How many species of stars?

There are billions of stars in the universe, each belonging to different types and classifications. Some common types of stars include main sequence stars, red giants, white dwarfs, and neutron stars. The exact number of star species is difficult to determine, but there are estimated to be around 100 billion stars in our galaxy alone.

There are many different ways to classify stars, and each classification system results in a different number of species. One common classification system divides stars into seven spectral types: O, B, A, F, G, K, and M. These spectral types are based on the temperature of the star, with O stars being the hottest and M stars being the coolest.
Within each spectral type, there are further subdivisions based on other factors such as luminosity, mass, and age. For example, the Sun is a G2V star, which means that it is a yellow dwarf star with a luminosity that is about 0.2% of the luminosity of the Sun.
Overall, there are likely to be millions of different species of stars in the universe. However, only a small fraction of these species have been observed and classified.