论文标题
VLBA对猎户座星云群中无线电星团的调查：ii。天文学
A VLBA Survey of radio stars in the Orion Nebula Cluster: II. Astrometry
论文作者
论文摘要
从很长的基线阵列（VLBA）观测值中，我们先前确定了123个年轻恒星系统的人群，这些系统具有非热无线电发射，朝着Orion星云群（ONC）的核心。我们在Gaia Dr2目录中发现了34个无线电位置的光源。大多数无线电来源可能是Gaia检测的伴侣。但是，有11个星星的VLBA位置与Gaia $ <1.6 $ MAS不同，其中一些无线电源可能会依次使用无线电的播放量。 VLBA和GAIA数据我们发现ONC的全球运动和速度分散率为（$μ_α*，μ_δ$）=（$ 1.20 \ PM0.09,0.18 \ pm0.09 $） （$σ_{μ_α*}，σ_{μ_δ} $）=（$ 0.84 \ pm0.09,1.30 \ pm0.09 $）MAS yr $^{ - 1} $，我们通过估算标量和矢量产物的方式来寻找有序的动作。 $ \ mathbf {\叠加{年轻的恒星簇处于膨胀，收缩或旋转中。
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 ($μ_α*,μ_δ$)=($1.20\pm0.09,0.18\pm0.09$) mas yr$^{-1}$ and ($σ_{μ_α*},σ_{μ_δ}$)=($0.84\pm0.09,1.30\pm0.09$) mas yr$^{-1}$. Finally, we looked for ordered motions by estimating the means of scalar and vectorial products, which results in $\mathbf{\overline{v\cdot\hat{r}}}=-0.61\pm1.00$ km s$^{-1}$ and $\mathbf{\overline{v\times\hat{r}}}=0.57\pm0.95$ km s$^{-1}$. These do not show indications that the young stellar cluster is in expansion, contraction, or rotation.
