A ball of hot and compact magnetized plasma held in equilibrium against its self-gravity by radiation pressure rather than gas pressure. A MECO is so extremely
compact that its own radiation quanta move in almost closed
orbits due to self-gravity. Therefore, though the MECO
is extremely hot and luminous to a local observer it
appears as almost ``Black'' to astronomers.
According to
Abhas Mitra, an Indian
astrophysicist, and several other astrophysicists, the so-called ``Black Hole Candidates'' are actually MECOs rather than true
Black Holes.