Class O stars are the hottest of stars with temperatures greater than 30,000oK
Small hot stars are classified as type O, B, or A stars based on their spectral characteristics. These stars are typically blue-white in color and have high surface temperatures and luminosities. They are also referred to as main sequence stars because they are actively fusing hydrogen into helium in their cores.
O. This is the class of the blue/white giants.
T Tauri stars are pre-Main Sequence stars which are large but not as hot as O and B Main Sequence stars. They mainly fall in the categories of F, G, K or M, and they are not yet on the Main Sequence because they are still accreting mass and are still very young and unstable.
All stars are hot. Blue stars are the hottest.
The seven types of main sequence stars in the universe are O (blue and hot), B (white-blue and hot), A (white and hot), F (yellow-white and medium), G (yellow and medium), K (orange and cool), and M (red and cool).
hot, bright stars
Hot.
Hot.
hot,dim stars.
Red stars are cooler than stars of other colors but are still quite hot, which is why the glow red.
All stars are hot, though they vary greatly in temperature.
There is no such thing as a star that is not hot.