Galactic kinematics of cepheids from Hipparcos proper motions
Galactic kinematics of cepheids from Hipparcos proper motions
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DOI：
10.1093/mnras/291.4.683
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发表时间：
1997-11-11
影响因子：
4.8
通讯作者：
Whitelock, P
中科院分区：
文献类型：
--
作者：
Feast, M;Whitelock, P
本文分析了220颗造父变星的Hippnrcos自行和有关的地基测光。银河系旋转的影响非常清楚。导出了Oort常数的平均值A = 14.82 +/- 0.84 km·s（-1）kpc（-1）和B = -12.37 +/- 0.64 km·s（-1）kpc（-1），以及太阳圆自转角速度的平均值Omega（o）= 27.19 +/- 0.87 km·s（-1）kpc（-1）。A的值与最近的径向速度解的值的比较证实，在误差范围内，零点的周期光度和周期光度颜色的关系直接来自于依巴谷三角函数的相同的恒星。自行结果表明，银河系自转曲线在距银河系中心太阳距离[（d Theta/dR）（o）= -2.4 +/-1.2 km s（-1）kpc（-1）]处缓慢下降。太阳向北银河系极运动的分量为+ 7.61 +/- 0.64 km s（-1）。根据本文推导的增加的距离尺度，在以前的径向速度研究中推导出的到银河系中心的距离增加到Ro = 8.5 +/- 0.5 kpc。
The Hippnrcos proper motions of 220 Galactic Cepheids, together with relevant ground-based photometry, have been analysed. The effects of Galactic rotation are very clearly seen. Mean values of the Oort constants, A = 14.82 +/- 0.84 km s(-1) kpc(-1) and B = -12.37 +/- 0.64 km s(-1) kpc(-1), and of the angular velocity of circular rotation at the Sun, Omega(o) = 27.19 +/- 0.87 km s(-1) kpc(-1), are derived. A comparison of the value of A with values derived from recent radial velocity solutions confirms, within the errors, the zero-points of the period-luminosity and period-luminosity-colour relations derived directly from the Hipparcos trigonometrical parallaxes of the same stars. The proper motion results suggest that the Galactic rotation curve is declining slowly at the solar distance from the Galactic Centre [(d Theta/dR)(o) = -2.4 +/- 1.2 km s(-1) kpc(-1)]. The component of the solar motion towards the North Galactic Pole is found to be + 7.61 +/- 0.64 km s(-1). Based on the increased distance scale deduced in the present paper, the distance to the Galactic Centre derived in a previous radial velocity study is increased to R-o = 8.5 +/- 0.5 kpc.