Three Probable Stellar Mass Black Holes.
Abstract
According to the theory of general relativity, a spherically symmetric self-gravitating body whose radius/mass ratio in Schwarzchild coordinates decreases to the critical value of 2 must collapse to a point singularity. Such an object is termed a black hole, since out to a characteristic radius known as the event horizon, not even photons can escape its strong gravitational field. It has been postulated that such a field could serve to compress and heat accreting gas, which would then emit soft X rays, signalling the black hole's presence. One accretion model is that of a black hole in binary orbit with a normal luminous star which is ejecting part of its mass, some of which is captured by the companion black hole and emits X rays before disappearing inside the event horizon. Objects consisting of degenerate nuclear matter known as neutron stars, and whose existence has been well established, could also serve as the X ray companion in such a system. One way to distinguish between a neutron star and a black hole is to measure their mass, for if casualty is to be preserved, a neutron star cannot exceed about 3 solar masses, while the mass of a black hole is arbitrary. A lower limit on the mass of the X-ray emitter in a binary system can be determined if the orbital period, projected orbital velocity, and mass or radius of the luminous companion star can be measured via conventional astronomical methods. Presently, three binary systems so appear to contain an X-ray emitter whose mass exceeds 3 solar masses and must likely be a black hole. They are Cygnus X-1, LMC X-3, and A0620-00. (jhd)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1988
- Accession Number
- ADA196976
Entities
People
- Dale W. Fry
Organizations
- Air Force Institute of Technology