What Critical Event Transforms a Protostar into a Normal Main-Sequence

question 50

Multiple Choice

What critical event transforms a protostar into a normal main-sequence star?

• A) Planets form in the accretion disk.
• B) The star grows suddenly larger in radius.
• C) Triple-alpha reactions begin in the core.
• D) Nuclear fusion begins in the core.
• E) Convection begins throughout the star's interior.