分光双星天龙座θ的光电视向速度观测和新分光解

1985—86年用加拿大自治领天物台视向速度仪观测得到此星23个速度值,和文献中前人数据结合求得此星1898—1986年轨道周期P=3.0707943±0.0000010天,固定P于此值可求得光电视向速度观测的椭圆和圆轨分光解,用Bassett判据选取后者为此单谱双星的新分光解。     

食双星的分光轨道解:WX Cnc

本文首次测定了WX Cnc的分光轨道解。轨道根数是:V_0=+9.8公里/秒;K_1=110.2公里/秒;K_2=149.0公里/秒;T_0=HJD 2,446,480.0309。结合文献中测光结果,得到了WX Cnc的绝对参量:A=6.32R_⊙;R_1=1.53R_⊙;R_2=1.18R_⊙ M_1=1.29M_⊙;M_2=0.96M_⊙。分光质比q=0.74。     

食双星的分光轨道解:BD+37°2356

使用像管摄谱仪和Reticon探测器获得了WUMa型食双星BD+37°2356的高色散和高时间分辨率的光谱,并用交叉相关函数法测定了视向速度。本文首次给出了BD+37°2356的分光轨道解。在圆周运动的条件下,轨道根数测定为:系统的质心速度V_0=-5.3公里/秒;与测光主极小相应的时刻T_0=HJD 2,446,491.8518;视向速度曲线的半振幅K_1=105.1公里/秒;K_2=257.3公里/秒。两子星的光谱型十分相似,在MK系统中分类为F9V,小质量子星的光谱型略早些。两子星的质量比(m_2/m_1)为0.41,星等差(～B)为0.73。     

食双星的分光轨道解:AA UMa

使用像管摄谱仪和Reticon探测器获得了食双星AA UMa的高色散和高时间分辨率的光谱,并用交叉相关函数法测得其视向速度。从光谱特征来看,AA UMa是一对W UMa型食双星。本文首次给出了AA UMa的分光轨道解。在圆周运动的假设下,轨道根数测定为:P=0.468171天;T_0(相应于测光主极小时刻)=HJD2,446,520.4448;K_1=124.0公里/秒;K_2=227.7公里/秒。像其他一些使用本方法获得分光轨道解的食双星一样,AA UMa系统的质心速度没有能够唯一地确定,但是V_0=-34.8公里/秒可能是一个较好的估值。根据分光轨道根数,本文给出了新的测光历元公式:HJD Min I=2,446,520,4448(8)+0.468171(48)·E。AA UMa两子星的光谱型十分相似,与变星总表(GCVS)所列的GoV相一致。两子星的质量比为0.54,星等差为0.36(～B)     

Spectroscopic binaries near the north Galactic pole paper 8: HD 121844

Photoelectric radial-velocity measurements show that HD 121844 is a spectroscopic binary with a period of 303 days, a high eccentricity (0.49) and a high negative γ-velocity (- 61 km s^-1).     

Spectroscopic binaries near the North Galactic Pole paper 14: HD 118234

Photoelectric radial-velocity measurements show that the Seventh-magnitude star HD 118234 is a spectroscopic binary in a very eccentric 59-day orbit.     

Spectroscopic binaries near the north Galactic pole paper 7: HD 107742

Photoelectric radial-velocity measurements show that HD 107742 is a spectroscopic binary with a period of 875 days and a small (but definitely non-zero) eccentricity. The star is not a member of the Coma Cluster, against which it is seen projected.     

Spectroscopic binaries near the North Galactic Pole paper 16: HD 116093

Photoelectric radial-velocity measurements show that HD 116093 is a double-lined spectroscopic binary in a very eccentric 53-day orbit. Very little else is known about the system, but circumstantial evidence is consistent with the hypothesis that the components’ types are near to F3 V and F8 V. If that is so, the orbit must be seen very nearly edge-on; a search for eclipses is warranted and an ephemeris for them is given.     

Stability of S-type Orbits in Binaries

This numerical investigation is concerned with the stability of planets moving around one component of a double star system. Since the discovery of four extra solar planets moving in such orbits, there is a growing interest of stability studies thereto. We determined the stable regions in the elliptic restricted three body problem, for the whole range of mass-ratios from 0.1 to 0.9, by means of the Fast Lyapunov Indicators. The computations have been carried out for eccentricities of the binary and of the planet in the range 0–0.5. Therefore, we present for the first time the variation of the stable regions when the initial eccentricity of the planet is increased. We have found a correlation between the reduction of the stable zones if the eccentricity of the planet or of the binary is increased — of course the latter one is more effective.This revised version was published online in October 2005 with corrections to the Cover Date.     

Spectroscopic binaries near the North Galactic Pole paper 23: HD 111154

HD 111154 is a member of the Coma Cluster. It is here shown to be a somewhat unequal pair of stars of approximately solar type. They are in an orbit that has a period of just under 27 days and quite a high eccentricity (0.442). Although the minimum masses (1.08 and 1.00M _⊙) are large enough to encourage a search for eclipses, no such events have been detected.     

Spectroscopic binaries near the North Galactic Pole paper 18: HD 118670

Photoelectric radial-velocity measurements show that HD 118670 is a double-lined spectroscopic binary in an orbit which is not quite circular and whose period is about 48 days. Spectral types of K0 V and K7 V would satisfy the photometry and the mass ratio; the mass function would then suggest the possibility of eclipses. However, actual spectral classification indicates a luminosity somewhat above the main sequence