Disk accretion onto magnetic T Tauri stars

Journal Article · Fri Mar 01 04:00:00 EST 1991 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/185972· OSTI ID:5867781

Koenigl, A ^[1]

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1. Chicago Univ., IL (USA)

The dynamical and radiative consequences of disk accretion onto magnetic T Tauri stars (TTS) are examined using the Ghosh and Lamb model. It is shown that a prolonged disk accretion phase is compatible with the low rotation rates measured in these stars if they possess a kilogauss strength field that disrupts the disk at a distance of a few stellar radii from the center. It is estimated that a steady state in which the net torque exerted on the star is zero can be attained on a time scale that is shorter than the age of the youngest visible TTS. Although the disk does not develop an ordinary shear boundary layer in this case, one can account for the observed UV excess and Balmer emission in terms of the shocks that form at the bottom of the high-latitude magnetic accretion columns on the stellar surface. This picture also provides a natural explanation of some of the puzzling variability properties of stars like DF Tau and RY Lup. YY Ori stars are interpreted as magnetic TTS in which the observer's line of sight is roughly parallel to an accretion column. 37 refs.

• OSTI ID: 5867781
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 370; ISSN ASJOA; ISSN 0004-637X
• 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
ASTROPHYSICS
BOUNDARY LAYERS
ELECTROMAGNETIC RADIATION
ERUPTIVE VARIABLE STARS
LAYERS
MAGNETIC FIELDS
MAGNETIC STARS
MATHEMATICAL MODELS
RADIATIONS
STAR ACCRETION
STAR EVOLUTION
STAR MODELS
STARS
T TAURI STARS
ULTRAVIOLET RADIATION
VARIABLE STARS
VARIATIONS