The origin of MHD jets in T Tauri stars

• Type: Article in International Conference Proceedings Book
• Date: 2005

Authors

P. Garcia (Author) FEUP

Conference proceedings International

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

Pages: 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

Indexing

ISI Proceedings

ISI Web of Knowledge - 0 Citations

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Scientific classification

FOS: Natural sciences > Physical sciences

Other information

Authenticus ID: 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11