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Stars: Crash Course Astronomy #26

Today Phil’s explaining the stars and how they can be categorized using their spectra. Together with their distance, this provides a wealth of information about them including their luminosity, size, and temperature. The HR diagram plots stars’ luminosity versus temperature, and most stars fall along the main sequence, where they live most of their lives.

Table of Contents
Stars Can Be Categorized Using Their Spectra 1:32
Spectra With Distance Can Identify Luminosity, Size, and Temperature 5:20
The HR Diagram Plots Luminosity vs Temperature 6:33
Most Stars Fall Along the Main Sequence 7:16

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PHOTOS/VIDEOS
Stars [credit: ESA/Hubble & NASA]
Spitzer Spectrum [credit: NASA/JPL-Caltech/Leiden/SRON]
Sun spectrum [credit: N.A.Sharp, NOAO/NSO/Kitt Peak FTS/AURA/NSF]
Annie Jump Cannon [credit: New York World-Telegram and the Sun Newspaper]
Cecilia Payne-Gaposchkin [credit: Smithsonian Institution]
OBAFGKM [credit: NOAO/AURA/NSF]
Betelgeuse [credit: ESO/Digitized Sky Survey 2. Acknowledgment: Davide De Martin]
Sirius [credit: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester)]
Solar AM0 spectrum with visible spectrum background [credit: Danmichaelo, Wikimedia Commons]
Blue sky [credit: Skitter Photo]
Hawaii sunset photo [credit: Phil Plait]
Hertzsprung-Russell Diagram [credit: ESO]