The colors of stars range from the coolest reds to the hottest blues. The cool red stars are the dimmest and least massive, while the hot blue stars are the brightest and most massive. In between these extremes are orange, yellow, and white stars.
Red is the color at the lowest end of star temperatures. These "M" class or "red dwarf" stars are by far the most common type of star in our galaxy. They're also very small and faint compared to other types of stars. Most red dwarf stars have a surface temperature between 2,700Â°K (2,430Â°C) and 3,500Â°K (3,230Â°C).
Stars with an surface temperature between 3,500Â°K (3,230Â°C) and 5200Â°K (4 920 C) appear orange to us here on Earth. These include many giant class "K"stars like Arcturus as well as some bright supergiants like Betelgeuse in Orion's shoulder.
The Sun is classified as a G2-type star because it has a surface temperature of around 5800 K (5 530 Â°C). This puts it near the middle of main sequence spectral types for single star systems... which makes it pretty average when compared to all other known stellar objects! Other examples of yellow-hued main sequence dwarfs include Vega and Capella .
A star's color can change over time as it runs out of hydrogen fuel in its core and starts fusing heavier elements like helium instead... this causes them to expand into huge giants or even supergiants! The extra size means their surfaces have cooled down enough that they no longer look bluish-white anymore but more pure white instead.. Examples include Rigel in Orion , Procyon ,and Alderamin .
At around 10 000 K(9 700 Â°C), we start seeing blue hues emanating from a star's surface.. The bluestâ€”and thus hottestâ€”stars tend to be young objects that haven't had time to cool down yet or extremely rare high-mass O-type main sequence dwarfs .