Question

Which of the following comparisons between low-mass and high-mass main-sequence stars is true?

a) Low-mass stars have shorter lifespans.
b) High-mass stars are cooler than low-mass stars.
c) Low-mass stars undergo supernovae explosions.
d) High-mass stars fuse hydrogen at a faster rate.

Answer 1

d) High-mass main-sequence stars fuse hydrogen at a faster rate, resulting in shorter lifespans compared to low-mass stars. Lifespan is inversely related to luminosity and directly related to mass.

Step-by-step explanation:

The comparison between low-mass and high-mass main-sequence stars that is true is that high-mass stars fuse hydrogen at a faster rate than low-mass stars. This high rate of fusion leads to a much shorter lifespan for high-mass stars despite them containing more fuel. The lifetime of a star on the main sequence is directly proportional to its mass and inversely proportional to its luminosity, following the relationship T = 10ⁱ⁰ My, where T is the lifetime in years, M is the mass relative to the Sun and y factors in the more rapid depletion of hydrogen. Massive main-sequence stars, which have high temperatures and high luminosities, spend fewer years on the main sequence compared to their low-mass counterparts, which are cooler and less luminous. For example, a star with a mass of 1 solar mass can remain on the main sequence for about 10 billion years, while a star with a mass of 0.4 solar mass may have a main-sequence lifetime of roughly 200 billion years, longer than the current age of the universe.