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Radio Measurements of the Stellar Proper Motions in the Core of the Orion Nebula Cluster
- Source :
- ASTROPHYSICAL JOURNAL (ISSN 0004-637X), 834, 139
- Publication Year :
- 2017
-
Abstract
- Using multi-epoch VLA observations, covering a time baseline of 29.1 years, we have measured the proper motions of 88 young stars with compact radio emission in the core of the Orion Nebula Cluster (ONC) and the neighboring BN/KL region. Our work increases the number of young stars with measured proper motion at radio frequencies by a factor of 2.5 and enables us to perform a better statistical analysis of the kinematics of the region than was previously possible. Most stars (79 out of 88) have proper motions consistent with a Gaussian distribution centered on $\overline{\mu_{\alpha}\cos{\delta}}=1.07\pm0.09\quad{\rm mas\,yr^{-1}}$, and $\overline{\mu_{\delta}}=-0.84\pm0.16\quad{\rm mas\,yr^{-1}}$, with velocity dispersions of $\sigma_{\alpha}=1.08\pm0.07\quad{\rm mas\,\,yr^{-1}},$ $\sigma_{\delta}=1.27\pm0.15\quad{\rm mas\,\,yr^{-1}}$. We looked for organized movements of these stars but found no clear indication of radial expansion/contraction or rotation. The remaining nine stars in our sample show peculiar proper motions that differ from the mean proper motions of the ONC by more than 3-$\sigma$. One of these stars, V 1326 Ori, could have been expelled from the Orion Trapezium 7,000 years ago. Two could be related to the multi-stellar disintegration in the BN/KL region, in addition to the previously known sources BN, I and n. The others either have high uncertainties (so their anomalous proper motions are not firmly established) or could be foreground objects.<br />Comment: 15 pages, 5 figures, 2 tables, 1 appendix, accepted in The Astrophysical Journal
- Subjects :
- Physics
Proper motion
010504 meteorology & atmospheric sciences
Sigma
FOS: Physical sciences
Astronomy and Astrophysics
Astrophysics
Rotation
01 natural sciences
Astrophysics - Astrophysics of Galaxies
Core (optical fiber)
Stars
Distribution (mathematics)
Astrophysics - Solar and Stellar Astrophysics
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
0103 physical sciences
Orion Nebula
Cluster (physics)
010303 astronomy & astrophysics
Solar and Stellar Astrophysics (astro-ph.SR)
0105 earth and related environmental sciences
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- ASTROPHYSICAL JOURNAL (ISSN 0004-637X), 834, 139
- Accession number :
- edsair.doi.dedup.....199c88d61fcb4640c012f4d8e5547589