当前位置: X-MOL 学术Astron. Lett. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Kinematics of Hot Subdwarfs from the Gaia DR2 Catalogue
Astronomy Letters ( IF 1.1 ) Pub Date : 2019-11-13 , DOI: 10.1134/s1063773719080012
V. V. Bobylev , A. T. Bajkova

We have studied the kinematic properties of the candidates for hot subdwarfs (HSDs) selected by Geier et al. from theGaiaDR2 catalogue. We have used a total of 12 515 stars with relative trigonometric parallax errors less than 30%. The HSDs are shown to have different kinematics, depending on their positions on the celestial sphere. For example, the sample of low-latitude (|b| < 20°) HSDs rotates around the Galactic center with a linear velocity V0 = 221 ± 5 km s−1. This suggests that they belong to the Galactic thin disk. At the same time, they lag behind the local standard of rest by ΔV ~ 16 km s−1 due to the asymmetric drift. The high-latitude (|b| ≥ 20°) HSDs rotate with a considerably lower velocity, V = 168 ± 6 km s−1. Their lagging behind the local standard of rest is already ΔV ∼ 40 km s−1. Based on the entire sample of 12 515 HSDs, we have found a positive rotation around the x axis significantly differing from zero with an angular velocity ω1 = 1.36±0.24 km s−1 kpc−1. We have studied the samples of HSDs that are complete within r < 1.5 kpc. Based on them, we have traced the evolution of the parameters of the residual velocity ellipsoid as a function of both latitude |b| and coordinate |z|. The following vertical disk scale heights have been found: h = 180 ± 6 and 290 ± 10 pc from the low- and high-latitude HSDs, respectively. A new estimate of the local stellar density Σout = 53 ± 4 M☉ kpc−2 has been obtained for zout = 0.56 kpc from the high-latitude HSDs.

中文翻译:

盖亚DR2目录中热亚矮的运动学

我们已经研究了由Geier等人选择的候选热亚矮(HSD)的运动学特性。来自GaiaDR2目录。我们总共使用了12 515颗相对误差小于30%的恒星。根据其在天球上的位置,HSD具有不同的运动学特性。例如,低纬度(| b | <20°)HSD的样本绕银河系中心以线速度V 0 = 221±5 km s -1旋转。这表明它们属于银河薄磁盘。与此同时,它们滞后由Δ本地标准其余后面V 〜16个公里S -1由于不对称漂移。高纬度(| b| ≥20°)的HSD具有相当低的速度,旋转V = 168 ± 6公里S -1。他们休息的地方标准相对滞后已经Δ V 〜40公里S -1。基于对12周515的HSD整个样品,我们已经发现在围绕正旋转X轴显著不同于零与角速度ω 1 = 1.36±0.24公里S -1 KPC -1。我们研究了在r <1.5 kpc内完成的HSD样本。基于它们,我们跟踪了残余速度椭球参数随纬度|纬度| | | | | b| 和协调 z |。已发现以下垂直磁盘刻度高度:分别从低纬度HSD和高纬度HSD得出h = 180±6和290±10 pc。本地恒星密度Σ的新估计= 53±4中号☉KPC -2已经获得Ž从高纬度的HSD = 0.56 KPC。
更新日期:2019-11-13
down
wechat
bug