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Unformatted text preview: 3/31/09 Lecture 20 Dr. Silverstone Astr101 Spring 2009 1 Lecture 20 Announcements Lecture 20 Announcements Reminders: HW #7 (Ch 11) is due Friday Night April 3 (at midnight) Midterm #2 in one week! Tuesday April 7 Bring ScanTron answer sheet, #2 pencil, scientific calculator Review Session? Finish Reading Chapters 12,13, & 14 (Jovian Planets & moons) TEST YOUR CLICKER ! Todays Outline: Review of Current Scores on BlackBoard Surface Temperature and Escaping Gases Chapter 15 Asteroids & Comets Kirkwood Gaps Asteroids & Meteorites Comets & Meteor Showers 3/31/09 Lecture 20 Dr. Silverstone Astr101 Spring 2009 2 Lecture 20 Announcements 2.0 Lecture 20 Announcements 2.0 Reminders: HW #7 (Ch 11) is due Friday Night April 3 (at midnight) Midterm #2 in one week! Tuesday April 7 Bring ScanTron answer sheet, #2 pencil, scientific calculator Review Session? Study for your Midterm! Bring Questions about concepts giving you trouble to Thursdays Class! TEST YOUR CLICKER ! Todays Outline: Review of Current Scores on BlackBoard Surface Temperature and Escaping Gases Chapter 15 Asteroids & Comets Kirkwood Gaps Asteroids & Meteorites Comets & Meteor Showers 3/31/09 Lecture 20 Dr. Silverstone Astr101 Spring 2009 3 Current Scores on BlackBoard Current Scores on BlackBoard Maximum score = 70 (the remaining 30 comes from the Final Exam) Average = 47.6 / 70 = 68% 20% iClicker , 20% Homework , 30% Midterm(s), 30% Final Exam Red = expected # of 77 students, % in the Syllabus: A: 20%, B: 30%, C: 30%, D: 15%, F: 5% 3/31/09 Lecture 20 Dr. Silverstone Astr101 Spring 2009 4 Calculating Surface Temperature Calculating Surface Temperature Luminosity = total energy (over all colors) in all directions Flux = energy through a specific surface area = Luminosity / (4 r 2 ) Stephan Boltzman law (1879): Flux from a Blackbody F = T 4 Luminosity of the Sun L Sun = 4 r Sun 2 T Sun 4 What is the temperature of the Suns light at the distance of the Earths orbit?...
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This note was uploaded on 05/03/2009 for the course ASTR 101 taught by Professor Christiansen during the Spring '08 term at UNC.
 Spring '08
 Christiansen
 Astronomy, Moons

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