Why is there an upper limit to the mass of a white dwarf?
A)White dwarfs come only from stars smaller than 1.4 solar masses.
B)The more massive the white dwarf,the greater the degeneracy pressure and the faster the speeds of its electrons.Near 1.4 solar masses,the speeds of the electrons approach the speed of light,so more mass cannot be added without breaking the degeneracy pressure.
C)The more massive the white dwarf,the higher its temperature and hence the greater its degeneracy pressure.At about 1.4 solar masses,the temperature becomes so high that all matter effectively melts,even individual subatomic particles.
D)The upper limit to the masses of white dwarfs was determined through observations of white dwarfs,but no one knows why the limit exists.
E)Above this mass,the electrons would be pushed together so closely they would turn into neutrons and the star would become a neutron star.

Question

Quizplus · Accepted Answer

The upper limit to the mass of a white dwarf is about 1.4 solar masses, known as the Chandrasekhar limit, because at this point the electrons in the white dwarf are moving at speeds approaching the speed of light, creating a degeneracy pressure that cannot support any more mass without collapsing into a neutron star. The more massive the white dwarf becomes, the faster the speeds of its electrons and the greater the degeneracy pressure. Therefore, adding more mass would require breaking the degeneracy pressure.

Why Is There an Upper Limit to the Mass of a White