What prevents a brown dwarf from undergoing nuclear fusion?
A) Degeneracy pressure halts the contraction of a protostar so the core never becomes hot or dense enough for nuclear fusion.
B) There is not enough mass to maintain nuclear reactions in a self-sustaining way.
C) The surface temperature never rises high enough for the radiation to be trapped and heat their interior to the temperatures required for nuclear fusion.
D) Radiation pressure halts the contraction of a protostar so the core never becomes hot or dense enough for nuclear fusion.
E) There are too many heavy elements and not enough hydrogen for fusion to occur in a self-sustaining way.
Answer: A