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Cosmic Perspective Sec. 15.1Cosmic Perspective Sec. 15.1

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Explain how knowledge of Stefan-Boltzmann law leads to understanding of temperatures and radii of stars.

Summarize the circumstances under which objects produce thermal (continuous), emission line, or absorption line spectra.

Explain what is meant by the spectral sequence of stars.

OO BB AA FF GG KK MM L L T T

4 Explain what is meant by the spectral sequence of stars

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0 1 2 3 4 5 6 7 8 9

0 1 2 3 4 5 6 7 8 9

0 1 2 3 4 5 6 7 8 9

0 1 2 3 4 5 6 7 8 9

0 1 2 3 4 5 6 7 8 9

0 1 2 3 4 5 6 7 8 9

0 1 2 3 4 5 6 7 8 9

Explain what is meant by the spectral sequence of stars

http://www.astro.uiuc.edu/~kaler/sow/class-g.html

6 Explain what is meant by the spectral sequence of stars

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Explain what is meant by the spectral sequence of stars.

OO BB AA FF GG KK MM L L T T

What condition in the atom is needed to produce Balmer lines?

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c = 299,792,458 meters per second

Dealing with Measurement UncertaintiesDealing with Measurement Uncertainties

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Uncertainties in measurementsUncertainties in measurements

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decompressorare needed to see this picture.

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Spectral Type vs TemperatureSpectral Type vs Temperature

Note: these relationships are for luminosity class V stars. (See Sec. 15.2 of your text.

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Monday: Bring laptops - We start Part CMonday: Bring laptops - We start Part C

In search of a more accurate way to determine stellar temperatures.

5770 K !!!

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Pyrometer (Stefan-Boltzmann Law in action on Earth)Pyrometer (Stefan-Boltzmann Law in action on Earth)