  Do observations of black hole candidates rule out alternative theories of
gravity without horizon formation? This depends on the existence, viability and
reasonableness of alternative theories of gravity without black holes.
  Here a theory of gravity without black hole horizon formation is presented.
The gravitational collapse stops shortly before horizon formation and leaves a
stable frozen star. In the limit $\Xi, \Upsilon\to 0$ the Einstein equations of
GR are recovered, and the frozen stars become observationally indistinguishable
from GR black holes. The theory therefore provides a counterexample to recent
claims that observational evidence from black hole candidates "all but requires
the existence of a horizon".
  The theory presented here shares its equations with RTG. Nonetheless, as is
shown, there remain important conceptual and physical differences. In
particular, some serious problems of RTG are not present in the theory proposed
here. So it can be argued that the theory is a physically viable and
conceptually sound alternative to GR.
