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EUVE and VLA Observations of the Eclipsing Pre-Cataclysmic Variable V471 Tauri

Published online by Cambridge University Press:  12 April 2016

S.L. Cully ,
J. Dupuis ,
T. Rodriguez-Bell ,
G. Basri ,
O.H.W. Siegmund ,
J. Lim  and
S.M. White
S.L. Cully
Affiliation:
Experimental Astrophysics Group, Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450USA Center for Extreme Ultraviolet Astrophysics, 2150 Kittredge Street, University of California, Berkeley, CA 94720-5030USA
J. Dupuis
Affiliation:
Center for Extreme Ultraviolet Astrophysics, 2150 Kittredge Street, University of California, Berkeley, CA 94720-5030USA
T. Rodriguez-Bell
Affiliation:
Experimental Astrophysics Group, Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450USA
G. Basri
Affiliation:
Department of Astronomy, University of California Berkeley, CA 94720-3411USA
O.H.W. Siegmund
Affiliation:
Experimental Astrophysics Group, Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450USA Center for Extreme Ultraviolet Astrophysics, 2150 Kittredge Street, University of California, Berkeley, CA 94720-5030USA
J. Lim
Affiliation:
Institute of Astronomy and Astrophysics, Academia Sinica PO Box 1-87, Nankang, Taipei, Taiwan 115, ROC
S.M. White
Affiliation:
Department of Astronomy, University of Maryland College Park, MD 20742USA

Abstract

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We present observations of the eclipsing binary V471 Tauri by the Extreme Ultraviolet Explorer (EUVE) and the Very Large Array (VLA). The EUV spectrum is dominated by the continuum of the hot white dwarf and the time-averaged spectrum is fitted by a 33.1 ± 0.5 × 103 K pure hydrogen white dwarf atmosphere assuming log g = 8.5. An ISM hydrogen column density of 1.5 ± 0.4 × 1018 cm−2 is required to explain the attenuation of the white dwarf spectrum thus setting the HI column in the line of sight of the Hyades cluster. The He II λ304 Å line is in emission and varies over the orbital period of V471 Tauri following a sinusoidal modulation with the maximum reached when the K star is at inferior conjunction. Transient dips are detected at orbital phase −0.12 in the SW and MW spectrometers integrated lightcurves but are notably absent in the LW lightcurve indicating the occulting material is ionized. The VLA observation suggest the presence of a K star coronal magnetic loop between the two stars reconnecting with the white dwarf magnetic field. Such a structure could be the occulting source needed to explain the dips seen in the lightcurves of V471 Tauri in the EUV.

Type
VI. Cataclysmic Variable Stars
Information
International Astronomical Union Colloquium , Volume 152: Astrophysics in the Extreme Ultraviolet , 1996 , pp. 349 - 354
Copyright
Copyright © Kluwer 1996

References

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