Extrasolar Planets: Past, Present, and Future
Extrasolar Planets: Past, Present, and Future
The Formation of Planetary Systems
Heretic’s Approach to Solar System
FormationFForm
Alan P. BossCarnegie Institution of Washington
A Decade of Extrasolar Planets Around Normal StarsSpace Telescope Science Institute, Baltimore, Maryland
May 2, 2005
The President’s Vision for U.S.Space Exploration (January 2004)
B. Space Exploration Beyond Low Earth Orbit [Mars and other destinations]: * Conduct advanced telescope searches for Earth-like planets and habitable environments around other stars
Charbonneau et al., 2000HD 209458b
Microlensing detection with Warsaw 1.3m telescope, Las Campanas - 2004
Secondary eclipse of a hot Jupiter by its host star
Spitzer Space Telescope - first direct detection of a planet’s light - 2005
GQ Lup b – 1 Myr-old gas giant planet at 100 AU? (Neuhauser et al. 2005)
brown dwarfs
gas giant planets
Extrasolar Planet Discovery Space
IAU Working Group on Extrasolar Planets
Groupe de Travail sur les planètes extra-solaires
Members of Working Group (2003-2006)
Chair (and Web Page Master): Alan BossMembers: Paul Butler, William Hubbard, Philip Ianna, Martin Kürster, Jack Lissauer, Michel Mayor, Karen Meech, Francois Mignard, Alan Penny, Andreas Quirrenbach, Jill Tarter, Alfred Vidal-Madjar
Charge
The WGESP is charged with acting as a focal point for research on extrasolar planets and organizing IAU activities in the field, including reviewing techniques and maintaining a list of identified planets. The details of the Terms of Reference are available.
Definition of a "planet"
The WGESP has developed a Working Definition of a "planet", subject to change as we learn more about the population of very low mass companions.
List of Planets
The WGESP has developed a Working List of extrasolar planet candidates, subject to revision. In most cases, the orbital inclination of these objects is not yet determined, which is why most should still be considered candidate planets.
http://www.dtm.ciw.edu/boss/iauindex.html
2004
(2004)
low Zhigh Z
metallicity-period correlation
Highest Metallicities Correlation: Migration or Formation?
* Higher metallicity higher opacity hotter disk midplane higher sound speed (cs ) thicker disk (h) higher disk kinematic viscosity (cs h) shorter time scale for Type II inward migration more short period giant planets
* Uncertain magnitude of migration effect, but goes in the right direction to explain the correlation
* Migration consistent with absence of short-period giants in low-metallicity globular cluster 47 Tuc
* Migration consistent with long-period pulsar giant planet in M4 globular cluster (1/30 solar [Fe/H])
Discovery space with latest discoveries addedDiscovery space with Neptune-mass planets
prior lowest m sin i
Neptune-mass, but what composition?
[Need to discover 10 or more so that at least one will transit its star]
-mass
Discovery space with latest discoveries addedDiscovery space with Neptune-mass planets and their siblings
Mu Ara
55 Cnc
G. W. Wetherill, 1996, Icarus, 119, 219-238.
1 Earth mass
Assuming surface density proportional to 1/radius, rock surface density of 9.3 g cm -2 at 1 AU should be increased by a factor of about 7 to account for rock/ice surface density needed at 5 AU of 25 g cm-2 to form Jupiter by core accretion (Inaba et al. 2003)
3 Earth masses
Since mass of the terrestrial planets is roughly proportional to the surface density of solids, raising the solid surface density by a factor of about 7 should result in the formation of rocky planets with masses as high as about 21 Earth masses
Habitable Planets per SystemChambers 2003
[defined as terrestrial planets with masses greater that 1/3 that of Earth and Earth-like orbits]
• Normal Jupiter and Saturn
• Jupiter only, mass x 3
• Jupiter only, eccentricity = 0.4
• Jupiter & Saturn, both mass x 3
• Jupiter normal, Saturn mass x 3
• Jupiter & Saturn, both mass/3
• 1.0 0.6 0.7
• 0.8 0.5 0.7
• 0.1 0.2 0.4
• 0.0 0.0 0.0
• 0.3 0.6 0.4
• 0.8 0.9 0.9
Giant Planet System Configuration:
Giant Planet Formation Time:
0 Myr 3Myr 10Myr
KNASA’s Kepler Mission
• Salient Features– 3 parallel Michelson Stellar Interferometers– 10 meter baseline– Visible wavelength– Launch Vehicle: Space Shuttle or EELV– Earth-trailing solar orbit– 5 year mission life with 10 year goal– SIM is a JPL, Caltech, Lockheed Martin,
NGST, and SIM Science Team partnership
Space Interferometry Mission
• Science– Perform a search for other planetary systems by surveying 2000 nearby stars for astrometric
signatures of planetary companions
– Survey a sample of 200 nearby stars for orbiting planets down to terrestrial-type masses
– Improve best current catalog of star positions by >100x and extend to fainter stars to allow extension of stellar knowledge to include our entire galaxy
– Study dynamics and evolution of stars and star clusters in our galaxy to understand how our galaxy was formed and how it will evolve.
– Calibrate luminosities of important stars and cosmological distance indicators to improve our understanding of stellar processes and to measure precise distance in the distant universe
NASA’s Space Interferometry Mission
Discovery space for extrasolar planetsby ground-based Doppler spectroscopy and by space-based astrometry (SIM)
TPF Coronagraph
NASA’s Coronagraphic Terrestrial Planet Finder Mission
TPF Interferometer
Earth as seen by TES onMars Global Surveyor
Terrestrial Planet Imager?