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Re: [Phys-l] sun's true color



If the color of a star is the color we observe with our eyes, then there
are indeed green stars. I'm surprised many astronomers say green stars
don't exist, because many observational astronomy buffs know that they
do. Of course the green color we observe is not the blackbody radiation
color itself, but is the color we perceive after the light has passed
through other stuff, either in the space surrounding the star, or in the
corona itself.

If you want to observe colored stars, it's a lot of fun to observe
double stars of contrasting color. Unfortunately these are often hard
to find by star hopping, but they are easily found if you know their
names or their celestial coordinates, and you have an 8-inch or larger
"goto telescope" that is accurately aligned.

There are two double stars in Hercules that are each classified as as
consisting of one red star and one green star. These are alpha-Hercules
and 95-Hercules. I always try to find these for my astronomy class, and
the students and I all agree that the "green" star truly appears green,
although some will say bluish-green, and the color does seem to vary a
little from time to time.


Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton University
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu