What is the dense, small remnant left behind after a supernova from a high-mass star, notable for a strong magnetic field and radio emission?

What is the dense, small remnant left behind after a supernova from a high-mass star, notable for a strong magnetic field and radio emission?

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

Answer: (C)

After a core-collapse supernova from a massive star, the collapsed core can become a neutron star—an incredibly dense object with about the Sun’s mass packed into a sphere only about 10 kilometers across. It carries an extremely strong magnetic field and can emit beams of radio waves as it spins, which we detect as pulsars. This combination of extreme density, huge magnetic field, and radio emission is the hallmark of a neutron star. White dwarfs are remnants of less massive stars and are much less dense, not the compact remnant produced by a core-collapse supernova. Planetary nebulae are just the expelled outer layers of dying low- to mid-mass stars, not compact remnants. Black holes can form if the core mass is too large, but they don’t produce the same pulsar-like radio emission.

After a core-collapse supernova from a massive star, the collapsed core can become a neutron star—an incredibly dense object with about the Sun’s mass packed into a sphere only about 10 kilometers across. It carries an extremely strong magnetic field and can emit beams of radio waves as it spins, which we detect as pulsars. This combination of extreme density, huge magnetic field, and radio emission is the hallmark of a neutron star. White dwarfs are remnants of less massive stars and are much less dense, not the compact remnant produced by a core-collapse supernova. Planetary nebulae are just the expelled outer layers of dying low- to mid-mass stars, not compact remnants. Black holes can form if the core mass is too large, but they don’t produce the same pulsar-like radio emission.