Discussion Overview
The discussion revolves around the sequence of events leading to the formation of stellar-mass black holes from massive stars. Participants explore the uncertainties surrounding whether a massive star's iron core collapses first into an unstable neutron star before forming a black hole, or if the collapse proceeds directly to a black hole. The conversation also touches on the mass gap between neutron stars and black holes and the implications for minimum-mass black holes in the context of quantum gravity.
Discussion Character
- Exploratory
- Debate/contested
- Technical explanation
Main Points Raised
- Some participants propose that the collapse of a massive star could lead to a black hole forming at the center before the conditions for a black hole are met at a larger radius.
- Others argue that the density at the center of a collapsing star could increase without bound, potentially leading to the formation of a minimum-mass black hole.
- There is mention of a mass gap where neutron stars do not exceed 3 M☉ and black holes do not fall below 5 M☉, suggesting a significant aspect of the collapse process that remains unclear.
- Some participants speculate that the tremendous pressure during collapse could allow for the formation of a black hole region that would not form from the star's mass alone.
- There is discussion about whether a "light" black hole could exist after formation, with some suggesting that it would quickly accumulate mass to become a conventional black hole.
- The role of radiation pressure and the effects of gravitational blueshift and redshift on the collapse dynamics are also considered.
Areas of Agreement / Disagreement
Participants express multiple competing views regarding the collapse sequence of massive stars and the formation of black holes, with no consensus reached on the specifics of the process or the implications of minimum-mass black holes.
Contextual Notes
The discussion highlights uncertainties in the collapse mechanisms of massive stars, the role of metallicity in the formation of neutron stars versus black holes, and the potential for intermediate stages in the transition from degenerate matter to black holes. There are also unresolved questions regarding the implications of quantum gravity on black hole formation.