SIMBAD references

2018ApJ...868...28F - Astrophys. J., 868, 28-28 (2018/November-3)

A new look at T Tauri star forbidden lines: MHD-driven winds from the inner disk.

FANG M., PASCUCCI I., EDWARDS S., GORTI U., BANZATTI A., FLOCK M., HARTIGAN P., HERCZEG G.J. and DUPREE A.K.

Abstract (from CDS):

Magnetohydrodynamic (MHD) and photoevaporative winds are thought to play an important role in the evolution and dispersal of planet-forming disks. We report the first high-resolution (Δv ∼ 6 km s–1) analysis of [S II] λ4068, [O I] λ5577, and [O I] λ6300 lines from a sample of 48 T Tauri stars. Following Simon et al. we decompose them into three kinematic components: a high-velocity component (HVC) associated with jets, and low-velocity narrow (LVC-NC) and broad (LVC-BC) components. We confirm previous findings that many LVCs are blueshifted by more than 1.5 km s–1 and thus most likely trace a slow disk wind. We further show that the profiles of individual components are similar in the three lines. We find that most LVC-NC and LVC-BC line ratios are explained by thermally excited gas with temperatures between 5000 and 10,000 K and electron densities of ∼107-108 cm–3. The HVC ratios are better reproduced by shock models with a pre-shock H number density of ∼106-107 cm–3. Using these physical properties, we estimate {dot}Mwind/{dot}Macc for the LVC and {dot}Mjet/{dot}Macc for the HVC. In agreement with previous work, the mass carried out in jets is modest compared to the accretion rate. With the likely assumption that the LVC-NC wind height is larger than the LVC-BC, the LVC-BC {dot}Mwind/{dot}Macc is found to be higher than the LVC-NC. These results suggest that most of the mass loss occurs close to the central star, within a few au, through an MHD-driven wind. Depending on the wind height, MHD winds might play a major role in the evolution of the disk mass.

Abstract Copyright: © 2018. The American Astronomical Society. All rights reserved.

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

CDS comments: Table 1: KW27 and KW 541 were not identified.

Simbad objects: 74

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2020.01.20-10:31:33

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