Chandrasekhar limit

The Chandrasekhar limit is the maximum mass that a white dwarf star can have before it collapses into a neutron star or a black hole. It is named after Subrahmanyan Chandrasekhar, an Indian-American astrophysicist who first calculated the limit in the 1930s.

White dwarf stars are the remnants of low to intermediate-mass stars, which have exhausted their nuclear fuel and have shed their outer layers in a planetary nebula. White dwarfs are supported against gravitational collapse by electron degeneracy pressure, which arises from the exclusion principle of quantum mechanics.

As a white dwarf gains mass, its gravity becomes stronger, and the electrons become more tightly packed. When the mass of the white dwarf approaches 1.4 times the mass of the Sun, the electrons become so densely packed that they are forced to combine with protons, forming neutrons. This process is called electron capture.

As the white dwarf continues to gain mass, the neutron degeneracy pressure takes over from the electron degeneracy pressure as the main source of support against gravity. However, if the mass of the white dwarf exceeds the Chandrasekhar limit of about 1.4 solar masses, the neutron degeneracy pressure is not sufficient to stop gravitational collapse, and the star collapses further into a neutron star or a black hole.

The Chandrasekhar limit is an important concept in astrophysics, as it helps to explain the observed properties of white dwarf stars and the evolution of binary star systems, Learning Management System. It also has implications for the study of supernovae, which occur when a white dwarf is triggered to collapse by accretion from a companion star.