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learn about stars in detail
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Lecture notes of 2 pages for the course All of Astrophysics at AQA (ye)
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Classification of starsStars in the universe may look the same colour in the universe,
but that’s not the case. Stars are classified by luminosity,
intensity and apparent magnitude and Absolute magnitude.
The apparent magnituse is how far away the object is from Earth
measured in parsec. In order to find the distance or magnitude of
an object, you use:
m-M = 5logd/10
The absolute magnitude of an object is what its apparent mgnitude
would be if it were 10 parsecs away from Earth.
Remember: 1 parsec = 3.08 x 1013km
Astrophysicists often don’t use parsec but they use Astronomical
unit, which is equivalent to the distance from Earth to Sun. (1.5
x 1011m)
Most likely they will use Light year to find distances from Earth
to other planets. 1 light year is 9.46 x1015m.
Stars are classified with temperature as well. A scientist named
Stefan came up with an equation which consisted of, the luminosity
of a black body radiator is directly proportional to the surface +
temperature powered by 4 and he came up with a constant standing
with 5.67 x 10-8W m-2 k-4
Another scientist came up with an idea and graph which came up
with an idea that the wavelengths emited by black bodies decrease
as it gets hotter. This means that Wein’s law notes that the
intensity of light emitted by a star follows the inverse square
law, meaning that intensity is inversely proportional to the
distance between the star and the observer.
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