11Explain how knowledge of Stefan-Boltzmannlaw leads to understanding of temperatures andradii of stars.Summarize the circumstances under whichobjects produce thermal (continuous), emissionline, or absorption line spectra.Explain what is meant by the spectralsequence of stars.Learning Goals . . . .Learning Goals . . . .2 How does the Stefan-Boltzmannlaw lead to our understanding oftemperatures 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.3 Explain how knowledge of Stefan-Boltzmann law leads tounderstanding of temperatures and radii of stars.! L = 4"R2#T4Stefan-Boltzmann LawStefan-Boltzmann Law41. Between A and C (large and warm,small and warm), which one willboil water first?2. Between A and B, which one willboil water first?3. Between B and D (large andmedium, small and hot), which onewill boil water first?ABCDCoils of same color have same TemperatureABCD! L " R2T425A BCD! L = 4"R2#T46Applyingto stars! L = 4"R2#T4L4"#T4= R2R =L4"#T4We have waysof finding L(luminosity).7How does the Stefan-Boltzmann law lead to our understanding oftemperatures and radii of stars?8http://www.youtube.com/watch?v=bov9M2gEgcE39 Explain how knowledge of Stefan-Boltzmann law leads to understanding oftemperatures and radii of stars.Summarize the circumstancesunder which objects produce thermal,emission line, or absorption linespectra.Explain what is meant by the spectral sequence of stars.10KirchhoffKirchhoff’’s Lawss Laws11Production of an emission line spectrumProduction of a continuous spectrumIllustrating the geometry needed to vieweach of the kinds of spectra12Where is the Where is the ““cooler, lower-density cloudcooler, lower-density cloud”” in a in astar?star???Core: 17,000,000 K “Surface”: 6,000 K“Absorption Layer”: 4,000 K413Putting filters to practical use:14Putting Kirchhoff’s laws to practical use when observing Helix nebula:1. Absorption2. Emission3. Continuous A. White DwarfB. Diffuse GasC. Distant star behind cooler gas15Summarize the circumstances under which objects produce thermal,emission line, or absorption line spectra.16Explain how knowledge of Stefan-Boltzmann law leads tounderstanding of temperatures and radii of stars.Summarize the circumstances under which objects producethermal (continuous), emission line, or absorption line spectra.Explain what is meant by thespectral sequence of stars.OO BB AA FF GG KK MM L L T T517Universe is full of things that look like stars!Universe is full of things that look like stars!Pluto & Charon18One of these things is not like the others . . . .One of these things is not like the others . . . .19 Explain what is meant by the spectral sequence of stars20 Explain what is meant by the spectral sequence of stars621Cause for confusion:Cause for confusion: what about how the spectra looked what about how the spectra lookeddifferent because of chemical abundances, such as wedifferent because of chemical abundances, such as welearned about in the spectral analysis lab?learned about in the spectral analysis lab?229876543210987654321098765432109876543210987654321098765432109876543210 Explain what is meant by the spectral sequence of starshttp://www.astro.uiuc.edu/~kaler/sow/class-g.html23 Explain what is meant by the spectral sequence of stars24Explain what is meant by the spectral sequence of stars.OO BB AA FF GG KK MM L L T
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