大陵五型双星的自转统计研究

STATISTICAL STUDY OF THE ROTATION OF ALGOLS

本文收集了能计算出同步自转速度和有自转实测数据的91个Algol型双星系统,对这些系统的自转同步性与系统的演化或非演化、子星的相对半径、光谱型等的关系做了统计分析,得出了一些有意义的结果:未演化的系统的同步自转比例明显高于巳演化的系统;对P<10天的系统,同步和非同步的明显分界在γ(?)0.20而不是0.15;按光谱型,A型星的同步性比B型星的要高,其周期界线在2—4天内;而B型星的周期界线约2天.

91 Algols type systems, having radii of components and inclinations of orbits so that their synchronous rotational velocities can be calculated and their V sin i have been measured, are collected. All of them tabulated in Table 1 in which, i is the inclination of orbit, Vk represents the synchronous rotational velocity, alphameans the mass ratio, r is the fractional radius, F=V sin i/Vk. s-semi-detached, d-detached, e-evolred, u-unevolved. The values in the brackets under the column of V sin i were measured by myself. Comparing Fig. 1 and Fig. 2, we conclude that the frequency of the components near synchronizm (F less than 1.5) for unevolved systems is higher than for evolved systems. Fig. 3 shows us the limit r for the Algols with p<10 days is about 0.2, above which synchronizm can be regarded as the rule comes out. There are 50 spectral type B components and 44 spectral type A components with periods shorter than 10 days. The relation of Log f to P for both spectral type A and B is shown in Fig. 4. The shortest period for synchronizm is about 4 days in type A components and 2 days in type B components. Which is quite different from former's results. Most systems having asynchronizm are belong to at least one case of as following, a. long period, small r; b. large orbital ecoentricity; c. some type B stars; d. some giant or suppergiants. We have to note that the values for both stellar radius R and rotational velocity V sin i are quite different from different sources for a lot of stars. As a result that a few systems show synchronizm or not depend on the selection of these values and we can not know their truth.