Question

rank the following stars from the h - r diagram in order of luminosity from brightest to dimmest:
barnards star, betelgeuse, pollux, spica a, sirius b
(3 pts)
brightest
smallest

Explanation:

Step1: Recall H - R diagram luminosity

On the H - R diagram, Betelgeuse is a super - giant star with very high luminosity. Spica A is a main - sequence star (but relatively luminous among the given), Pollux is a giant star, Sirius B is a white dwarf (low luminosity), and Barnard's Star is a red dwarf (very low luminosity).

Step2: Compare luminosities

Super - giants (Betelgeuse) have higher luminosity than giants (Pollux), which have higher luminosity than main - sequence stars (Spica A in this comparison context relative to the others), white dwarfs (Sirius B) are less luminous than main - sequence stars in general for this set, and red dwarfs (Barnard's Star) are the least luminous.

Answer:

Betelgeuse, Spica A, Pollux, Sirius B, Barnard's Star