Final answer:
A brown dwarf is an object with insufficient mass to sustain hydrogen fusion at its core, leading to a halt in gravitational collapse due to electron degeneracy pressure. They have a mass between roughly 1/100 and 1/12 that of the Sun, falling between the mass range of stars and planets. White dwarfs are related but are the remnants of stars whose cores are prevented from collapsing further by the same electron degeneracy pressure.
Step-by-step explanation:
The object described in the student's question is a brown dwarf. A brown dwarf is an object too small to become an ordinary star because electron degeneracy pressure halts its gravitational collapse before fusion becomes self-sustaining. These objects have masses between roughly 1/100 and 1/12 that of the Sun and are intermediate in mass between stars and planets. They may produce energy by nuclear reactions involving deuterium but are not hot enough for sustained proton fusion. White dwarfs are a related concept, being remnants of stars that have undergone complete gravitational collapse with their core contraction being halted by electron degeneracy pressure.
Important to note is the distinction between brown dwarfs and white dwarfs. While brown dwarfs never initiate sustained nuclear fusion, white dwarfs are end states of stars like the Sun that have completed their life cycles. It was the Indian-American astrophysicist Subrahmanyan Chandrasekhar who first calculated how much a star will shrink before degenerate electrons stop its contraction, defining a limit to white dwarf mass and size. Objects of extremely low mass, those below approximately 0.075 times the mass of the Sun, don't reach temperatures high enough to ignite nuclear reactions and are thus classified as brown dwarfs or planets.
At the high densities found within white dwarfs, gravitational forces are extremely strong, but electron degeneracy pressure, as defined by the Pauli exclusion principle, prevents further collapse. This quantum mechanical effect asserts that no two electrons can occupy the same state simultaneously, leading to a pressure that stabilizes the star despite gravitational forces.