Transcript TPF MMR Agenda

Life in the Milky Way:
Panel Discussion
Wesley A. Traub
Chief 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?
Strategies for answering these might come from this meeting.
Meanwhile, here are the search methods we are using or considering:
- Radial velocity
mass, orbit (~400 discovered)
- Transits
radius, orbit (~700 discovered)
- Gravitational lensing
mass, orbit (snapshot) (~handful)
- Astrometry
mass, orbit (none yet)
- Nulling
exozodiacal brightness
- Direct imaging
brightness, orbit, (~5 discovered);
also atmosphere, surface, rotation,
temperature, water, oxygen, ozone,
carbon dioxide, red edge (land plants),
i.e., signs of life.
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Three Direct Images To Date
Ref.: Fomalhaut, Kalas et al., 2009
HR8799, Marois et al., 2009
also Serabyn & Mawet 2010
Beta Pic, Lagrange et al., 2010
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Exoplanet prospects, near and far
SIM Lite astrometry
5 to 25 pc distant
~70 to 2100 stars
3 to 7 mag
100% of sky
Expect 70 Earths (1/star)
+
TPF-C/O/I direct imaging
Color & spectrum all planets
Signs of life
PLATO transits/seismology
100-400 pc distant
250,000 stars
10 to 13 mag
8% of sky
Expect 400 Earths (1/star)
CoRoT transits/seismology
400 to 2000 pc distant
~40,000 stars
13 to 15 mag
0.01% of sky
Kepler transits/seismology
500 to 2000 pc distant
156,000 stars
14 to 16 mag
0.24% of sky
Expect 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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