Chandrasekhar Limit – The Key Factor
Chandrasekhar limit is the maximum mass limit that a star in it’s waning stages can support itself against it’s own gravity and it is the limit beyond which it would become a blackhole, rather than a white dwarfs or neutron stars. The limit is known as ‘Chandrasekhar limit’ and he was awarded Nobel prize for this discovery in 1983.
Hesailed from India in 1928 to study in Cambridge under the British Astronomer Sir Arthur Eddington, who was supposed to be an expert on General Relativity. He had already worked out the radius of a star could be so that it would be able to support it self against its gravity, after all the energy producing nuclear reactions are over. According to Pauli’s exclusion principle, when the star becomes tiny, the matter particles get so close to each other that; their different velocities make them move apart in different directions; making the star bigger.
A star is so supposed to maintain itself at a constant radius, by a balancing of the forces of the Gravity which is the attractive force and the repulsion from the Exclusion principle- in it’s later stages of life; as it was in it’s younger days when the Gravity was balanced by the intensive heat produced by fission and fusion reactions.
His contribution to the scientific community was the idea that Exclusion principle had a limit to provide the necessary repulsion that has to counteract Gravity in such a scenario; as the speed of light is the maximum velocity that matter particles can attain, according to the theory of relativity. So, when the star would become sufficiently dense for the Gravity to overcome the repulsion force given by the velocities of the matter particles; it would collapse on itself and once the process has started, it would in a short time become a black hole – with Gravity so dense that it would distort the space and time around it and most importantly- even the photons won’t be able to escape from it. Chandrasekhar calculated that a cold star which is having a mass about one and a half times the mass of our sun, wouldn’t be able to support itself against it’s gravity and this mass limit for expended stars to become a blackhole is called now ‘ Chandrasekhar Limit”.
TheChandra Observatory site of Harvard university is now one the finest one which has a categorized list of all the star clusters, nebulae, neutron stars which The Hubble Telescope has captured and revolutionized the way we “look at the stars” – to say the least! The pictures are available for public viewing and the recently discovered black hole pictures to the older CygnusX -1 images are available.