COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1147

                               Konkoly Observatory
                               Budapest
                               1976 June 29



         Halpha EMISSION IN THE ECLIPSING WHITE
               DWARF V471 Tau (BD+16d516)



  Spectroscopic observations of the eclipsing white dwarf
V471 Tauri (BD+16d516) were obtained at the coude focus of the
Mt. Wilson 2.5 meter telescope during the 1975-76 season. The
exposures were taken on IIa-D emulsion plates with the 81 cm
camera in combination with an S25 cathode Varo image tube at
a dispersion of 6.5 Angstrom/mm.
  Halpha emission was detected on the plate obtained JD 2442702.89.
The phase of the binary orbit at mid exposure was ~ 0.524, following 
the elements of Young and Lanning (1975). The two hour
exposure is weak and the Halpha feature broadened by orbital motion
(Period ~ 12.5 hours) making a study of the line impractical. An
additional plate on JD 2442800.71, phase ~ 0.212, showed marginal
evidence of Halpha in emission.
  Cester and Pucillo (1976) have suggested the presence of
circumstellar matter around V471 Tau from a study of the photometric 
variability of the binary. Photometric observations by
one of us (HHL) confirm those obtained by Cester and Pucillo.
These data, together with the detection of Halpha emission presented
here, and the period variations noted by Young and Lanning, may
add support to their hypothesis. Photometric variations on time
scales of 30-60 days have been observed by HHL suggesting the
occurrence of chromospheric activity, and may indicate the source
of the Halpha emission. Emission of singly ionized Calcium presumed
to result from a transient event has also been observed by Young
and Nelson (1972). Unfortunately, no simultaneous photometric
and spectroscopic observations have succesfully been obtained
during any of these events.
  Coordinated spectroscopic (CaII and Halpha) and photometric 
observations are clearly needed to determine the nature of the 
observed emission and photometric variability.

  We wish to thank Dr. Horace Babcock, Director of Hale Observatories, 
for the allocation of observing time on the 2.5 meter
telescope of the Mt. Wilson Observatory.





                       HOWARD H. LANNING
                  Hale Observatories, Carnegie
                    Institution of Washington
                 California Institute of Technology



                         and



                         PAUL B. ETZEL
                    San Diego State University,
                    Astronomy Department




References:
Young, A. and Nelson, B. 1972, Ap.J. 173, 653 [BIBCODE 1972ApJ...173..653Y ]
Young, A. and Lanning, H. 1975, PASP 87, 461 [BIBCODE 1975PASP...87..461Y ]
Cester, B. and Pucillo, M. 1976, Astron.and Astrophys. 46, 197 [BIBCODE 1976A&A....46..197C ]