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Observed Properties of Multiple - Planet Systems
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Properties of Single Planets (Review of Last Time) Properties of Single Planets (Review of Last Time) Theory: Migration & Planets Tug on Planets Theory: Migration & Planets Tug on Planets Neptune-Mass Planets: First Observations Neptune-Mass Planets: First Observations Multi-Planet Systems: Properties Multi-Planet Systems: Properties Mean-Motion Resonances Mean-Motion Resonances Formation & Evolution Puzzles Formation & Evolution Puzzles Properties of Multi-Planet Systems: Outline of Talk
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Exoplanet Detection Methods Proven Techniques Precise Doppler: 170 Precise Doppler: 170 Transits: 8 Transits: 8 Gravitational lensing: 3 ? Gravitational lensing: 3 ? Direct Imaging: 2 ? Direct Imaging: 2 ? Techniques for the Future Astrometry: Astrometry: Precise Doppler Precise Doppler Kepler Kepler # Planetary Systems
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Doppler Detection of Wobble of Star orbiting common center of mass with planet(s). Doppler Detection of Wobble of Star orbiting common center of mass with planet(s). NASA/JPL 178 Giant Exoplanets Detected Around Sun-Like Stars Review Last Time
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Stars Wobble: Gravitational pull of Planets Doppler Effect of Star Light Spectrum of starlight
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Echelle Spectrometer CCD Echelle Grating Collimator Starlight From Telescope High Resolution ``Echelle” Spectrometer
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Spectrum of Star: Doppler Effect Doppler Precision: 1 m/s v / c ~ 3 x 10 -9 ~ 3 x 10 -9 4096 Pixels Saturn induces 3 m/s in Sun : 0.001 pixel
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Three Telescopes 19 Yrs (6 AU) Lick 8 Yrs (4 AU) 7 Yrs (3.5 AU) Doppler Precision: 3 m s -1 115 Extrasolar Planets 1300 FGKM Nearby Stars Anglo-Aus. Tel. Keck
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Doppler Precision: 1.0 ms -1 Keck HIRES Upgrade (2004) 1 year
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Known Exoplanets Jan 1996
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a = 0 - 5 AU a = 0 - 5 AU M sini = 0.05-15 M JUP M sini = 0.05-15 M JUP Multiple Planets Multiple Planets Nearly half found by: Nearly half found by: Swiss team Harvard teams Harvard teams Texas teams Texas teams 178
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New Planet P = 5.3 yr e = 0.47 2.96 M JUP
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New Planet: P = 1.3 yr e ~ 0.1
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Msini = 32 M Earth Msini = 57 M Earth Msini = 37 M Earth Sub-Saturn Masses: 30 - 100 M Earth Sub-Saturn Masses: Detectable for P < 3 Month Detectable for P < 3 Month
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Giant Planets: Mass Distribution Detection Limit: ~ 0.2 M JUP @ 1 AU Rise toward Rise toward low masses low masses to 1 M SAT to 1 M SAT Sub-Saturn? Sub-Saturn? Review
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Models: Poor Detect- ability Flat Extrapolation: 6% of stars have 6% of stars have planets 3 - 20 AU. planets 3 - 20 AU. Total: 12 % Total: 12 % Inward Migration. Inward Migration. Planets left in place Planets left in place as disk vanishes. as disk vanishes. Rise Prediction: Prediction: Reservoir of Jupiters Reservoir of Jupiters at 5-20 AU at 5-20 AU Log Semimajor Axis Distribution 6.5 % Occurrence
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Future: Gas Giants Orbiting Beyond 5 AU Represents 5 % Represents 5 % of Stars of Stars Orbits: Orbits: Circular or Circular or Eccentric? Eccentric? G0 V
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Orbital Eccentricities = 0.25 = 0.25 Origin of eccent. Origin of eccent. controversial. controversial. (But suggestion later, and talk by Veras & Armitage) Ecc still high Ecc still high Beyond 2.5 AU Beyond 2.5 AU <e>=0.25 Tidal Circ.: a < 0.07 AU a < 0.07 AU
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Super-Earths: 1 - 14 M Earth The Next Domain Earth - Uranus: Earth - Uranus: Gap in Mass: Factor 14 Gap in Mass: Factor 14 Intermediate Masses : Intermediate Masses : Do they Form? Do they Form? Or do planet embryos Or do planet embryos accrete gas ala Neptune ? accrete gas ala Neptune ? If They Form: If They Form: - Terr-like: CO 2 Atm. ? - Terr-like: CO 2 Atm. ? - Neptune-like H&He env ? - Neptune-like H&He env ? Density: 1 or 5 g cm -3 ? Density: 1 or 5 g cm -3 ? Terrestrial Ice & Gas giants Super-Earths?
