What is an object called if it fails to reach the temperature for sustained hydrogen fusion?
Answer
Brown Dwarf
The defining characteristic of a true star is the sustained nuclear fusion of hydrogen in its core, a process requiring a critical internal temperature of roughly one million degrees Kelvin. If a collapsing core, even after prolonged gravitational contraction, falls short of reaching this necessary thermal threshold, it becomes classified as a Brown Dwarf. These objects exist in a transitional state: they are far too massive to be considered gas giant planets but lack the requisite mass to ignite and sustain the primary stellar energy source. Consequently, Brown Dwarfs spend their existence slowly cooling down, their initial faint heat source gradually dissipating.
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