The mysterious SU UMa stars

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Sky and Telescope; (USA)

OSTI ID:6691049

Charles, P A ^[1]

---

1. Royal Greenwich Observatory, La Palma (Spain)

This paper discusses the characteristics and the source of energy of the explosive stars called cataclysmic variables (CVs), with special attention given to the SU UMa stars, which represent CVs which have disks. In SU UMa binaries, a gas stream from a cool reddish star hits an accretion disk spiraling around a white dwarf. The impact of the stream produces a bright 'hot spot' on the edge of the disk, seen only when the system is quiescent and the disk is relatively dim (during outbursts, the hot spot is swamped by the light of the disk itself). The principal source of energy and light of most CVs is the gravitational potential energy released by matter falling from the dim reddish companion onto the white dwarf. The mechanism involved in the overflow of the reddish star is believed to be magnetic braking. Simulations are presented that explain the SU UMa phenomena and which may be applicable to other high-mass-ratio interacting binaries.

• OSTI ID: 6691049
• Journal Information: Sky and Telescope; (USA), Journal Name: Sky and Telescope; (USA) Vol. 79; ISSN SKTEA; ISSN 0037-6604
• 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
ACCRETION DISKS
BINARY STARS
DWARF STARS
ENERGY
ENERGY SOURCES
ERUPTIVE VARIABLE STARS
GRAVITATIONAL FIELDS
LIGHT SOURCES
MAIN SEQUENCE STARS
NOVAE
POTENTIAL ENERGY
RADIATION SOURCES
STARS
VARIABLE STARS
WHITE DWARF STARS