Exoplanets. II
Sensitivity to Exoplanets
Extrasolar
Planet
Detectability
What Have We Found?
1822 planets in 1132 systems as of 9/8/14
(http://exoplanet.eu/ )
1516 planets + 3359 candidates
(http://exoplanets.org)
• • • • • Detected by radial velocity or astrometry:
Transiting planets:
Detected by microlensing:
Detected by imaging:
Detected by timing:
First Extrasolar Planet:
51 Pegasi b
Radial velocity/ Doppler Shift
Doppler Wobble: Gliese 876
The three planets of Gl 876:
masses = 2.5 MJ, 0.8 MJ, and 7.5
M⊕
Gliese 876
M4V star
3 planets, including the least massive known (0.75 M⊕)
Direct Imaging Example:
HR 8799
Transit Example - Ground
Transit Example - Kepler
Microlensing Example
Extrasolar Planets Orbits
Orbital Eccentricity
Extrasolar Planets Orbits
Extrasolar Planets Orbits
Extrasolar Planets Masses
Planetary Mass Distribution
Extrasolar Planets
Planets are preferentially found around metal-rich stars
- mostly younger than the Sun.
Metallicities updated
Extrasolar Planetary Systems
55 Cancri (G5V): 5 planets
• 1 MU 0.4 AU
• 1 MJ 0.15 AU
• 1 Ms 0.25 AU
• 0.5 MJ 0.8 AU
• 4 MJ 5 AU
Earth-like Exoplanets?
N Update
N = N* fs fp
• N* = 4 x 1011
• fs = 0.2
• fp ~ 1
N = 8 x 1010