What remains after a lower-mass star like the Sun gently sheds its outer layers?

Answer

A white dwarf remnant composed mostly of carbon and oxygen

Lower-mass stars conclude their lives by ejecting their outer material to form a planetary nebula, leaving behind a dense, hot remnant core composed primarily of carbon and oxygen.

What remains after a lower-mass star like the Sun gently sheds its outer layers?
ElementhydrogenstarFusion