A protostar's evolutionary "track" in the H-R diagram traces out:
A) only how the protostar's radius changes with time
B) how the protostar's luminosity, temperature, and radius change with time
C) only how the protostar's luminosity changes with time
D) only how the protostar's spectral type changes with time
E) the protostar's location in the molecular cloud

Question

Quizplus · Accepted Answer

The H-R diagram plots a star's luminosity (vertical axis) against its temperature or spectral type (horizontal axis). As a protostar evolves, its luminosity, temperature, and radius change with time, so its track on the H-R diagram will show those changes over time.

A Protostar's Evolutionary "Track" in the H-R Diagram Traces Out