8 Exoplanets Worlds Without End Copyright Lynette Cook, used with permission

8 Goals Are there planets around other stars? How do we know? Are they systems like ours? Copyright Lynette Cook, used with permission

8 Copyright – Tyler Nordgren Are there other Earths?

8 Putting it all together Copyright Lynette Cook, used with permission

8 1. Thermal Emission and Spectral lines A star like our Sun has absorption lines. HOT COOL You

8 2. Reflex Motion The Moon doesn’t orbit the Earth. The Earth doesn’t orbit the Sun. What do they do? They each orbit their combined center of mass. X

8 Wobble

8 3. Doppler Shifts Movement towards or away yields Doppler shifts. You X

8 4. Doppler Velocity From Doppler shifts we get a velocity and period.

8 5. Kepler Kepler’s Second Law: Kepler’s Third Law:

8 Result: 51 Pegasi Mayor and Queloz a = AU Copyright Lynette Cook, used with permission

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8 Worlds without End? Known Planets: –In our Solar System: 9 –Outside our Solar System: 133 Known Planetary Systems: –Prior Sept. 1995: 1 (ours) –As of Sept. 2004: 14 Copyright Lynette Cook, used with permission

8 Upsilon Andromedae

8 But Are They Real? Copyright Lynette Cook, used with permission

8 Planet Shadows

8 HD Based on Doppler curve, knew when planet might pass in front of its star. Greg Henry (Tennessee State Univ.)

8 Copyright Lynette Cook, used with permission

8 Savage et al Hubble Space Telescope

8 Hot Jupiters Atmosphere evaporation

8 51 Peg