Pre-main sequence stars (not protostars) on the H-R Diagram are _____.
A) above and to the right of supergiants
B) below and to the left of the main sequence
C) below and to the left of white dwarfs
D) above and to the right of the main sequence
E) not on the H-R Diagram yet

Question

Quizplus · Accepted Answer

Pre-main sequence stars are located above and to the right of the main sequence on the Hertzsprung-Russell (H-R) Diagram. This is because they are still contracting and have not yet begun hydrogen fusion in their cores, making them cooler and more luminous than main sequence stars of similar mass.

Pre-Main Sequence Stars (Not Protostars) on the H-R Diagram Are