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Wave energy in white dwarf atmospheres. I - Magnetohydrodynamic energy spectra for homogeneous DB and layered DA starsThe radiative damping of acoustic and MHD waves that propagate through white dwarf photospheric layers is studied, and other damping processes that may be important for the propagation of the MHD waves are calculated. The amount of energy remaining after the damping processes have occurred in different types of waves is estimated. The results show that lower acoustic fluxes should be expected in layered DA and homogeneous DB white dwarfs than had previously been estimated. Acoustic emission manifests itself in an enhancement of the quadrupole term, but this term may become comparable to or even lower than the dipole term for cool white dwarfs. Energy carried by the acoustic waves is significantly dissipated in deep photospheric layers, mainly because of radiative damping. Acoustically heated corona cannot exist around DA and DB white dwarfs in a range T(eff) = 10,000-30,000 K and for log g = 7 and 8. However, relatively hot and massive white dwarfs could be exceptions.
Document ID
19880034195
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Musielak, Zdzislaw E.
(NASA Marshall Space Flight Center Huntsville, AL; MIT, Cambridge, MA, United States)
Date Acquired
August 13, 2013
Publication Date
November 1, 1987
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 322
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
88A21422
Funding Number(s)
CONTRACT_GRANT: NGL-22-009-015
Distribution Limits
Public
Copyright
Other

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