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Protoplanetary systems and extrasolar planets Betelgeuse Distance: 197 pc Orion Nebula Distance: 412 pc Orion Constellation Rigel Distance: 260 pc Region of star formation: Orion nebula Distance: 412 pc Apparent magnitude: m = +4.0 Age: 300,000 years old 65″ 60″ Protoplanetary disks in Orion nebula Protoplanetary disks in Orion nebula Size of Solar System The young star Beta Pictoris Distance: d = 19.44 ± 0.05 pc Mass: M = 1.75 M⊙ HST images The young star Beta Pictoris Distance: d = 19.44 ± 0.05 pc Mass: M = 1.75 M⊙ Very Large Telescope image The Solar System Mercury Telluric planets Earth Venus Mars Une planète s’évapore The Solar System Uranus Jupiter Giant gaseous planets Neptune Saturn Une planète s’évapore Solar system Une planète s’évapore Solar system The Trans Neptunian Objects (TNO): Pluto, Quaoar, Eris, and Sedna (diameters 1200-2400 km, dwarf planets) Sedna Eris Pluto Quaoar Neptune To this scale, the Oort Cloud starts about 10 meters from the center of the orbit of Neptune. The Earth’s orbit extends much less than a millimeter from the center. Giordano Bruno (Nola 1548 – Roma 1600) «..l’infinito, universo e mondi innumerabili.» «…un Sole Nero inghiottirà nello spazio il sole, la luna, e tutti pianeti che ruotano intorno al sole" "Ad un corpo di dimensione infinita non può essere attribuito né un centro né un confine” "L'uomo viaggerà nel cosmo e dal cosmo apprenderà il giorno della sua fine” (De l'Infinito Universo et Mondi) “…. le stelle sono infinite e sono soli lontanissimi attorno ai quali girano pianeti e alcuni di questi mondi sono abitati da esseri intelligenti.” Extrasolar planets (as of September 2014) 1.000 904 900 800 Number of planets 700 600 500 400 300 185 200 119 100 0 7 1998 11 20 2000 13 30 2002 25 30 2004 33 29 2006 62 66 2008 Year of discovery 123 132 81 2010 2012 2014 Kepler space observatory (NASA) Launched in 2009 to discover extrasolar planets 51 Pegasi: the first extrasolar planet (1995) Radial velocity of 51 Pegasi Sizes of planets (February 2014) 800 Number of planets 600 400 200 0 Jupiter size Neptune size Super-Earth size Earth size Planets in the dwarf star Gliese 581 Distance: 20.2 ± 0.2 l.y. (6.25 ± 0.05 pc) Planets in dwarf star Gliese 581 ? Kepler-186f: first Earth-size planet In 'Habitable Zone' Main-sequence M1 dwarf star Kepler-186 Distance: 151 ± 18 pc Habitable Zone How extrasolar planets are found • Direct imaging • Radial velocity • Transiting • Gravitational lensing • Transit-timing variation Extrasolar planet M1207b Distance: 52 pc 3-20 times the mass of Jupiter Distance from the star: 7.8 distance Jupiter−Sun Direct imaging Two main difficulties: 1. A small angular separation 2. A huge contrast in luminosity The Sun Jupiter Sun–Jupiter at 4 light years = 4 arcsec Sun–Jupiter at 100 light years = 0.15 arcsec Sun–Earth at 100 light years = 0.03 arcsec Sun–Earth at 330 light years = 0.01 arcsec Star up to 109 times brighter than planet Star up to 109 times brighter than planet One solution: coronograph to block light Main-sequence star HR 8799 Distance: 129 l.y. (39 pc) Mass: M = 1.5 M⊙ Radial velocity Gravitational perturbation induced by Jupiter on Sun Jupiter orbit Period: 11.9 years Distance: 5.2 AU Velocity: 13 km/s Mass: m = 1.9×1027 kg Period: 11.9 years Distance: 0.005 AU Velocity: 12 m/s Mass: M = 2.0×1030 kg Mass center M / m = dm / dM = vm / vM Sun orbit d: distance from mass center v: velocity around mass center Dynamical effects: • Astrometry • Radial velocity Doppler shift Highest resolution today: λ/∆λ = 100,000 ⟾ v = 3 km/s (not enough for Jupiter-Sun system) Jupiter−Sun ⟾ Amplitude = 12.5 m/s Period = 11.9 years Earth−Sun ⟾ Amplitude = 0.1 m/s Period = 1 year Sensitive to short periods and more massive planets ! Occultation or transit Evaporation of Hot-Jupiters Eclipse 4/01/2011 & ISS Credit: Thierry Legault Transit photometry Transit probability Edge-on orbit (i = 90o) Face-on orbit (i = 0o) The first transiting planet: Osiris French mission COROT COROT-7 Period: 0.85 days Mass: < 9 ME Radius:1.58 RE NASA mission Kepler Kepler-10b Period: 0.84 days Mass: 4.5 ME Radius:1.42 RE Kepler light curve for HAT-P-7b Gravitational lensing Albert Einstein T Gravitation (micro)-lensing 32 candidates (September 2014) M = 2.6 (+0.8/−0.6) MJ Semi-major axis: 4.3 (+2.5−0.8) AU Video: http://www3.nd.edu/~bennett/moa53-ogle235/ Transit-timing variation Gravitational perturbation induced by planets Used for the discovery of Neptune (1846) confirmed Newton’s Laws of gravitation Ne n u t p e U u ran s Mathematician Urbain Le Verrier Transit-timing variation Video: http://kepler.nasa.gov/news/nasakeplernews/index.cfm?FuseAction=ShowNews&NewsID=60 Summary (September 2014) 1822 Planets 1137 Planetary systems 467 Multiple planet systems 51 Direct imaging 574 Radial velocity 1147 Transiting 32 Gravitational microlensing a few Transit-timing variation Extrapolation: several hundreds million of Jovian extrasolar planets in the Milky Way with periods of 5 or fewer days Discovered extrasolar planets per year and by detection method (as of September 2014) direct imaging microlensing transit timing radial velocity Present: atmosphere Future: bio signatures Une planète s’évapore