What is different about a massive star's lifetime during the hydrogen fusing phase? Where is this star on the H-R diagram?

During the hydrogen fusing phase, the lifetime of a massive star is significantly shorter compared to a smaller star due to the higher rate of energy production. This phase typically lasts for millions of years for massive stars.

On the Hertzsprung-Russell (H-R) diagram, a massive star during the hydrogen fusing phase would be located in the upper-left portion, known as the main sequence. Massive stars have high luminosity and temperature, placing them towards the top left of the H-R diagram.

During the hydrogen fusing phase, a massive star's lifetime is significantly shorter compared to that of a lower-mass star. This is because massive stars have a higher rate of nuclear fusion in their cores due to their higher mass and density. As a result, they exhaust their hydrogen fuel more rapidly.

To determine where a massive star is located on the Hertzsprung-Russell (H-R) diagram, you need to consider two factors: temperature and luminosity. The H-R diagram plots a star's temperature on the horizontal axis and its luminosity (brightness) on the vertical axis.

Massive stars are classified as "O" or "B" type stars and are found in the upper left portion of the H-R diagram. They have high temperatures and high luminosities. This is because their high mass causes them to burn their fuel at a much faster rate, resulting in higher temperatures and greater energy output.