For example, in 1764, a cluster of stars known as Messier 30 was discovered by astronomer Charles Messier. While the concept of stellar collision has been around for several generations of astronomers, only the development of new technology has made it possible for it to be more objectively studied. Mass may be thrown off in the orbital plane of the merging stars,Ĭreating an excretion disk from which new planets can form. When two low-mass stars in a binary system merge, While most contact binary stars are stable, a few have become unstable and have merged in the past for reasons not well understood (see relevant section below).
Some binary stars orbit each other so closely that they share the same atmosphere, giving the system a peanut shape. Neutron star mergers Ībout half of all the stars in the sky are part of binary systems, with two stars orbiting each other. In a matter of seconds, all of the white dwarf's mass is thrown into space. Because of this, runaway fusion reactions rapidly heat up the interior of the combined star and spread, causing a supernova explosion. Since a white dwarf consists of degenerate matter, there is no safe equilibrium between thermal pressure and the weight of overlying layers of the star. When they finally merge, if their combined mass approaches or exceeds the Chandrasekhar limit, carbon fusion is ignited, raising the temperature.
Emission of gravitational waves causes the pair to spiral inward. Much more rarely, a type Ia supernova occurs when two white dwarfs orbit each other closely. The normal route by which this happens involves a white dwarf drawing material off a main sequence or red giant star to form an accretion disc. White dwarfs are the remnants of low-mass stars and, if they form a binary system with another star, they can cause large stellar explosions known as type Ia supernovae. Types of stellar collisions and mergers Type Ia supernova