What is the hot core left behind after a low-mass star sheds its outer layers, before it cools?

What is the hot core left behind after a low-mass star sheds its outer layers, before it cools?

• A. Planetary nebula
• B. White dwarf
• C. Neutron star
• D. Black hole

Answer: (B)

In stars like the Sun, the outer layers are shed near the end of the life cycle, creating a glowing shell around the remaining core. That hot, dense core is what becomes a white dwarf. It’s a compact object held up by electron degeneracy pressure, initially very hot and luminous, but it will gradually cool over time. The glowing shell you see is the planetary nebula, not the remnant core. Neutron stars and black holes come from much more massive stars after supernovae, so they’re not the outcome here. The hot core left behind before cooling is the white dwarf.

In stars like the Sun, the outer layers are shed near the end of the life cycle, creating a glowing shell around the remaining core. That hot, dense core is what becomes a white dwarf. It’s a compact object held up by electron degeneracy pressure, initially very hot and luminous, but it will gradually cool over time. The glowing shell you see is the planetary nebula, not the remnant core. Neutron stars and black holes come from much more massive stars after supernovae, so they’re not the outcome here. The hot core left behind before cooling is the white dwarf.