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H r diagram
1.
2. Stars can be classified in three ways:
Size – How massive the star is
Temperature – A star’s color reveals its
temperature.
▪ Red stars have a cooler temperature, and blue stars have a
warmer temperature.
Brightness/Magnitude – The amount of light a star
gives off depends on its size and temperature.
3. How bright a star looks from Earth depends
upon both how far the star is from Earth and
how bright the star actually is.
A star’s brightness can be can be described in
two ways: apparent magnitude and absolute
magnitude.
4. Apparent magnitude is the brightness of a
star as seen from Earth.
Absolute magnitude is brightness of a star as
if it were 32.6 light years from Earth.
The brightness of the stars is compared to the
brightness of our Sun. We call this luminosity.
5. An HR diagram shows the two most
important characteristics of stars, which are
temperature and absolute magnitude
(brightness) and/or luminosity.
Scientists plot the surface temperatures of
stars and their brightness on a graph.
6. An HR diagram shows the two most
important characteristics of stars, which are
temperature and absolute magnitude
(brightness) and/or luminosity.
Scientists plot the surface temperatures of
stars and their brightness on a graph.