标题： Ap和Am星中的双星 显示英文标题

标题： Binaries among Ap and Am stars

摘要： 长期观测冷Ap星和Am星视向速度的结果如下。 有两个样本，一个是大约100颗Ap星，另一个是86颗Am星。 两者都使用法国普罗旺斯高地天文台（CNRS）的CORAVEL扫描仪进行观测。 在冷Ap星中缺乏短周期双星的现象似乎得到了确认，尽管这可能是观测偏差的结果；有一个系统周期短至1.6天。 可以确定十几个新的轨道，包括一个SB2系统。 考虑到文献和我们工作中68个双星的质量函数，我们得出结论，Bp-Ap星的质量比分布与正常G型矮星相同。 在Am星中，我们发现了52个双星，即60%；其中29个可以计算出轨道。 在这29个中，有7个SB2系统，一个三合星系统和一个四合星系统。 21颗视向速度似乎恒定的恒星以后可能会被发现是高偏心率的长周期双星。 SB1系统的质量函数与冷主序星伴星相容，这也得到了正在进行的光谱观测的支持。 显示英文摘要

摘要： The results of long-term surveys of radial velocities of cool Ap and Am stars are presented. There are two samples, one of about 100 Ap stars and the other of 86 Am stars. Both have been observed with the CORAVEL scanner from Observatoire de Haute-Provence (CNRS), France. The conspicuous lack of short-period binaries among cool Ap stars seems confirmed, although this may be the result of an observational bias; one system has a period as short as 1.6 days. A dozen new orbits could be determined, including that of one SB2 system. Considering the mass functions of 68 binaries from the literature and from our work, we conclude that the distribution of the mass ratios is the same for the Bp-Ap stars than for normal G dwarfs. Among the Am stars, we found 52 binaries, i.e. 60%; an orbit could be computed for 29 of them. Among these 29, there are 7 SB2 systems, one triple and one quadruple system. The 21 stars with an apparently constant radial velocity may show up later as long-period binaries with a high eccentricity. The mass functions of the SB1 systems are compatible with cool main-sequence companions, also suggested by ongoing spectral observations.