life in the milky way: panel discussion
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Life in the Milky Way:Panel Discussion
Wesley A. TraubChief Scientist, NASA’s Exoplanet Exploration Program
Jet Propulsion Laboratory,California Institute of Technology
Ozma 50 Workshop, Green Bank, West Virginia
13 Sept. 2010
Our Big Questions for Exoplanets• What kind of signs of life should we be looking for? • Where and how should we look?• What is our strategy for finding signs of life beyond the Solar System?
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Three Direct Images To Date
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Ref.: Fomalhaut, Kalas et al., 2009HR8799, Marois et al., 2009 also Serabyn & Mawet 2010Beta Pic, Lagrange et al., 2010
Exoplanet prospects, near and far
Kepler transits/seismology 500 to 2000 pc distant
156,000 stars14 to 16 mag0.24% of sky
Expect 400 Earths (1/star)
CoRoT transits/seismology 400 to 2000 pc distant
~40,000 stars13 to 15 mag0.01% of sky
SIM Lite astrometry 5 to 25 pc distant~70 to 2100 stars
3 to 7 mag100% of sky
Expect 70 Earths (1/star)
+TPF-C/O/I direct imaging
Color & spectrum all planetsSigns of life
PLATO transits/seismology 100-400 pc distant
250,000 stars10 to 13 mag
8% of skyExpect 400 Earths (1/star)
WFIRST gravitational microlensing 1000 to 10,000 pc distant
Prospects for finding and characterizing exoplanets
• Current missions: CoRoT and Kepler for transits
- Telling us frequency of terrestrial planets, from close-in to habitable zones
• Also: Spitzer (warm) and HST
- Giving us transit visible and infrared spectra of giant planets
• Planned missions: JWST
- Possible transit spectra of super-Earth planets
• Recommended mission: WFIRST for exoplanets (and dark energy)
- Gravitational lensing gives mass and snapshot of orbit
• Future possibility: Exoplanet mission
- To be decided around mid-decade, and launched in 2020s,
could be coronagraph imager for exoplanet discovery and characterization
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