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# afsixteenseventeen - Chapter 16/Chapter17 Chapter Questions...

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Unformatted text preview: Chapter 16/Chapter17 Chapter Questions of the Day Questions What are stars? What are their properties? Who was Annie Jump Cannon? Why was she Who important to the study of stars? important What is stellar spectroscopy? What does it tell us What about a star? about What is the Sun? Why is it important to study this What particular star? particular Parallax of a Star Parallax 1 Distance (parsec) = Parallax Angle (" ) Parallax of a Star Parallax Parallax = 0.2" 1 Distance = Parallax 1 Distance = = 5 parsecs 0.2" Differential Magnitude Differential f − . 5 log 2 2 = 2−1 m m f 1 f m −1 m log 2 =2 f − .5 2 1 f log 1 f 2 f1 f2 f1 f2 m −1 m =2 2.5 = 10 m2 − 1 m 2.5 = . 5m2 2 −1 m Differential Magnitude Differential Two stars have a magnitude of 7 and 3. How Two much brighter is the star with a magnitude of 3 than the star with a magnitude of 7? than m1 m f1 f2 f1 f2 f1 f2 2 = 3 = 7 = 2 . 5m2 = 2 . 57 ≈X 40 − m1 − 3 Distance Modulus Distance m2 = m m1 = M f2 f1 Luminosity (L) = 4 π2 d L = 4π (10 parsec ) 2 2 f − . 5 log 2 f 1 = 2 − 1 m m Distance Modulus L 2 4d − . 5 log 2 L 4 (10 ) 2 π π 2 = m− M 10 − . 5 log 2 m− M = d 10 − log 5 = m− M d d 5 log = m− M 10 d M + log 5 = m 10 Distance Modulus Distance A star has a absolute magnitude of -5 and a star distance of 1000 parsecs. What is the magnitude of the star as view from Earth? magnitude M =5 − d= 1000 pc d M + log 5 10 pc = m 1000 pc − + log 5 5 = m 10 pc − + log( 100 ) 5 5 −+ 5 10 = m 5= m = m Fig.16.08a Fig.16.08a Fig.16.08b Fig.16.08b Fig.16.09 Fig.16.09 Annie Jump Cannon Annie 1863 – 1941 A.D. Born in Delaware, Born grew up in Dover, Delaware. Delaware. Entered Wellsley Entered College College http://astro.wsu.edu/worthey/astro/html/im­women/04­cannon.jpg Annie Jump Cannon’s Work Annie Worked under Edward C. Pickering at Worked Harvard University to classify spectra of stars stars 1911 - 1914: Created the Henry Draper 1911 Catalogue 1918: Doctorate Degree 1914: Honorary in the Royal Astronomical 1914: Society Society Spectral Types Spectral http://blueox.uoregon.edu/~courses/BrauImages/Chap17/FG17_010.jpg Fig.16.18 Fig.16.18 Fig.16.19 Fig.16.19 Mass – Luminosity A star has a mass of 5M, how much brighter is how this star than the Sun? this M =Θ 5M 3.5 L M = L Θ Θ M 3.5 5MΘ L = LΘ Θ M L = 280 LΘ What is the Sun? What Our nearest star. The center of our solar system. The main engine for all the heat produced in The the solar system. the http://spaceflightnow.com/news/n0211/04soho/sun.jpg What are the properties of the sun? What Distance: 1.49 X 108 km = 1 A.U. km Size: 1.4 X 106 meter = 0.5° Mass: 2 X 1030 kg Density: 1.4 g/cm3 Distance to the Sun Distance Aristotle was the first person to consider the Aristotle problem. But Kepler was the first to obtain a precise measurement. Recent measurements use radar bouncing Recent off other planets to obtain more precise measurements. measurements. Size of the Sun Size Aristarchus was the first to consider the size of the Aristarchus Sun. The modern method involves the angle of the light The rays. rays. If the Earth were the size of a penny, 150 Earths If would fit across the face of the sun. would The Mass of the Sun The Newton was the first person to find Newton accurately the mass of the sun with his theory of gravitation. theory 30,000X more massive than the Earth. The Density of the Sun The The density is simple calculation of the The mass over the volume. mass The density is only 40 percent higher than The water suggesting a gaseous composition. water The Layers of a Star The Core Radiative Zone Convective Zone Photosphere Chromosphere Corona http://www.conceptdraw.com/samples/samplestour/Proton/Proton.gif Proton-Proton Chain Proton-Proton Sun Prominence Sun http://www.uniba.sk/~ago/pics/sun/1907anim.gif Sun Flare Sun http://msowww.anu.edu.au/msovc/displays/images/sun­flare.jpg Sunspot Cycle Sunspot http://www.hao.ucar.edu/public/education/sp/images/sunspotn.2.jpg Homework 8 Homework What is the luminosity of the Sun? What is the luminosity What of a O type star? And what the luminosity of the K type star? How do they compare to the luminosity of the Sun? And how much heavier is the O than the K type star? And Two stars have magnitudes of 4 and 9 respectively. How Two much brighter is the star with magnitude 4 than the star with magnitude 9? If these two star were the same absolute magnitude (-4), how much further is the star with apparent magnitude of 9 than the star with the apparent magnitude of 4? magnitude Page 391, CQ 3, 12 Describe the different layers of the Sun via their respective Describe temperatures and pressures. ...
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## This note was uploaded on 12/04/2011 for the course AST 1004 taught by Professor Howard during the Fall '09 term at Broward College.

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