A VLBA Survey of radio stars in the Orion Nebula Cluster: II. Astrometry

Abstract

From Very Long Baseline Array (VLBA) observations we previously identified a population of 123 young stellar systems with nonthermal radio emission toward the core of the Orion Nebula Cluster (ONC). We find optical sources in the Gaia DR2 catalog for 34 of them within 0.2" of the radio positions. Most of the radio sources are likely companions of Gaia detections. However, there are 11 stars whose VLBA position differs from Gaia by $<1.6$ mas, and some of these radio sources probably are the direct counterparts of the optical stars. We are able to obtain radio proper motions for 23 stars. Combining the stellar proper motions derived from the VLBA and Gaia data we find the global motion and velocity dispersion of the ONC to be (${\mu }_{\alpha }\ast ,{\mu }_{\delta }$)=($1.20\pm 0.09,0.18\pm 0.09$) mas yr${}^{-1}$ and (${\sigma }_{{\mu }_{\alpha }\ast },{\sigma }_{{\mu }_{\delta }}$)=($0.84\pm 0.09,1.30\pm 0.09$) mas yr${}^{-1}$. Finally, we looked for ordered motions by estimating the means of scalar and vectorial products, which results in $\overline{\mathbf{v}\cdot \hat{\mathbf{r}}}=-0.61\pm 1.00$ km s${}^{-1}$ and $\overline{\mathbf{v}\times \hat{\mathbf{r}}}=0.57\pm 0.95$ km s${}^{-1}$. These do not show indications that the young stellar cluster is in expansion, contraction, or rotation.

arXiv commentAccepted for publication in ApJ. 16 pages, 4 figures, 7 tables

References in corpus (35)

• Gaia Data Release 2. Summary of the contents and survey properties
• The distance to the Orion Nebula
• DiFX2: A more flexible, efficient, robust and powerful software correlator
• Kinematics in Young Star Clusters and Associations with Gaia DR2
• Stellar Radio Astronomy. Probing Stellar Atmospheres from Protostars to Giants
• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• Micro-Arcsecond Radio Astrometry
• Distance to Orion KL Measured with VERA
• The Initial Mass Function of the Orion Nebula Cluster across the H-burning limit
• Membership of the Orion Nebula Population from the Chandra Orion Ultradeep Project
• A Parallactic Distance of 389 +24/-21 parsecs to the Orion Nebula Cluster from Very Long Baseline Array Observations
• Monitoring the Large Proper Motions of Radio Sources in the Orion BN/KL Region
• Dynamical decay of a massive multiple system in Orion KL?
• Fundamental properties of nearby single early B-type stars
• VISION - Vienna survey in Orion I. VISTA Orion A Survey
• Compact Radio Sources in Orion: New Detections, Time Variability, and Objects in OMC-1S
• A quantitative analysis of systematic differences in positions and proper motions of Gaia DR2 with respect to VLBI
• On significance of VLBI/Gaia position offsets
• An Enhanced Spectroscopic Census of the Orion Nebula Cluster
• Interacting coronae of two T Tauri stars: first observational evidence for solar-like helmet streamers
• Comparison of Gaia DR2 Parallaxes of Stars with VLBI Astrometry
• Is stellar multiplicity universal? Tight stellar binaries in the Orion Nebula Cluster
• Radio Measurements of the stellar proper motions in the core of the Orion Nebula Cluster
• The Population of Compact Radio Sources in the Orion Nebula Cluster
• The Gould's Belt Very Large Array Survey III. The Orion region
• Multiple Star Systems in the Orion Nebula
• Stellar Proper Motions in the Orion Nebula Cluster
• A 1.3 cm wavelength radio flare from a deeply embedded source in the Orion BN/KL region
• The Proper Motions of the Double Radio Source n in the Orion BN/KL Region
• Internal and relative motions of the Taurus and Ophiuchus star-forming regions
• Techniques for Accurate Parallax Measurements for 6.7-GHz Methanol Masers
• The multiplicity of massive stars in the Orion Nebula cluster as seen with long-baseline interferometry
• A VLBA Survey of radio stars in the Orion Nebula Cluster: I. The nonthermal radio population
• HST astrometry in the Orion Nebula Cluster: census of low-mass runaways
• Proper Motions of the Radio Source Orion MR, Formerly Known as Orion n, and New Sources with Large Proper Motions in Orion BN/KL

Cited by in corpus (9)

• A VLBA Survey of radio stars in the Orion Nebula Cluster: I. The nonthermal radio population
• Non-thermal radio continuum emission from young nearby stars
• A systematic survey of millimetre-wavelength flaring variability of Young Stellar Objects in the Orion Nebula Cluster
• From downtown to the outskirts: a radio survey of the Orion Nebula Cluster
• Link between the Optical and Radio Frames from Gaia DR3 Data and VLBI Measurements
• Dynamical masses of YSOs with the VLBA: DYNAMO VLBA: Trigonometric parallaxes and proper motions of YSOs in Orion
• VLBI detection of nearby (< 100 pc) young stars: Pilot observations
• Dynamical masses of young stellar objects with the VLBA: DYNAMO-VLBA: Radio binary stars in Orion
• The population of compact radio sources in M 17