Answer to Question #202923 in Astronomy | Astrophysics for Prachi

Question

 What is planetary nebula? Explain the concept of Chandrasekhar limit.

Answer 1

The planetary nebula is an emission nebula consisting of material ejected from the red giant stars (with initial masses of 1-8 solar mass) at the late stage of their evolution.

A typical planetary nebula is roughly one light year across, and consists of extremely rarefied gas, and the masses of nebulae range from 0.1 to 1 solar mass. Very often at the center of the nebula the white dwarf is observed.

The Chandrasekhar limit is the maximum mass that the white dwarf may have. The value of the limit is near 1.4 solar mass. This is the maximum mass, for which the electron degeneracy pressure may balance the gravity. If the mass is greater than this limit, the object can't be a white dwarf, it can be a neutron star or even a black hole.