Steven R. Cranmer 2009 ApJ 706 824 doi:10.1088/0004-637X/706/1/824
Steven R. Cranmer
Show affiliationsClassical T Tauri stars are pre-main-sequence objects that undergo simultaneous accretion, wind outflow, and coronal X-ray emission. The impact of plasma on the stellar surface from magnetospheric accretion streams is likely to be a dominant source of energy and momentum in the upper atmospheres of these stars. This paper presents a set of models for the dynamics and heating of three distinct regions on T Tauri stars that are affected by accretion: (1) the shocked plasmas directly beneath the magnetospheric accretion streams, (2) stellar winds that are accelerated along open magnetic flux tubes, and (3) closed magnetic loops that resemble the Sun's coronal active regions. For the loops, a self-consistent model of coronal heating was derived from numerical simulations of solar field-line tangling and turbulent dissipation. Individual models are constructed for the properties of 14 well-observed stars in the Taurus-Auriga star-forming region. Predictions for the wind mass-loss rates are, on average, slightly lower than the observations, which suggests that disk winds or X-winds may also contribute to the measured outflows. For some of the stars, however, the modeled stellar winds do appear to contribute significantly to the measured mass fluxes. Predictions for X-ray luminosities from the shocks and loops are in general agreement with existing observations. The stars with the highest accretion rates tend to have X-ray luminosities dominated by the high-temperature (5-10 MK) loops. The X-ray luminosities for the stars having lower accretion rates are dominated by the cooler accretion shocks.
accretion, accretion disks; stars: coronae; stars: mass loss; stars: pre-main sequence; turbulence; X-rays: stars
Issue 1 (2009 November 20)
Received 2009 August 10, accepted for publication 2009 October 14
Published 2009 November 5
Steven R. Cranmer 2009 ApJ 706 824
M. J. Pivovaroff et al. 2000 ApJ 535 379
Akiji Yamamoto 2008 Sci. Technol. Adv. Mater. 9 013001
Matthew S. Tiscareno and Renu Malhotra 2003 The Astronomical Journal 126 3122
Xinming Liu et al 2009 Phys. Med. Biol. 54 6959
N. Asai et al. 2007 ApJ 663 816
A Botman et al 2006 Nanotechnology 17 3779
Jeffrey S. Bary et al 2009 ApJ 706 L168
E. Egami et al. 2000 ApJ 535 561
L. E. Snyder et al. 2005 ApJ 619 914