A black hole is most likely to form as the final stage of stellar evolution for which type of main-sequence star?

• A. A star with an initial mass greater than $20M_{☉}$
• B. A low-mass star with an initial mass less than $0.5M_{☉}$
• C. A star with an initial mass similar to the Sun, about $M_{☉}$
• D. A star with an initial mass between $1.4$ and $3$ times the mass of the Sun

Answer: (A)

Verified step by step guidance

1. Understand that the final stage of stellar evolution depends primarily on the initial mass of the star on the main sequence.
2. Recall the general mass ranges and their typical end states: low-mass stars (less than about 0.5 solar masses) end as white dwarfs; stars with masses similar to the Sun (around 1 solar mass) also end as white dwarfs after going through red giant and planetary nebula phases.
3. Recognize that stars with initial masses between about 1.4 and 3 solar masses can end as neutron stars after a supernova explosion, due to the Chandrasekhar limit and the Tolman–Oppenheimer–Volkoff limit.
4. Identify that stars with initial masses greater than approximately 20 times the mass of the Sun have enough mass to collapse beyond the neutron star stage, forming black holes after a supernova or direct collapse.
5. Conclude that the most likely stars to form black holes are those with initial masses greater than 20 solar masses, because their core collapse overcomes neutron degeneracy pressure, leading to black hole formation.