Which process leads to the formation of a black hole from a massive star?

• A. A massive star gradually cools and contracts until it becomes a black hole without any explosive event.
• B. A massive star loses all its mass through stellar winds, leaving only a black hole behind.
• C. The core of a massive star collapses under gravity after it exhausts its nuclear fuel, resulting in a supernova explosion and leaving behind a black hole.
• D. A massive star merges with a neutron star to directly form a black hole.

Answer: (C)

Verified step by step guidance

1. Understand that a black hole forms from the remnants of a massive star after it has exhausted its nuclear fuel.
2. Recognize that when the core of a massive star runs out of fuel, it can no longer support itself against gravitational collapse.
3. Know that this collapse causes the core to shrink rapidly, leading to a supernova explosion which expels the outer layers of the star.
4. After the supernova, if the remaining core's mass is above a certain limit (the Tolman–Oppenheimer–Volkoff limit), gravity overwhelms all other forces, causing it to collapse into a black hole.
5. Therefore, the key process is the gravitational collapse of the core following the supernova explosion, not gradual cooling, mass loss alone, or merging with another star.