Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· References in the article
· Citations to the Article (173) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (7)
· Associated Articles
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Emission-Line Diagnostics of T Tauri Magnetospheric Accretion. II. Improved Model Tests and Insights into Accretion Physics
Authors:
Muzerolle, James; Calvet, Nuria; Hartmann, Lee
Affiliation:
AA(Harvard-Smithsonian Center for Astrophysics, Mail Stop 42, 60 Garden Street, Cambridge, MA 02138; ; Current address: Steward Observatory, 933 North Cherry Avenue, Tucson, AZ, 85721.), AB(Harvard-Smithsonian Center for Astrophysics, Mail Stop 42, 60 Garden Street, Cambridge, MA 02138; ; Other affiliation: Centro de Investigaciones de Astronomia, Apartado Postal 264, Mérida, 5101-A, Venezuela.), AC(Harvard-Smithsonian Center for Astrophysics, Mail Stop 42, 60 Garden Street, Cambridge, MA 02138; )
Publication:
The Astrophysical Journal, Volume 550, Issue 2, pp. 944-961. (ApJ Homepage)
Publication Date:
04/2001
Origin:
UCP
ApJ Keywords:
Accretion, Accretion Disks, Radiative Transfer, Stars: Formation, Stars: Pre-Main-Sequence
DOI:
10.1086/319779
Bibliographic Code:
2001ApJ...550..944M

Abstract

We present new radiative transfer models of magnetospheric accretion in T Tauri stars. Hydrogen and Na I line profiles were calculated, including line damping and continuum opacity for a grid of models spanning a large range of infall rates, magnetospheric geometries, and gas temperatures. We also calculated models for rotating magnetospheres and show that for typical T Tauri rotation rates, the line profiles are not significantly affected. We show that line-damping wings can produce significant high-velocity emission at Hα, and to a lesser extent in higher Balmer lines, in much better agreement with observations than previous models. We present comparisons to specific objects spanning a wide range of accretion activity and find that in most cases the models successfully reproduce the observed emission profile features. Blueshifted absorption components cannot be explained without including a wind outside of the magnetosphere, and true P Cygni Balmer line profiles in the few objects with extreme accretion activity indicate both absorption and emission from a wind. We constrain the range of gas temperatures required to explain observational diagnostics like profile shapes, line ratios, and continuum emission. The exact heating mechanism remains unclear but is probably linked to the accretion process itself. In order to explain observed correlations between line emission and accretion luminosity, we find that the size of the emitting region must be correlated with the accretion rate. We suggest that such a correlation may manifest itself in reality via nonaxisymmetric accretion, where the number and/or width of discrete funnel flows increase with increasing accretion rate, a scenario also indicated by accretion shock models.

Associated Articles

Part 1     Part  2    

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints