Bibcode
Miller, J. C.; Shahbaz, T.; Nolan, L. A.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, vol. 294, p. L25-L29
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2
1998
Citations
31
Refereed citations
21
Description
We examine the status of the threat posed to stellar-mass black hole
candidates by the possible existence of Q-stars (compact objects with an
exotic equation of state that might have masses well above the normally
accepted maximum for standard neutron stars). We point out that Q-stars
could be extremely compact (with radii less than 1.5 times the
corresponding Schwarzschild radius), making it difficult to determine
observationally that a given object is a black hole rather than a Q-star
unless there is direct evidence for the absence of a material surface.
On the other hand, in order for a Q-star to have a mass as high as that
inferred for the widely favored black hole candidate V404 Cygni, it
would be necessary for the Q-matter equation of state to apply already
at densities an order of magnitude below that of nuclear matter and this
might well be considered implausible on physical grounds. We also
describe how rotation affects the situation and discuss the prospects
for determining observationally that black hole candidates are not
Q-stars.