How does the luminosity of a protostar compare to the main-sequence star it will eventually become?

Answer

It can be over a hundred times brighter

During the initial phase of gravitational contraction and accretion, a protostar can be surprisingly luminous, radiating energy at a rate exceeding one hundred times the brightness of the stable main-sequence star it is destined to become.

How does the luminosity of a protostar compare to the main-sequence star it will eventually become?
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