IN-SYNC. V. Stellar Kinematics and Dynamics in the Orion A Molecular Cloud
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Author
Da Rio, NicolaTan, Jonathan C.

Covey, Kevin R.

Cottaar, Michiel

Foster, Jonathan B.

Cullen, Nicholas C.
Tobin, John

Kim, Jinyoung Serena

Meyer, Michael R.

Nidever, David L.

Stassun, Keivan G.

Chojnowski, S. Drew

Flaherty, Kevin M.

Majewski, Steven R.

Skrutskie, Michael F.
Zasowski, Gail
Pan, Kaike
Affiliation
Univ Arizona, Steward ObservIssue Date
2017-08-16Keywords
open clusters and associations: individual (Orion Nebula Cluster, L1641)stars: formation
stars: kinematics and dynamics
stars: pre-main sequence
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IOP PUBLISHING LTDCitation
IN-SYNC. V. Stellar Kinematics and Dynamics in the Orion A Molecular Cloud 2017, 845 (2):105 The Astrophysical JournalJournal
The Astrophysical JournalRights
© 2017. The American Astronomical Society. All rights reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
The kinematics and dynamics of young stellar populations enable us to test theories of star formation. With this aim, we continue our analysis of the SDSS-III/APOGEE IN-SYNC survey, a high-resolution near-infrared spectroscopic survey of young clusters. We focus on the Orion A star-forming region, for which IN-SYNC obtained spectra of similar to 2700 stars. In Paper IV we used these data to study the young stellar population. Here we study the kinematic properties through radial velocities (vr). The young stellar population remains kinematically associated with the molecular gas, following a similar to 10 km s(-1) gradient along the filament. However, near the center of the region, the vr distribution is slightly blueshifted and asymmetric; we suggest that this population, which is older, is slightly in the foreground. We find evidence for kinematic subclustering, detecting statistically significant groupings of colocated stars with coherent motions. These are mostly in the lower-density regions of the cloud, while the ONC radial velocities are smoothly distributed, consistent with it being an older, more dynamically evolved cluster. The velocity dispersion sigma(v) varies along the filament. The ONC appears virialized, or just slightly supervirial, consistent with an old dynamical age. Here there is also some evidence for ongoing expansion, from a v(r)-extinction correlation. In the southern filament, sigma(v) is similar to 2-3 times larger than virial in the L1641N region, where we infer a superposition along the line of sight of stellar subpopulations, detached from the gas. In contrast, sv decreases toward L1641S, where the population is again in agreement with a virial state.ISSN
1538-4357Version
Final published versionSponsors
University of Oklahoma; Homer L. Dodge endowed chair; Netherlands Organisation for Scientific Research (NWO) [639.041.439]Additional Links
http://stacks.iop.org/0004-637X/845/i=2/a=105?key=crossref.4c39b43cf56b43d7314ea5021bffa570ae974a485f413a2113503eed53cd6c53
10.3847/1538-4357/aa7a5b