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and life in the universe
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Too hot Too cold Temp = 0 - 100 C First Search for Habitable Worlds Next Frontier: Will Need an Extraordinary, New Telescope To Detect Earth-Like Planets. NASA...
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NASA’s Effort to: Discover Earths Orbiting other Stars NASA’s Effort to: Discover Earths Orbiting other Stars First Survey for Earths: First Survey for Earths: Occurrence rate. Occurrence rate. d = 1 kpc, No masses d = 1 kpc, No masses Finds Nearby (d< 20 pc) Earths: Finds Nearby (d< 20 pc) Earths: Measures masses and orbits. Measures masses and orbits. Follow-up: IR disks, Doppler, Follow-up: IR disks, Doppler, Imaging planets (TPF, AO) Imaging planets (TPF, AO) Kepler: SIM:
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Observed Properties of Multiple - Planet Systems
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HD 12661 (G0 V) Periodogram P = 5yr
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Weak Interactions 2.5 M J 1.9 M J Possible 6:1 Resonance Gozdziewski & Maciejewski, Lee & Peale HD 12661: 2 - Planet Model RMS=3.4 m/s
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HD 128311 2:1 Resonance Inner Outer Inner Outer Per (d) 458 918 M sini 2.3 3.1 ecc 0.23 0.22 119 212 P c / P b = 2.004 Dynamical Resonance (Laughlin) K0V, 1Gy, 16 pc
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Upsilon Andromedae First multiple-planet system discovered around a regular “main sequence” star in 1999. SFSU First multiple-planet system discovered around a regular “main sequence” star in 1999. SFSU Now have ~ 450 Doppler observations with precision limited by stellar jitter of ~ 7.5m/s Now have ~ 450 Doppler observations with precision limited by stellar jitter of ~ 7.5m/s Upsilon And c & d have significant orbital eccentricities (e = 0.25 & 0.27 ±0.02) Upsilon And c & d have significant orbital eccentricities (e = 0.25 & 0.27 ±0.02) Orbit Eccentricities change during 1000 years. Orbit Eccentricities change during 1000 years. What is the origin of these eccentricities? What is the origin of these eccentricities?
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Mass = 0.62 M JUP 0.65 0.70 0.75 0.80 60 Days
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Upsilon Andromedae : Velocity Residuals P Tp ecc K Msini a (d) (JD-2450000) (deg) (m/s) (M JUP ) (AU) ----------------------------------------------------------------------------- 4.61712 2.01588 0.028 66.7 68.1 0.66 0.059 241.2 160.4765 0.24 252 55.7 1.97 0.828 1318.4 138.3883 0.28 300 62.2 3.84 2.569 ----------------------------------------------------------------------------- RMS = 15.6 m/s N points = 279 omega = 48 deg Circulating Or Librating? e C 0 ?
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0.6 M JUP 2 M JUP 4 M Jup Upsilon Andromedae: Triple Planet System.......... e=0.25 0 ? 0 ? e=0.27 Impulsive Origin of ecc ? (Ford, Rasio, Malhotra)
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Planet-Planet Scattering: Impulsive Origin Of Eccentricites ?
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Upsilon Andromeda: Origin of Eccentricities Initial Eccentricity = 0
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Gliese 876 Real-Time Mean-Motion Resonance and first Super Earth: Star’s Mass = 0.32 M sun Star’s Mass = 0.32 M sun Two Jupiters in 2:1 res. Two Jupiters in 2:1 res.
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GJ 876: Velocities Two-PlanetModel Laughlin et al. 2004 Time Resid
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GL 876 2:1 Mean-Motion Resonance & Apsidal Lock Inner Outer Inner Outer P 30.1 61.0 d Msini 0.56 1.89 M J e 0.27 0.10 Resonance Work: Laughlin & Chambers Lissauer & Rivera Man Hoi Lee & S.Peale
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Gliese 876 2:1 2:1 Mean Motion Resonance Precession Period: 9 yr Man Hoi Lee
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Marcy stopped here, as time ran out. Marcy stopped here, as time ran out.
