X-rays from spherical accretion onto degenerate dwarfs

Journal Article · Fri Jul 01 04:00:00 EDT 1977 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/155355· OSTI ID:7319433

Katz, J I

I reconsider spherically symmetric accretion onto degenerate dwarfs. The problem is divided into three parameter regimes on the basis of the accretion rate. In the regime of highest accretion rates, the flow is optically thick. For the middle regime, previous calculations by Aizu are extended to include Compton cooling of the shocked material by thermal radiation from the photosphere. If the accreted material is hydrogen-rich and burns, this effect greatly reduces the efficiency of X-ray production. In the lowest regime of accretion rate, the shock occurs far from the star, and the accretional energy is radiated through a thick layer. Graphs of the radiation spectrum and other quantities of interest are presented. Accreting degenerate dwarfs are expected to be characterized by very hard X-ray spectra, which are nearly independent of other variations in the properties of the source. Applications of these results include arguments against the degenerate dwarf hypothesis for Sco X-1 and 3U 0900--40, and suggested observations of DQ Her.

• Research Organization: Institute for Advanced Study, Princeton
• OSTI ID: 7319433
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 215:1; ISSN ASJOA
• 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
ATMOSPHERES
BASIC INTERACTIONS
BINARY STARS
BREMSSTRAHLUNG
COMPTON EFFECT
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
DWARF STARS
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
FLUID MECHANICS
HYDRODYNAMICS
INTERACTIONS
IONIZING RADIATIONS
MAGNETIC FIELDS
MECHANICS
RADIATIONS
SCATTERING
SPECTRA
STAR ACCRETION
STAR EVOLUTION
STARS
STELLAR ATMOSPHERES
WHITE DWARF STARS
X RADIATION
X-RAY SPECTRA