脉冲星(pulsar)

全名脉冲无线电星（pulsating radio star）

宇宙天体的一类，表现出发射极度有规律的无线电波脉冲的特徵。少数几个也发出可见光、X射线和伽马射线的短州周期脉冲。1967年休伊什和贝尔.伯奈尔（Jocelyn Bell Burnell）用专门设计的无线电望远镜发现了它们，认为是快速自旋的中子星。至今已发现的脉冲星达五百颗以上。所有的表现都相似，但脉冲之间的间隔不同，范围在1秒钟的千分之一到4秒钟之间。从表面发出的带电粒子进入星体的磁场，磁场将它们加速，使得它们产生辐射，从磁极处以强粒子束释放出来。辐射束的方向与脉冲星自转轴方向不一致，因此当星体自旋时，辐射束像灯塔般来回摆动，看起来就像是脉冲。已经证明无线电脉冲星一直在减速，典型的减慢速度为每年百万分之一秒。计算得知约一千万年後脉冲星的磁场变得足够弱时，脉冲星就会「熄灭」。

English version：

pulsar

Any of a class of cosmic objects that appear to emit extremely regular pulses of radio waves. A few give off short rhythmic bursts of visible light, X rays, and gamma radiation as well. Thought to be rapidly spinning neutron stars, they were discovered by Antony Hewish and Jocelyn Bell Burnell in 1967 with a specially designed radio telescope. More than 500 have been detected since. All behave similarly, but the intervals between pulses range from one-thousandth of a second to four seconds long. Charged particles from the surface enter the star's magnetic field, which accelerates them so that they give off radiation, released as intense beams from the magnetic poles. These do not coincide with the pulsar's own axis of rotation, so as it spins the radiation beams swing around like a lighthouse and they are seen as pulses. Radio pulsars have been shown to be slowing down, typically by a millionth of a second per year. It has been calculated that pulsars “switch off” after about 10 million years, when their magnetic fields weaken enough.

参考文章

• 光学脉冲星天文天体
• 黑寡妇脉冲星天文天体
• 脉冲星天文天体