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Oscillations of red dwarfs in evolved low-mass binaries with neutron starsWe investigate a novel aspect of a problem related to the properties of low-mass binaries (LMBs) with millisecond pulsars: the pulsations of the red dwarf (donor) companion of the neutron star (NS). The illumination of the donor star by the pulsar's high-energy nonthermal radiation and relativistic wind may substantially affect its structure. We present a quantitative analysis of the oscillation spectrum of a red dwarf which has evolved in an LMB and has undergone the stage of evaporation. We calculate the p- and g-modes for red dwarfs with masses in the interval (0.2-0.6) stellar mass. For comparison, similar calculations are presented for zero age main-sequence (ZAMS) stars of the same masses. For less massive donor stars (approximately 0.2 stellar mass) the oscillation spectrum becomes quantitatively different from that of their ZAMS counterparts. The differnce is due to the fact that a ZAMS star of 0.2 stellar mass is fully convective, while the donor star in an LMB is expected to be far from thermal equilibrium and not fully convective. As a result, in contrast to a low-mass ZAMS star, a red dwarf of the same mass in an LMB allows the existence of g-modes. We also consider tidally forced g-modes, and perform a linear analysis of these oscillations for different degrees of nonsynchronism between the orbital and spin rotation of the red dwarf component. We demonstrate the existence of a series of reasonances for the low-order g-modes which may occur in LMBs at a late stage of their evolution. We discuss the possibility that these oscillations may trigger Roche lobe overflow and sudden mass loss by the donor star. Further implications of this effect for gamma- and X-ray burst phenomena are outlined.
Document ID
19950030868
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Sarna, Marek J.
(Polish Academy of Sciences Warsaw, Poland)
Lee, Umin
(Ecole Normale Superieure de Lyon Lyon, France)
Muslimov, Alexander G.
(Univ. of Rochester, Rochester, NY United States)
Date Acquired
August 16, 2013
Publication Date
August 10, 1994
Publication Information
Publication: The Astrophysical Journal, Part 1
Volume: 431
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A62467
Funding Number(s)
CONTRACT_GRANT: NAGW-2444
CONTRACT_GRANT: NSF AST-91-15132
Distribution Limits
Public
Copyright
Other

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