Question

according to the h-r diagram, which of these stars is expected to have the shortest lifespan?

1. red dwarf
2. sun - like star
3. massive blue star
4. white dwarf

Explanation:

The H - R (Hertzsprung - Russell) Diagram helps in understanding stellar evolution. The lifespan of a star is inversely related to its mass (and luminosity, as more massive stars are more luminous). Massive blue stars have a very high mass and thus a very high rate of nuclear fusion, which causes them to exhaust their nuclear fuel quickly. Red dwarfs have low mass and long lifespans, sun - like stars have a moderate lifespan, and white dwarfs are the remnants of stars and not in the main - sequence burning phase (so their "lifespan" in terms of burning fuel is already over, but as a remnant, they cool over a very long time). So among the given options, the massive blue star has the shortest lifespan.

Answer:

1. Massive blue star