SS433研究的新进展

SS433是银河系内一个著名的高能天体,W50是它周围的超新星遗迹,自20世纪70年代末SS433的运动模型建立以来,已经受到了越来越多的关注,取得了丰富的多波段观测资料。但是,直到现在,关于这一系统的一些基本性质和参数还存在相当大的争论。该文介绍了关于SS433研究的某些新进展,主要包括SS433的运动模型和喷流的膨胀冷却模型,SS433的物质损失,各种时标的光变和喷流的结构,并对关于SS433研究的热点问题作了总结与展望。

The New Progress on the Research of SS433

SS433 is a famous high energy source in our Galaxy, W50 is the supernova remnant surrounding it. Since the establishment of the kinematical model of SS433 was suggested in 1970, this system has drawn more and more attention. Multi-band observations have been carried out and a lot of data has been obtained. But until now, there are still a lot of debates about the essential nature and parameters of this system. For example, the nature of the compact star, the type of the mass donor star, the acceleration and collimation of the jet are not quite certain. In this article, recent progress on the research of SS433 is described. There are three main periodic motions of SS433, the precession of the relativistic jet, the orbital motion of the binary and the "nodding" of the accretion disk. In section 2.1, more precise parameters of kinematical model from recent observations are given, also the thermal expanding and cooling model of the jet is introduced, which is often used to explain the X-ray emission from the jet. The mass loss process is a very important problem in the study of SS433 and other X-ray binaries. In section 2.2, different kinds of mass loss process are discussed in order to explain the mass loss of SS433. The mass loss rate of stellar wind from the mass donor star may be higher than the mass loss rate of the jet. Disk wind is a little more complicated since it may contain two components, wind vertical to the disk and wind parallel to the disk. The outflow parallel to the disk plane could be observed directly from the high resolution radio observation. From multi-band observations, one can conclude the structure of the disk in different scales, this distorted structure may be related to a lot of observational phenomena of SS433. Since the spatial resolution is limited, variability at different time scales may be the only method to study the fine structure of the central region of SS433. In section 2.3, the problem is discussed, as well as some hot spots like short time scale variability, energy flow with velocity larger than the jet velocity and two kinds of eclipses (secondary eclipse and additional eclipse). Finally, in section 2.4, the structure of the jet from the recent multi-band observations is outlined.