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Probing for Puny Planets. Nick Cowan (for Eric Agol) October 19, 2006. Extrasolar Planets. … are planets orbiting other stars. We’ve discovered some 200 of them. They’re mostly in tight orbits (days/weeks) They’re mostly pretty big (Jupiter-sized).
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Probing for Puny Planets Nick Cowan (for Eric Agol) October 19, 2006
Extrasolar Planets • … are planets orbiting other stars. • We’ve discovered some 200 of them. • They’re mostly in tight orbits (days/weeks) • They’re mostly pretty big (Jupiter-sized). • The small (Earth-sized) ones are the ones we’d like to know about. • Small planets are hard to detect.
Transiting Planets • A very small number (10 or so) of the known extrasolar systems happen to be oriented so that the planet passes in front of its host star.
Orbital Resonance • …is like pushing someone on a swing • As long as you always push them at the same point in their swing, they’ll go higher and higher…
Detecting Small Planets • If even a little planet happens to be in an orbital resonance with a giant planet planet, it will cause a noticeable shift in the giant planet’s orbit! • This shift will change the transit time of the giant planet. • If only we had lots of recorded transit for some planet…
HD 209458 b • … was the first transiting extrasolar planet discovered. • Lots of people have looked at this system with Hubble, and their images becomes public a year after they’re taken.
How to Detect a Terrestrial Planet (with current technology!) • Grab all the public HST images of HD 209458. • Construct light curves for loads and loads of transits. • See if the transits are regular like clockwork, or if their timing is a bit off.
What You’ll Do • Retrieve and work with Hubble Space Telescope images! • Learn about “Hot Jupiters”! • See what “Limb Darkening” is all about! • Learn about “Orbital Resonances”! • See Eric get super excited and scribble on his chalk board!