| | |
| | |
Stat |
Members: 3643 Articles: 2'487'895 Articles rated: 2609
28 March 2024 |
|
| | | |
|
Article overview
| |
|
IN-SYNC. V. Stellar kinematics and dynamics in the Orion A Molecular Cloud | Nicola Da Rio
; Jonathan C. Tan
; Kevin R. Covey
; Michiel Cottaar
; Jonathan B. Foster
; Nicholas C. Cullen
; John J. Tobin
; Jinyoung S. Kim
; Michael R. Meyer
; David L. Nidever
; Keivan G. Stassun
; S. Drew Chojnowski
; Kevin M. Flaherty
; Steve Majewski
; Michael F. Skrutskie
; Gail Zasowski
; Kaike Pan
; | Date: |
14 Feb 2017 | Abstract: | The kinematics and dynamics of young stellar populations tests theories of
their formation. With this aim, we continue our analysis of the SDSS-III/APOGEE
INfrared Spectra of Young Nebulous Clusters (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 ~2700 stars. In
Paper IV we used these data to study the young stellar population, through
measurement of stellar parameters to study age spread and assign new
memberships. Here we study the kinematic properties through radial velocities
($v_r$). The young stellar population remains kinematically associated with the
molecular gas, following a ~10km/s $v_r$ gradient along the 40pc long filament.
However, near the center of the region stars appear ~1km/s blue-shifted with
respect to the gas and show an asymmetric $v_r$ distribution. This region is
slightly older and less embedded than average, suggesting that the remaining
gas is mostly behind the population along the line of sight. We find evidence
for kinematic subclustering, detecting statistically significant groupings of
co-located stars with coherent motions. These are mostly in the lower-density,
dispersed filament south of the ONC, which, on the other hand, appears
dynamically evolved. The 1-D velocity dispersion is roughly constant throughout
the region (2-2.5km/s). The ONC has a virial parameter $alpha$~1.8, i.e., near
the limit for the cluster to remain bound. In the ONC we also find some
evidence for on-going expansion, from a correlation between $v_r$ and
extinction. In the lower-density region south of the ONC, the velocity
dispersion is ~3 times larger than expected from virial equilibrium, i.e.,
unbound. The origin of these high stellar velocities remains somewhat unclear,
especially since the velocity dispersion of the gas is consistent a virial
state. | Source: | arXiv, 1702.4113 | Services: | Forum | Review | PDF | Favorites |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser claudebot
|
| |
|
|
|
| News, job offers and information for researchers and scientists:
| |