Which of these stars will spend the shortest time on the main sequence?
The star that will spend the shortest time on the main sequence is Mintaka, which has a B-V index of -0.40. This means that it is a very hot and blue star, with a spectral type of O9 V. This indicates that it has a high mass and luminosity, and therefore a short main sequence lifetime.
Which will spend the longest time on the main sequence?
The star that will spend the longest time on the main sequence is Bernard’s Star, which has a B-V index of 1.73. This means that it is a very cool and red star, with a spectral type of M4 V. This indicates that it has a low mass and luminosity, and therefore a long main sequence lifetime.