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?