midterm3-2-sol-1

midterm3-2-sol-1 - ASTR 100 Midterm 2 Version 2 Solutions...

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ASTR 100 Midterm 2 Version 2 Solutions November 19, 2010 Short Answer, 5 pts each. 1. Explain how astronomers have determined the composition of the Sun. (Note that this is not asking what the composition is, but HOW it was Fgured out.) Then, in a couple sentences, discuss whether this is the composition of the Sun’s core or surface, and why you think so. Astronomers have determined the composition of the Sun by observing the Sun’s absorption spectrum. The absorption lines in its spectrum are created byelementsintheSun’satmosphere absorbing light that is coming out of the Sun’s interior. Astronomers compare the placement of the absorption lines in the Sun’s spectrum to those in a catalog of spectra and then identify the elements absorbing the light. This composition is the composition of the Sun’s surface, because that’s where the gas is that is absorbing the light and causing the absorption lines in the Sun’s spectrum. The gas is the Sun’s core is so dense that it emits a continuous spectrum, so we cannot identify its composition directly. (Also, the gas in the Sun’s core and surface do not mix, because there is no convection in the Sun’s core or radiation zone.) 2. The diagram below shows three spectra (1 - 3). The blue end and red end of the spectra are labeled. Which spectrum is the spectrum of the Sun as the Hubble Space Telescope (in orbit around the Earth above the Earth’s atmosphere) would see it? Which spectrum is the spectrum
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This note was uploaded on 12/15/2010 for the course ASTR 100 taught by Professor Hayes-gehrke during the Fall '06 term at Maryland.

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midterm3-2-sol-1 - ASTR 100 Midterm 2 Version 2 Solutions...

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