what is the colour of stars from the hottest to the coolest?

Answer 1

The Morgan-Keenan spectral classification is what you need to read up about (and the Hertzsprung-Russell Diagram).

Morgan-Keenan spectral classification

This stellar classification is the most commonly used. The common classes are normally listed from hottest to coldest (with mass, radius and luminosity compared to the Sun) and are given in the following table.

Class Temperature Star colour Mass Radius Luminosity
O 30,000 – 60,000 K Bluish ("blue") 60 15 1,400,000
B 10,000 – 30,000 K Bluish-white ("blue-white") 18 7 20,000
A 7,500 – 10,000 K White with bluish tinge ("white") 3.1 2.1 80
F 6,000 – 7,500 K White ("yellow-white") 1.7 1.3 6
G 5,000 – 6,000 K Light yellow ("yellow") 1.1 1.1 1.2
K 3,500 – 5,000 K Light orange ("orange") 0.8 0.9 0.4
M 2,000 – 3,500 K Reddish orange ("red") 0.3 0.4 0.04

As you can see, as the size drops, so does the (photospheric) temperature and luminosity and the colour alters too.

The Sun is in spectral class G, Each class is subdivided into ten sub-classes by temperature with G0 being the hottest down to G9, The Sun is G2.

Class O
Class O stars are very hot and very luminous, being bluish in colour; in fact, most of their output is in the ultraviolet range. These are the rarest of all main sequence stars, constituting as few as 1 in 32,000. O-stars shine with a power over a million times our Sun's output.

Because they are so huge, Class O stars burn through their hydrogen fuel very quickly, and are the first stars to leave the main sequence. Recent observations by the Spitzer Space Telescope indicate that planetary formation does not occur within the vicinity of an O class star due to the Photo evaporation effect.

Examples: Zeta Puppis, Lambda Orionis

Class B
Class B stars are extremely luminous and blue. Their spectra have neutral helium and moderate hydrogen lines. As O and B stars are so powerful, they only live for a very short time, and thus they do not stray far from the area in which they were formed. These stars tend to cluster together in what are called OB1 associations, which are associated with giant molecular clouds. The Orion OB1 association occupies a large portion of a spiral arm of our Galaxy and contains many of the brighter stars of the constellation Orion. They constitute about 0.13% of main sequence stars -- rare, but much more common than those of class O.

Examples: Rigel, Spica, the brighter Pleiades

Class A
Class A stars are amongst the more common naked eye stars. As with all class A stars, they are white or bluish-white. They comprise perhaps 0.63% of all main sequence stars.

Examples: Vega, Sirius

Class F
Class F stars are still quite powerful but they tend to be main sequence stars. Their colour is white with a slight tinge of yellow. These represent 3.1% of all main sequence stars.

Examples: Canopus, Procyon

Class G
Class G stars are probably the best known, if only for the reason that our Sun is of this class.

Supergiant stars often swing between O or B (blue) and K or M (red). While they do this, they do not stay for long in the G classification as this is an extremely unstable place for a supergiant to be. These are about 8% of all main sequence stars.

Examples: Sun, Capella

Class K
Class K are orangish stars which are slightly cooler than our Sun. Some K stars are giants and supergiants, such as Arcturus while others like Alpha Centauri B are main sequence stars. These make up some 13% of main sequence stars.

Examples: Arcturus, Aldebaran

Class M
Class M is by far the most common class. Over 78% of stars are red dwarfs, such as Proxima Centauri. M is also host to most giants and some supergiants such as Antares and Betelgeuse, as well as Mira variables. The Late-M group hold hotter Brown Dwarfs

Examples: Betelgeuse, Barnard's star
Examples: GSC 08047-00232 B (Late-M Brown Dwarf

The Hertzsprung-Russell diagram relates stellar classification with absolute magnitude, luminosity, and surface temperature.

Answer 2

Sounds like Homework! I'll help though. The more massive stars burn the hottest, the least massive the coolest. This is because the more mass there is, the more gravity there is, and therefore the more pressure at the core there is, and thus more fusion going on there.

Stars do not appear truly red, blue, yellow, or such. They appear white with a very subltle tint of a color. Giant and supergiant stars, though, can be a bit more saturated with color.

That said, think about heating up a piece of iron. When it starts to get hot, it glows red, then yellow, then white, then, if it got hot enough without melting, blue. This is beacuse of the peak wavelength given off at different temperatures, and the effect is the same for stars--the hotter they are, the bluer they are. The cooler, the redder.

Hope this helps!

Answer 3

Giant blue stars are the hottest. I believe brown dwarfs would be the coolest, barely emitting any IR radiation.

Answer 4

For the stars O; B; A; etc, there is a joking memo :

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ciao

Answer 5

White is the hottest blue is next then yallow is the coolest

Answer 6

Red, yellow white blue

Answer 7

the color of stars is a function of it direction related to the earth and no it's tempeture.

Answer 8

red to white

Answer 9

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hope i helped