|We know that the sun is not the biggest star, but
is it the hottest star?-Thanks. |
|Question Date: 2013-04-10|
Great question! The sun is really hot: about 10
million degrees Celsius, but it is not the hottest
star in the Universe! Some stars reach
temperatures of 3 billion degrees. That’s 300
times hotter than the sun!
The sun is actually "average" in terms of how hot
and how big it is! There are many starts (blue and
white stars, for instance) that burn hotter than
The hottest stars are blue giants. For example,
Eta Carinae is about 180 times the size (diameter)
of our sun, and has a surface temperature of 40
000 degrees Celcius (72 000 F).
(Our sun looks white from space, and has a
surface temperature of 6000 C (10 000 F). More
recently, in 2005 a star at the center of the Red
Spider Nebula was found to have a temperature of
300 000 C (540,000 F). It's so hot that it doesn't
glow blue, it actually glows X-ray...
(X-ray isn't a color, obviously, but the energy
of the emitted light is so high that it's
invisible, and largely in the same energy as
No, the sun has a pretty average temperature
for a star: there are much hotter stars, and there
are much cooler stars as well.
Did you know that the color of a star is
related to its temperature? If a star looks red,
that means its surface temperature is
approximately 2,500 Kelvin (where Kelvin is
another system to talk about temperature like
Fahrenheit or Celcius). Our Sun, which is a white
star, is about 6,000 Kelvin. That´s hot, right!
But the hottest stars are the blue stars. When a
star gets above 10,000 Kelvin it´s surface appears
blue to our eyes. And the hottest stars are the
very big blue stars, which we call blue
hypergiants. These stars are more than 100 times
larger than the Sun. On example of one of these
very big, very hot stars is the star Eta Carinae
which is about 7,500 light years away from the
Sun. Eta Carinae is more than 180 times larger the
Sun and its surface temperature is around 40,000
Kelvin. That´s 72,000 degrees Fahrenheit (and for
comparison, your body temperature is 98.6 degrees
Fahrenheit... so 72,000 is very very hot!!
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