Why do stars up there in the sky have different colors?

Answer 1

Google the phrase "Morgan-Keenan Spectrial Classification of Stars" and, as the newspaper vendors would shout, "Read All About It".

Stars are classified according to their photospheric temperature and the colour of the light they emit. The Sun is a G-type yellow star : G2V Among G-type stars, there are ten distinct temperature ranges from G0 (hotter) down to G9 (cooler), The V refers to it being a Main Sequence star, fusing hydrogen to make helium in its core.

78% of stars are red dwarfs. The Pleiades open cluster contains a lot of young (100,000 years or so) hot blue stars.

Stars as they get older can change their spectral classsification, eg the sun is expected to swell up (in 5 billion years' time) into a red giant for about 100,000 years and then become a white dwarf, a spent force, about the size of the earth.

The main types are:

Class Temperature (degrees Kelvin) Star colour
O 30,000 - 60,000 K Bluish ("blue")
B 10,000 - 30,000 K Bluish-white ("blue-white")
A 7,500 - 10,000 K White with bluish tinge ("white")
F 6,000 - 7,500 K White ("yellow-white")
G 5,000 - 6,000 K Light yellow ("yellow")
K 3,500 - 5,000 K Light orange ("orange")
M 2,000 - 3,500 K Reddish orange ("red")

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.

Examples: Zeta Puppis

Class B
Class B stars are extremely luminous and blue. As O and B stars are so powerful, they live for a very short time. They do not stray far from the area in which they were formed as they don't have the time. They therefore tend to cluster together in what we call OB1 associations, which are associated with giant molecular clouds. The Orion OB1 association is an entire spiral arm of our Galaxy (brighter stars make the spiral arms look brighter, there aren't more stars there) and contains all of the constellation of Orion. They constitute about 0.13% of main sequence stars -- rare, but much more common than those of class O.

Examples: Rigel, Spica

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. G is host to the "Yellow Evolutionary Void". 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 if we go by the number of stars. All the red dwarfs go in here and they are plentiful; 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. Titanium oxide can be strong in M stars. The red color is deceptive; it is because of the dimness of the star. When an equally hot object, a halogen lamp (3000 K) which is white hot is put at a few kilometers distance, it appears like a red star.

Examples: Betelgeuse, Barnard's star

Answer 2

it depends on their temperature. The hotter a body, the more energetic the radiation it emits. The more energetic, the shorter the wavelength of that radiation.

The shortest wavelength for visible light is towards the blue end of the spectrum, and the longest is towards the red end. The hottest stars are blue, in between stars are white, slightly cooler ones are yellow, cooler ones still are red.

Up to a point, this is a bit like when you heat a metal rod over a fire: first red, then orange, then yellow, then white, then blueish.

Hope this helps

Answer 3

as you already know stars are sun's that are far away, the different colors are a result of the tempuratures of these sun's. blue for the coldest, yellow for a medium temp, red for high temp, and white for the highest temps, and the planets in our solar system could also be mistaken for stars. at a certain time of year jupiter can be seen in the sky, it looks like a star too

Answer 4

It depends on the temperature of the star. Cooler stars emit a reddish color. Hotter stars are whitish-blue.

Answer 5

it's kind of an involved question--if you know about wave lengths, the visible light spectrum, and the Doppler affect, then it's simple.

There are waves (like heat waves, light waves, ultraviolet light waves, infrared waves) that come from every object. Think of the sound of a motorcycle as it is coming toward you, then going away from you. It has sound waves that hit you at a higher frequency as it comes toward you (so the pitch is higher), and the sound waves come at a slower frequency as it moves away. But the sound is always constant for the rider.

Stars out in space are giving off light. Depending on which way they are orbiting (away from us or toward us), the light will look different--either higher frequency (like the motorcycle coming toward us) or lower frequency (going away). The light we see depends on the frequency of those waves, how fast they are coming at us.

Sometimes the light goes through some pollution in our atmosphere, so that's always nice. (sarcasm). That will change the color of the light too.

Answer 6

the stars differ in their colors because of their temperature and of course their age... a star is blue when it's really very hot and is still young when it's color turns to red it means it's already getting cold and also very old....

hope this little answer somehow answers your question... c;

Answer 7

Like people, they would be bored if they were all the same.

Seriously, it is because they have different temperatures, causing them to emit different wavelengths of light.
They move at different velocities relative to us, causing different Doppler (red)shifts.
They also have different masses, which also changes the color of light they emit.

Answer 8

the temperature of the stars (white=hotter red=cooler) and also doppler effect

Answer 9

The color u see is due to refraction of light.