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GJ 876: Velocities Two-PlanetModel Laughlin et al. 2004
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Velocity Residuals to 2-Planet fit Period = 1.94 d M sin i = 5.9 M Earth For i = 50 deg, M PL = 7.5 M Earth Velocity Lowest Mass Exoplanet to date. Orbital Phase
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3-Planet Fit Rivera & Lissauer
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Gliese 876 Two Jupiters in 2:1 Resonance 7 1/2 Earth-Mass Planet 7 1/2 Earth-masses Excitation of Eccentricity Excitation of Eccentricity Tidal Heating Tidal Heating
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a, M PL, ecc shown 20 multi-planet systems 151 planet-bearing stars 5 Mean-Motion Resonances: Gl 876 (2:1) 55 Cnc (3:1) HD 82943 (2:1) HD 73526 (2:1) HD 128311 (2:1) Proposed M-M Res. : HD 37124 (5:1 ?) HD 12661 (6:1 ?) HD 202206 (6:1 ?) a, M PL, ecc shown 20 multi-planet systems 151 planet-bearing stars 5 Mean-Motion Resonances: Gl 876 (2:1) 55 Cnc (3:1) HD 82943 (2:1) HD 73526 (2:1) HD 128311 (2:1) Proposed M-M Res. : HD 37124 (5:1 ?) HD 12661 (6:1 ?) HD 202206 (6:1 ?) 178 178
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Compare Multi-Planet systems to single- planet systems
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Ups And M sini (M JUP ) Single-Planet Systems Multi-Planet Systems Planet Mass Distributions Neptunes Common Neptunes Common Saturn Paucity Saturn Paucity Explanation? Explanation?
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GJ 876 Single-Planets Multi-Planets Eccentricities: No Sig. Difference;Surprising:Multi-systems should suffer resonances & perturbations
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Summary Planet Mass Distribution: Peaks Below 1 M SAT Planet Mass Distribution: Peaks Below 1 M SAT Semimajor Axis Distrib. Rises toward 5 AU Semimajor Axis Distrib. Rises toward 5 AU Multi-planet Systems common Multi-planet Systems common Mean-Motion Resonances Common Mean-Motion Resonances Common Migration, capture, eccentricity pumping Migration, capture, eccentricity pumping Properties of Multi-Planets not very different Properties of Multi-Planets not very different from single-planet systems: Common processes? from single-planet systems: Common processes?
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GJ 876 Total eccentricity vs Total Planet Mass More mass Higher eccentricity
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GJ 876 Planet Mass Ratio Period Ratio Stability of large Mass ratios Requires wide separation
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GJ 876 Outer planet tends to be more massive. 13 7
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GJ 876
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Single-Planets Multi-Planets MetalicityDependence Same for Single and Multi-planets: High Fe/H Favored.
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GJ 876
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APF Webcam
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Constant gravity environment Constant gravity environment Athermalized optical train Athermalized optical train High efficiency (35%) High efficiency (35%) = 100,000 (for 1 arcsec slit) Passively compensated space-frame Passively compensated space-frame 1 m/s velocity precision 1 m/s velocity precision Cost: $2 million (NASA) Cost: $2 million (NASA) The APF Spectrometer A high resolution spectrometer optimized for ultra-precision radial velocity work for ultra-precision radial velocity work Telescope Beam Designed by Steve Vogt
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What We've Learned Giant Planets in Short Period & Eccentric Orbits Giant Planets in Short Period & Eccentric Orbits Orbital Migration Orbital Migration Eccentricity Excitation Eccentricity Excitation Multiple Planet Systems Multiple Planet Systems Importance of Resonances Importance of Resonances Statistics Statistics Frequency of Giant Planets within ~3 AU Frequency of Giant Planets within ~3 AU Mass-Period Distribution Function Mass-Period Distribution Function Correlations (Stellar Mass & Metallicity, Other Planets) Correlations (Stellar Mass & Metallicity, Other Planets) Artwork courtesy of Sylwia Walerys
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Why did Jupiter stay… Do most giant planets… What limits… Implications for terrestrial planets... New Questions New Questions At 5 AU? At 5 AU? Migrate? Migrate? Migration? Migration? Formation? Formation? In a circular orbit? In a circular orbit? Have eccentric orbits? Have eccentric orbits? Eccentricity growth? Eccentricity growth? Habitability? Habitability? Artwork courtesy of Sylwia Walerys
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