surface with no spots and this also corresponds to the non existence 
of the Ca II emission. In Figures 1,2 and 3, the microdensitometer 
scans of rotationally broadened H and K emissions within
the absorption lines for different orbital phases are presented.
In Figure 4 the same scans together with the scan of the comparison 
star are presented.
Acknowledgements
I am grateful to Prof.L.Rosino, Director of the observatory of
Asiago for the excellent facilities provided, to Prof.A.Mammano
for constant comments and guidance of the subject and Dr.C.Ibanoglu
and his colleagues for constructive discussions.




                           ESAT HAMZAOGLU

                    The Astrophysical Observatory of
                             Asiago *

References:
Cester, B. and Pucillo,M.,1976, Astron.Astrophys. 46, 197 [BIBCODE 1976A&A....46..197C ]
Ibanoglu, C., 1978,Astrophys.Space Sci. 57, 219 [BIBCODE 1978Ap&SS..57..219I ]
Nelson, B. and Young,A.1970,Publ.Astron.Soc.Pacific 82, 699 [BIBCODE 1970PASP...82..699N ]
Young,A. and Lanning, H.H. 1975,Publ.Astron. Soc.Pacific 87, 461 [BIBCODE 1975PASP...87..461Y ]
Tunca, Z. et al. 1979, Astrophys. Space Sci. 64, 421 [BIBCODE 1979Ap&SS..64..421T ]


* On leave from the Ege University Observatory Present address: Ege Univesity 
 Observatory, P.K. 21, Izmir-Turkey