TRACING SLOW WINDS FROM T TAURI STARS VIA LOW-VELOCITY FORBIDDEN LINE EMISSION

Journal Article · Thu Nov 10 00:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/831/2/169· OSTI ID:22667219

Simon, M. N.; Pascucci, I.; Keane, J. T. ^[1]; Edwards, S. ^[2]; Feng, W. ^[3]; Gorti, U.; Hollenbach, D. ^[4]; Rigliaco, E. ^[5]

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1. Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)
2. Five College Astronomy Department, Smith College, Northampton, MA 01063 (United States)
3. School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)
4. SETI Institute, Mountain View, CA 94043 (United States)
5. Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland)

Using Keck/HIRES spectra (Δ v ∼ 7 km s{sup -1}) we analyze forbidden lines of [O i] 6300 Å, [O i] 5577 Å and [S ii] 6731 Å from 33 T Tauri stars covering a range of disk evolutionary stages. After removing a high-velocity component (HVC) associated with microjets, we study the properties of the low-velocity component (LVC). The LVC can be attributed to slow disk winds that could be magnetically (magnetohydrodynamic) or thermally (photoevaporative) driven. Both of these winds play an important role in the evolution and dispersal of protoplanetary material. LVC emission is seen in all 30 stars with detected [O i] but only in two out of eight with detected [S ii], so our analysis is largely based on the properties of the [O i] LVC. The LVC itself is resolved into broad (BC) and narrow (NC) kinematic components. Both components are found over a wide range of accretion rates and their luminosity is correlated with the accretion luminosity, but the NC is proportionately stronger than the BC in transition disks. The full width at half maximum of both the BC and NC correlates with disk inclination, consistent with Keplerian broadening from radii of 0.05 to 0.5 au and 0.5 to 5 au, respectively. The velocity centroids of the BC suggest formation in an MHD disk wind, with the largest blueshifts found in sources with closer to face-on orientations. The velocity centroids of the NC, however, show no dependence on disk inclination. The origin of this component is less clear and the evidence for photoevaporation is not conclusive.

• OSTI ID: 22667219
• Journal Information: Astrophysical Journal, Vol. 831, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCRETION DISKS
EMISSION
INCLINATION
LUMINOSITY
MAGNETOHYDRODYNAMICS
PROTOPLANETS
SPECTRA
STAR EVOLUTION
STELLAR WINDS
T TAURI STARS
VELOCITY