Question

When an interstellar cloud fragment does not have enough mass to form a star powered by nuclear fusion, but gets hot enough to glow for a while, it is called a ________.

1) Protostar
2) Brown dwarf
3) White dwarf
4) Neutron star

Answer 1

A cloud fragment that does not have enough mass to form a star but gets hot enough to glow is called a brown dwarf.

Step-by-step explanation:

When an interstellar cloud fragment does not have enough mass to form a star powered by nuclear fusion, but gets hot enough to glow for a while, it is called a brown dwarf. Brown dwarfs have masses between roughly 1/100 and 1/12 that of the Sun and can produce energy for a brief time by means of nuclear reactions involving deuterium. However, they do not become hot enough to fuse protons and become true stars.