Time-dependent accretion onto magnetic white dwarfs: Effects of cyclotron emission

Journal Article · Sun Dec 15 04:00:00 EST 1985 · Astrophys. J., Lett. Ed.; (United States)

DOI:https://doi.org/10.1086/184586· OSTI ID:6282534

Chanmugam, G; Langer, S H; Shaviv, G

Previous accretion models have shown that if the cooling is due to optically thin bremsstrahlung, the flow is unstable. The shock height oscillates with a period approx.1 s, which corresponds to the cooling time for parameters characteristic of the AM Her binaries. Here we show that the effects of cyclotron cooling stabilize the flow if the magnetic field is large enough. For a 0.5 M/sub sun/ white dwarf accreting 1 g cm S s , the flow is stable if B is more than or approximately equal to 2 x 10X gauss. We also show that the bremsstrahlung X-ray emission and the optical cyclotron emission are 180 out of phase when oscillations are present. The relevance of these calculations to the observed optical oscillations, with periods of approx.1 s, in two AM Her stars is discussed.

• Research Organization: Department of Physics and Astronomy, Louisiana State University
• OSTI ID: 6282534
• Journal Information: Astrophys. J., Lett. Ed.; (United States), Journal Name: Astrophys. J., Lett. Ed.; (United States) Vol. 299:2; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BINARY STARS
BREMSSTRAHLUNG
CYCLOTRON RADIATION
DATA
DWARF STARS
ELECTROMAGNETIC RADIATION
FLUID MECHANICS
HARD X RADIATION
HYDRODYNAMICS
INFORMATION
IONIZING RADIATIONS
MAGNETIC STARS
MECHANICS
NUMERICAL DATA
OSCILLATIONS
RADIATIONS
SHOCK WAVES
STAR ACCRETION
STAR EVOLUTION
STARS
THEORETICAL DATA
TIME DEPENDENCE
WHITE DWARF STARS
X RADIATION