What mechanism primarily generates temporary heat and light in objects like brown dwarfs that cannot sustain core hydrogen fusion?

Answer

Kelvin-Helmholtz mechanism

Objects below the hydrogen fusion threshold generate temporary luminosity through gravitational contraction. This process, known as the Kelvin-Helmholtz mechanism, heats the interior as the object slumps inward.

What mechanism primarily generates temporary heat and light in objects like brown dwarfs that cannot sustain core hydrogen fusion?
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