大质量双星系统的非守恒演化

Non-conservative Evolution of Massive Binary Systems

由于大质量双星系统有强大的星风物质损失，因而在研究其结构和演化时必须考虑星风物质损失、动量损失、物质交换以及由以上原因引起的轨道参量的变化。此外，天文观测又证实，一些大质量双星系统中存在星风冲击波，有X射线辐射以及有致密天体（白矮星，中子星）的存在，因此在研究大质量双星的演化时，又会遇到星风冲击波理论及其对演化的影响，双星系统何时会演化成为有公共外壳的系统，以及双星系统中如果发生超新星爆发，是否会将双星系统破坏等问题。近年来对上述问题的研究已有所进展。

It is known that massive stars have a lot of special features, e.g., they have strong stellar winds and thus great mass loss, high surface temperature and strong radiation pressure, and will evolve into a supernova explosion. If a massive star is at the same time a component of a binary system, it will also be subjected to the effects of the gravitational and the radiational field of its companion star. Thus, the development of the theory of non-conservative evolution of massive binaries will encounter a series of very sophisticated problems such as:Since the rate of mass loss due to stellar wind of a massive star is related to the gravitational acceleration on the surface and the luminosity of the star, thus we have to know the effects of tide, rotation and irradiation on the rate of mass loss.The matter escaping from the surface of a star in the form of stellar wind will take away angular momentum at the same time. Thus, we have to know the relationship between the mass loss and the angular momentum loss.We need to know how the orbital period of the binary system changes when both stars have mass loss and angulal momentum loss and at the same time mass transfer occurs.It is interesting to know, in the case that the stars have very high surface temperature and very strong radiation pressure, how their radiation affects the Roche lobe and the mass transfer.Under certain condition, the two stars can evolve to a system with a common envelope.After the loss of the common envelope, the binary system becomes one with a very short period.It is important to determine the criteria for the two stars to evolve to have a common envelope,and the change in the orbital period of the binary system after the loss of the common envelope.If a component evolves to a supernova, the explosion being another way for significant loss of mass and angular momentum, the questions arise whether the explosion will destroy the binary system and what the criteria are for this to occur.When both stars have stellar wind, the collision of stellar winds will produce a shock front.The hydrodynamic theory of the shock front and the effects of the shock front should be known.All the above problems have been discussed in the present paper.