Chandrasekhar limit

The Chandrasekhar limit  is the maximum mass of a stable white dwarf star. The currently accepted value of the Chandrasekhar limit is about 1.4 M☉ (2.765×1030 kg).

White dwarfs resist gravitational collapse primarily through electron degeneracy pressure (compare main sequence stars, which resist collapse through thermal pressure). 

The Chandrasekhar limit is the mass above which electron degeneracy pressure in the star's core is insufficient to balance the star's own gravitational self-attraction. Consequently, a white dwarf with a mass greater than the limit is subject to further gravitational collapse, evolving into a different type of stellar remnant, such as a neutron star or black hole. Those with masses under the limit remain stable as white dwarfs.

Collapse is not inevitable: most white dwarfs explode rather than undergo collapse.

Origin of the name

The limit was named after Subrahmanyan Chandrasekhar, the Indian astrophysicist who improved upon the accuracy of the calculation in 1930, at the age of 20, in India by calculating the limit for a polytrope model of a star in hydrostatic equilibrium, and comparing his limit to the earlier limit found by E.C. Stoner for a uniform density star.

 Importantly, the existence of a limit, based the conceptual breakthrough of combining relativity with Fermi degeneracy, was indeed first established in separate papers published by Wilhelm Anderson and E. C. Stoner in 1929. 

The limit was initially ignored by the community of scientists because such a limit would logically require the existence of black holes, which were considered a scientific impossibility at the time.


Source adapted from: Wikipedia contributors. (2018, June 16). Chandrasekhar limit. In Wikipedia, The Free Encyclopedia. Retrieved 22:18, June 22, 2018, from https://en.wikipedia.org/w/index.php?title=Chandrasekhar_limit&oldid=846099428