Question

Part 1: Describe the mass and surface temperature of the main sequence stars.

Part 2: Explain using complete sentences where on the HR diagram you would expect to find a main sequence star based on its physical properties.

Answer 1

Main sequence is when a star is burning hydrogen in its core. The luminosity and temperature of a main-sequence star are set by its mass. More massive means brighter and hotter. A ten solar mass star has about ten times the sun's supply of nuclear energy.

The main sequence stretching from the upper left (hot, luminous stars) to the bottom right (cool, faint stars) dominates the HR diagram. It is here that stars spend about 90% of their lives burning hydrogen into helium in their cores.