Question

hr diagrams

1. on the hr diagram, where can we find the hottest but dimmest stars?
2. what percentage of stars are in their main sequence phase?
3. how many classes of stars are located on the hr diagram and what are the names?

Explanation:

1. On an HR - diagram, the hottest but dimmest stars are white dwarfs, located in the lower - left corner as they have high surface temperatures but low luminosities.
2. Approximately 90% of stars are in the Main Sequence phase. This is a well - established fact based on stellar population studies.
3. There are seven main classes of stars on the HR diagram: O, B, A, F, G, K, and M. These classes are based on surface temperature and spectral characteristics.

Answer:

1. Lower - left corner (white dwarfs)
2. 90%
3. Seven classes (O, B, A, F, G, K, M)