1. White Dwarf:
* For stars less massive than about 8 times the mass of our Sun.
* Core collapses into a dense, hot ball of mostly carbon and oxygen.
* Electron degeneracy pressure prevents further collapse.
* Emits a faint, white light and slowly cools over billions of years.
2. Neutron Star:
* For stars with initial masses between 8 and 20 times the Sun.
* Core collapses until protons and electrons combine to form neutrons.
* Neutron degeneracy pressure stops the collapse.
* Extremely dense, with a radius of only about 10-20 kilometers.
* Rotates rapidly and has a strong magnetic field, leading to powerful emissions like pulsars and magnetars.
3. Black Hole:
* For stars with initial masses greater than about 20 times the Sun.
* The core collapses indefinitely, creating a singularity with infinite density.
* Gravity is so strong that not even light can escape, forming a black hole.
* Event horizon marks the boundary beyond which escape is impossible.
Key Points about Collapsed Stars:
* They represent the final stage of a star's life.
* Their formation involves immense gravity and energy release.
* They are extremely dense and compact objects.
* They can emit powerful radiation and have profound effects on their surroundings.
Examples of Collapsed Stars:
* Sirius B: A white dwarf star that is a companion to the bright star Sirius.
* Crab Nebula: A supernova remnant that contains a rapidly rotating neutron star.
* Sagittarius A*: A supermassive black hole at the center of our Milky Way galaxy.
Studying collapsed stars helps us understand the evolution of stars, the nature of gravity, and the fundamental laws of physics. They offer fascinating insights into the extreme conditions that exist in the universe.
