Extrasolar Planets: Ushering in the Era of Comparative Exoplanetology A. Sozzetti INAF Osservatorio Astrofisico di Torino
Detection/Characterization Detection (Visible): - Doppler spectroscopy (95%) - Transit photometry (20%) - Gravitational microlensing (2%) - Pulsar/pulsation timing (1.5%) - imaging (1.5%) Characterization (Visible/IR): - Transit timing - Transmission spectroscopy - Rossiter-McLaughlin effect - Reflected light - Infrared emission 986 Exoplanets known today, in 750 systems 168 in multiple-planet planet systems
The Historical Perspective
Comparative Exoplanetology Orbital elements, mass distributions, multiplicity Correlations between planetary parameters and between planet characteristics and frequencies and the properties of the stellar hosts Internal structure, atmospheric composition and circulation Putting our Solar System in Context!
Direct Imaging: A Family Portrait 2M1207 DH Tau AB Pic SCR1845 CHXR 73 GJ 758 CT Cha 1RXJS609 GQ Lup Wide orbitpmcs: -lowmass KM stars -q = 0.02 0.2 or > 200 AU CloserPMCs: - A4V-A5V massive primaries -q < 0.005 ; = 8-120 AU -CS Disksignatures Fomalhaut Hr8799 Beta Pic Ref: Chauvin et al. 04; Itohet al. 05; Chauvin et al. 05; Biller et al. 05; Luhmanet al. 06; Thalmannet al. 09; Lafrenièreet al. 08; Neuhauseret al. 05; Schmidt et al. 09; Lagrange et al. 10; Kalaset al. 08; Maroiset al. 08,10...
Direct Imaging: Companion Nature? PlanetSingle-bandphotometry Stellar properties: d & age Evolutionarymodels(Luminosity-Mass). βpictorisb, J = 10.6+-0.3 mag,. 12 Myr@ 19.3 pc,. Mass = 7 8 M jup ( Hot-Start models) > However, uncertainties in the model predictions > Dependence: formation mechanisms, gas accretion shock & initial conditions Marley et al. 07; Mordasiniet al. 12 Field Rotation Bonnefoy et al. 12
Precision RVs: Pushing the Mass Limits Deuterium-burning limit HD 114762b Gap? Alpha CenBb
Habitable Low-Mass Planets?
αcen Bb: The First Earth-(minimum)mass Planet 460 RVs!
The Stellar Noise Challenge
Planetary Systems: Emerging Properties Second planet detection rate 17%, including trends > 30% >20 RV systems with at least three detected planets, and up to 7! Great dynamical diversity (hierarchical systems, secular interactions, mean-motion motion resonances) Inferences on the likelihood of formation and survival of rocky planets in the Habitable Zone Different orbital elements distribution functions Differences in distributions for low-mass systems and systems with gas giants Different behaviour of f p vs. M * and [Fe/H] in single- and multiple-planet planet systems
The Planet Host Star Connection Johnson et al. 2010 Sozzetti et al. 2009 Critical tests of competing giant planet formation models
Transiting Planets: A Treasure Trove Learn about the history of planet migration Learn about the architecture of multiple systems Learn about the physical structure and composition of exoplanets Learn about the structure, chemistry, and dynamics of atmospheres Tens of ground-based surveys, two highly successful space projects
Measuring Spin-Orbit Alignment Ohta, Taruya, & Suto (2005); Gaudi & Winn (2007)
R-M M Effect Measurements: Status Spin-orbit angles have been measured for 35+ exoplanets Many have highly tilted orbits, some are retrograde Tilted orbits are especially common for hot (massive) stars Disk migration cannot be the whole story for hot Jupiters Migration via few-body dynamics? The tradition of exoplanetary surprises continues Even close binary stars can be misaligned!
The Kepler Revolution 3558 78
Multiple-Planet Candidate Systems 100s of flat systems, the vast majority with small radii
Exoplanets Interiors and Atmospheres THEORETICAL INPUT - internal properties - structure and heat content - atmospheric properties Burrows et al. 2007 OBSERVABLES Evolutionary properties as a function of irradiation conditions and orbital distance: - mass, - radius, - temperature, - age, - emergent spectrum, composition Burrows 2005
The Mass-Radius Relationship
Transits Allow Studies of the Atmospheres That Are Not (Yet) Possible for Non-Transiting Planets Secondary Eclipse See thermal radiation and reflected light from planet disappear and reappear Transit See radiation from star transmitted through the planet s atmosphere
Phase Lightcurves HAT-P7b observed by Kepler (Borucki et al, 2010)
Swain et al., 2008; Madhu & Seager, 2009; Danielski et al., 2013; Beaulieu et al., 2010; XCIX Burrows Congresso et al., SIF 2011; Deming et al., 2013; Tinetti et al., 2010; Crouzet SISSA-Trieste, et al., 272012 Sep 2013
GJ 1214b A cool Super-Earth Around an M4.5 dwarf
The Future: Comparative Planetology Observations Space-borne transit surveys (Kepler, TESS, PLATO): frequency of terrestrial habitable planets around G-K G K dwarfs, contributions from ground-based experiments (APACHE, NGTS) for M dwarf samples SPHERE/GPI, ELTs,, JWST, coronagraphs/interferometers and other IR telescopes in space (EChO( EChO): characterization of giant planets atmospheres and search for bio-markers on Earth-sized planets around nearby stars Doppler surveys (HARPS/-N,ESPRESSO), astrometry (Gaia): very low masses, very long periods, wider ranges of the hosts spectral types and ages, characterization of multiple systems. Theory Self-consistent modeling of formation and migration processes, and improved predictions (correlations, population synthesis) 3-d d modeling of realistic disk environment Probabilistic vs. deterministic approach Better input physics for planet interiors and atmospheres