Query : 2006A&A...453..785F

2006A&A...453..785F - Astronomy and Astrophysics, volume 453, 785-796 (2006/7-3)

Which jet launching mechanism(s) in T Tauri stars?


Abstract (from CDS):

We examine whether ejection phenomena from accreting T Tauri stars can be described by only one type of self-collimated jet model. We present analytical kinematic predictions valid soon after the Alfven surface for all types of steady magnetically self-confined jets. We show that extended disc winds, X-winds, and stellar winds occupy distinct regions in the poloidal speed vs. specific angular momentum plane. Comparisons with current observations of T Tauri jets yield quantitative constraints on the range of launching radii, magnetic lever arms, and specific energy input in disc and stellar winds. Implications on the origin of jet asymmetries and disc magnetic fields are outlined. We argue that ejection phenomena from accreting T Tauri stars most likely include three dynamical components: (1) an outer self-collimated steady disc wind carrying most of the mass-flux in the optical jet (when present); confining (2) a pressure-driven coronal stellar wind; and (3) a hot inner flow made of blobs sporadically ejected from the magnetopause. If the stellar magnetic moment is parallel to the disc magnetic field, then the highly variable inner flow resembles a ``Reconnection X-wind'', that has been proven to efficiently brake down an accreting and contracting young star. If the magnetic moment is anti-parallel, then larger versions of the solar coronal mass ejections are likely to occur. The relative importance of these three components in the observed outflows and the range of radii involved in the disc wind are expected to vary with time, from the stage of embedded source to the optically revealed T Tauri star phase.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - magnetohydrodynamics (MHD) - stars: pre-main sequence - ISM: jets and outflows

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 V* DG Tau Or* 04 27 04.6921275888 +26 06 16.060169268 13.57 13.97 10.50 12.28   K6Ve 1010 1
2 V* RW Aur TT* 05 07 49.5662483 +30 24 05.177426   10.86 9.60 9.95   K1/5e+K5e 772 0
3 HH 212 HH 05 43 51.41 -01 02 53.1           ~ 369 1
4 WRAY 16-203 Or* 16 08 29.7275063376 -39 03 11.024360496   16.26 15.91 15.38 15.69 K0: 166 1
5 EM* LkHA 321 Or* 21 01 55.0706162280 +49 51 36.270580320   13.58 12.34 12.01   ~ 54 0

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