Nonradial and nonpolytropic astrophysical outflows. IX. Modeling T Tauri jets with a low mass-accretion rate - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2011

Nonradial and nonpolytropic astrophysical outflows. IX. Modeling T Tauri jets with a low mass-accretion rate

Résumé

Context. A large sample of T Tauri stars exhibits optical jets, approximately half of which rotate slowly, only at ten per cent of their breakup velocity. The disk-locking mechanism has been shown to be inefficient to explain this observational fact.
Aims: We show that low mass accreting T Tauri stars may have a strong stellar jet component that can effectively brake the star to the observed rotation speed.
Methods: By means of a nonlinear separation of the variables in the full set of the MHD equations we construct semi-analytical solutions describing the dynamics and topology of the stellar component of the jet that emerges from the corona of the star.
Results: We analyze two typical solutions with the same mass loss rate but different magnetic lever arms and jet radii. The first solution with a long lever arm and a wide jet radius effectively brakes the star and can be applied to the visible jets of T Tauri stars such as RY Tau. The second solution with a shorter lever arm and a very narrow jet radius may explain why similar stars, either weak line T Tauri stars (WTTS) or classical T Tauri stars (CTTS) do not all have visible jets. For instance, RY Tau itself seems to have different phases that probably depend on the activity of the star.
Conclusions: First, stellar jets seem to be able to brake pre-main sequence stars with a low mass accreting rate. Second, jets may be visible only part time owing to changes in their boundary conditions. We also suggest a possible scenario for explaining the dichotomy between CTTS and WTTS, which rotate faster and do not have visible jets.

Dates et versions

hal-03730865 , version 1 (20-07-2022)

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Christophe Sauty, Zakaria Meliani, J. J. G. Lima, K. Tsinganos, Véronique Cayatte, et al.. Nonradial and nonpolytropic astrophysical outflows. IX. Modeling T Tauri jets with a low mass-accretion rate. Astronomy and Astrophysics - A&A, 2011, 533, pp.46. ⟨10.1051/0004-6361/201116519⟩. ⟨hal-03730865⟩
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