Question

The more massive the star is, the faster it evolves in general. But black hole candidates in binary systems (which are presumably the compact remnants of ordinary stars) are sometimes less massive than their ordinary star companions. Resolve this paradox.

Answer 1

Black hole candidates in binary systems may be less massive than their companions due to mass loss during their evolution, including supernova explosions. The black hole that forms can have a wide range of masses, typically between 4 to 15 times the mass of the Sun, depending on the star's mass, composition, and interaction with its companion star.

Step-by-step explanation:

The paradox of black hole candidates in binary systems being less massive than their ordinary star companions, despite the general rule that more massive stars evolve more quickly, can be understood by considering stellar evolution and mass exchange in binary star systems. As a massive star goes through its life cycle, it sheds mass in a supernova explosion, leaving behind a black hole, which can be less massive than the star it originated from. The presence of the black hole can be inferred by its gravitational effects on its companion star, especially when it begins to expand, potentially transferring mass to the black hole.

The mass of black holes in binary systems typically ranges from 4 to 15 times the mass of the Sun, but the end states of stars can vary based on their mass, composition, and interactions with companion stars—leading to a wide range of behaviors and final masses. Not all of the original mass of the progenitor star contributes to the mass of the black hole, as some of it is lost due to the energy released during the star's lifetime and the supernova explosion.