arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2103.10232astro-ph.GA
收藏

LAMOST A型星的定域动力学和Oort常数

Local Stellar Kinematics and Oort Constants from the LAMOST A-type Stars

F. Wang, H. -W. Zhang, Y. Huang, B. -Q. Chen, H. -F. Wang, C. Wang

备注：
10 pages, 10 figures, accepted for publication in MNRAS
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

我们利用从LAMOST巡天中选出的5，627颗具有$d<0.6\,\rm kpc$和$|z|<0.1\,\rm kpc$的A型恒星的样本估算了太阳的奇特速度和奥尔特常数。用非轴对称模型拟合了这些A型星的径向和切向速度。最佳拟合结果分别得到太阳特有速度$(U_\odot,V_\odot,W_\odot)=(11.69\pm0.68, 10.16\pm0.51, 7.67\pm0.10)\,\rm km\,s^{-1}$和Oort常数$A=16.31\pm0.89\,\rm km\,s^{-1}\,kpc^{-1}$、$B=-11.99\pm0.79\,\rm km\,s^{-1}\,kpc^{-1}$、$C=-3.10\pm0.48\,\rm km\,s^{-1}\,kpc^{-1}$、$K=-1.25\pm1.04\,\rm km\,s^{-1}\,kpc^{-1}$。$|K+C|>4\,\rm km\,s^{-1}\,kpc^{-1}$是指在扩展的局部圆盘中存在径向速度梯度，这意味着局部圆盘处于非对称势中。利用导出的奥尔特常数，我们导出了局部角速度$Ω\,{\approx}\,A-B=28.30\pm1.19\,\rm km\,s^{-1}\,kpc^{-1}$。利用不同体积的A型星样本，进一步研究了$R$-$V_ϕ$平面上的脊型对太阳运动和Oort常数的约束作用。随着体积向反中心方向变大，$A$和$B$的值变大（意味着局部旋转曲线的斜率更陡），而$V_\odot$的值变小，这可能是由于脊结构及其信号随距离增加而引起的。

英文摘要：

We estimate the solar peculiar velocities and Oort constants using a sample of 5,627 A-type stars with $d<0.6\,\rm kpc$ and $|z|<0.1\,\rm kpc$, selected from the LAMOST surveys. The radial and tangential velocities of these A-type stars are fitted by using a non-axisymmetric model. The best-fitting result yields the solar peculiar velocities $(U_\odot,V_\odot,W_\odot)=(11.69\pm0.68, 10.16\pm0.51, 7.67\pm0.10)\,\rm km\,s^{-1}$ and Oort constants $A=16.31\pm0.89\,\rm km\,s^{-1}\,kpc^{-1}$, $B=-11.99\pm0.79\,\rm km\,s^{-1}\,kpc^{-1}$, $C=-3.10\pm0.48\,\rm km\,s^{-1}\,kpc^{-1}$, $K=-1.25\pm1.04\,\rm km\,s^{-1}\,kpc^{-1}$, respectively. $|K+C|>4\,\rm km\,s^{-1}\,kpc^{-1}$ means that there is a radial velocity gradient in the extended local disk, implying the local disk is in a non-asymmetric potential. Using the derived Oort constants, we derive the local angular velocity $Ω\,{\approx}\,A-B=28.30\pm1.19\,\rm km\,s^{-1}\,kpc^{-1}$. By using A-type star sample of different volumes, we further try to evaluate the impacts of the ridge pattern in $R$-$V_ϕ$ plane on constraining the solar motions and Oort constants. As the volume becomes larger toward the anti-center direction, the values of $A$ and $B$ become larger (implying a steeper slope of the local rotation curve) and the value of $V_\odot$ becomes smaller probably caused by the ridge structure and its signal increasing with distance.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