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The Question
(Submitted April 08, 1997)
I have looked in and read many great books on astronomy
but never found an answer to this question: Do green stars
exist? If they don't why don't they? Is it theoretically
possible to have a green star? And if they do exist how
would they be classified(main sequence,supergiant,etc.)?
The Answer
Yes, stars of every color in the rainbow exist. In
fact a star's color tells us something very important about
it -- its temperature.
The visible spectrum goes as: Red, Orange, Yellow, Green, Blue and
Violet with a red photon having less energy than Blue. So, blue stars
are hot and red stars are cool (cool for stars that is).
The reason that people do not often mention green stars is simply
that green is in the middle of the visible spectrum. Therefore a
star that gives off a plurality of its light in the green (similar to
our Sun), also gives off lots of red, orange, yellow, blue and violet
light. When we see this mixture of colors it usually appears white or
yellow.
Sincerely,
Jonathan Keohane
-- for Imagine the Universe!
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