The Chandrasekhar Limit

Understanding the Chandrasekhar Limit

• The Chandrasekhar Limit is a concept in stellar astrophysics named after physicist Subrahmanyan Chandrasekhar.
• It specifies the maximum mass of a stable white dwarf star, a key phase in the lifecycle of most stars.
• This limit is approximately 1.4 solar masses. Anything larger than this limit will not become a white dwarf, and will instead follow a different evolutionary pathway.

Relevance of the Chandrasekhar Limit to Stellar Evolution

• During a star’s lifetime, it follows a path of continuous fusion reactions which convert lighter elements to heavier ones to produce energy.
• When a star has exhausted its nuclear fuel, it will shed its outer layers to become a compact white dwarf if its mass is below the Chandrasekhar Limit.
• A star above this mass limit will continue to collapse, evolving into either a neutron star or a black hole.

Chandrasekhar Limit and Supernovae

• A Type Ia supernova is directly tied to the Chandrasekhar Limit.
• This kind of supernova occurs in a binary star system when a white dwarf accretes matter from its companion star and exceeds the Chandrasekhar Limit.
• The excess mass triggers runaway nuclear fusion, leading to a supernova explosion.

Importance of the Chandrasekhar Limit

• The Chandrasekhar Limit has significant implications for our understanding of stellar evolution.
• It plays a crucial role in determining the fate of stars and the formation of exotic celestial objects such as neutron stars and black holes.
• In cosmology, Type Ia supernovae, tied to the Chandrasekhar Limit, are key distance markers and have helped to identify the accelerated expansion of the Universe.