Which end state is listed as a possible fate for a star?

• A. Gas giant
• B. Brown dwarf
• C. Moon
• D. Comet

Answer: (B)

Mass determines whether a collapsing cloud becomes a true star that sustains hydrogen fusion. If the object never reaches enough mass, it doesn’t ignite core fusion and becomes a brown dwarf—a substellar object formed like a star but not bright like one. Brown dwarfs occupy roughly 13 to 80 Jupiter masses; they’re not planets, but they’re also not stars.

Gas giants, moons, and comets are not end products of stellar evolution. Gas giants are planets, moons are satellites, and comets are small icy bodies. So the only option that fits as a possible fate for a star-forming object that doesn’t quite become a true star is a brown dwarf.