The origin of MHD jets in T Tauri stars

• Tipo: Artigo em Livro de Atas de Conferência Internacional
• Data: 2005

Autores

P. Garcia (Autor) FEUP

Ata de Conferência Internacional

Título: MAGNETIC FIELDS IN THE UNIVERSE: FROM LABORATORY AND STARS TO PRIMORDIAL STRUCTURES

Páginas: 215-225

Conference on Magnetic Fields in the Universe - From Laboratory and Stars to Primordial Structures

Angra dos Reis, BRAZIL, NOV 28-DEC 03, 2004

Indexação

ISI Proceedings

ISI Web of Knowledge - 0 Citações

Scopus - 0 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Física

Outras Informações

ID Authenticus: P-000-66Z

DOI: 10.1063/1.2077186

Abstract (EN): In this contribution, we consider stationary MHD ejection models from the disk surface, the star-disk corotation region ("X-wind"), and the star itself We compare their predicted angular momentum and poloidal speeds with recent observations of T Tauri jet kinematics, and review the resulting constraints on the launch radius, magnetic lever-arm, and heat deposition in the jet (see Ferreira et al. 2005 for more details). Cold MHD disk winds are found to predict excessive rotation in T Tauri jets and are definitely excluded, while warm MHD disk winds (including heating at the disk surface) with moderate magnetic lever arms lambda = (r(A)/r(0))(2) similar or equal to 6 - 20 reproduce very well both the observed rotation signatures and poloidal speeds, if launching radii extend to r(0) similar or equal to 0.1-3 AU. Both stellar winds and X-winds are challenged by the range of poloidal speeds in T Tauri jets: It should be checked if stellar winds can accelerate the observed jet mass-flux without excessive radiative losses, and if X-winds can sweep-up enough ambient gas to explain the intermediate-velocity components towards jet edges. We also show that, contrary to common belief, warm self-similar disk winds are capable of reproducing the collimation, line profiles, and ejection/accretion ratio in T Tauri jets. Implications of the steady warm disk-wind hypothesis on physical conditions in T Tauri disks (e.g. the required magnetic flux) are recalled.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 11