Observed Properties ofObserved Properties of
Multiple - Planet SystemsMultiple - Planet Systems
Properties of Single Planets (Review of Last Time)Properties of Single Planets (Review of Last Time) Theory: Migration & Planets Theory: Migration & Planets TugTug on Planets on Planets Neptune-Mass Planets: First ObservationsNeptune-Mass Planets: First Observations Multi-Planet Systems: PropertiesMulti-Planet Systems: Properties Mean-Motion ResonancesMean-Motion Resonances Formation & Evolution PuzzlesFormation & Evolution Puzzles
Properties ofProperties of
Multi-Planet Systems:Multi-Planet Systems:Outline of TalkOutline of Talk
Exoplanet Detection MethodsExoplanet Detection MethodsProven TechniquesProven TechniquesPrecise Doppler:Precise Doppler: 170170 Transits:Transits: 88Gravitational lensing:Gravitational lensing: 3 ?3 ?Direct Imaging:Direct Imaging: 2 ? 2 ?
Techniques for the FutureTechniques for the Future Astrometry: Astrometry: Precise Doppler Precise Doppler KeplerKepler
# Planetary Systems
Doppler Detection of Doppler Detection of
Wobble of StarWobble of Star orbiting common orbiting common center of mass center of mass with planet(s). with planet(s).
NASA/JPL178 Giant Exoplanets178 Giant ExoplanetsDetected Around Sun-Like StarsDetected Around Sun-Like Stars
ReviewReview
Last TimeLast Time
Stars Wobble: Stars Wobble: Gravitational pull of PlanetsGravitational pull of Planets
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DopplerDopplerEffect of Effect of Star LightStar Light
SpectrumSpectrumof starlightof starlight
Echelle SpectrometerEchelle Spectrometer
CCD
Echelle
Grating
Collimator
StarlightStarlight
From TelescopeFrom Telescope
High Resolution ``Echelle”High Resolution ``Echelle”
SpectrometerSpectrometer
Spectrum of Star:Spectrum of Star:
Doppler EffectDoppler Effect
Doppler Precision: 1 m/sDoppler Precision: 1 m/sv / c ~ 3 x 10v / c ~ 3 x 10-9-9
~ 3 x 10~ 3 x 10-9-9
4096 Pixels
Saturn induces Saturn induces
3 m/s in Sun :3 m/s in Sun :
0.001 pixel0.001 pixel
Three TelescopesThree Telescopes
19 Yrs19 Yrs(6 AU)(6 AU)
LickLick
8 Yrs8 Yrs
(4 AU) 7 Yrs7 Yrs
(3.5 AU)
Doppler Precision: 3 m s-1
115 Extrasolar Planets
1300 FGKM Nearby Stars1300 FGKM Nearby Stars
Anglo-Aus. Tel.Anglo-Aus. Tel.
KeckKeck
Doppler Precision:Doppler Precision: 1.0 ms 1.0 ms-1-1 Keck HIRES Upgrade (2004)Keck HIRES Upgrade (2004)
1 year1 year
Known ExoplanetsKnown ExoplanetsJan 1996Jan 1996
a = 0 - 5 AUa = 0 - 5 AU M sinM sinii = = 0.05-15 M0.05-15 MJUPJUP
Multiple PlanetsMultiple Planets
Nearly half found by:Nearly half found by: Swiss teamSwiss team
Harvard teamsHarvard teams
Texas teamsTexas teams
178178
New PlanetNew Planet
P = 5.3 yrP = 5.3 yr
e = 0.47e = 0.472.96 M2.96 MJUPJUP
New Planet:New Planet:
P = 1.3 yrP = 1.3 yr
e ~ 0.1e ~ 0.1
Msini = 32 MMsini = 32 MEarthEarth
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Msini = 57 MMsini = 57 MEarthEarth
Msini = 37 MMsini = 37 MEarthEarth
Sub-Saturn Masses: 30 - 100 MSub-Saturn Masses: 30 - 100 MEarthEarth
Sub-Saturn Masses:Sub-Saturn Masses:
Detectable for P < 3 MonthDetectable for P < 3 Month
Giant Planets:Giant Planets: Mass Distribution Mass Distribution
Detection Detection Limit:Limit:
~ 0.2 M~ 0.2 MJUP JUP @ 1 @ 1 AUAU
Rise toward Rise toward
low masseslow masses
to 1 Mto 1 MSATSAT
Sub-Sub-Saturn?Saturn?
ReviewReview
Models:Models:
PoorDetect-ability
Flat Extrapolation:Flat Extrapolation:
6% of stars have6% of stars have
planets 3 - 20 AU planets 3 - 20 AU ..
Total: 12 %Total: 12 %
Inward Migration.Inward Migration. Planets left in placePlanets left in place
as disk vanishes .as disk vanishes .
RiseRise
Prediction:Prediction:
Reservoir of Jupiters Reservoir of Jupiters
at 5-20 AUat 5-20 AULogLog
Semimajor Axis Semimajor Axis DistributionDistribution
6.5 % 6.5 %
OccurrenceOccurrence
Future:Future: Gas Giants Orbiting Gas Giants Orbiting
BeyondBeyond 5 AU 5 AU
Represents 5 %Represents 5 %
of Starsof Stars
Orbits:Orbits:
Circular orCircular or
Eccentric?Eccentric?
G0 VG0 V
Orbital EccentricitiesOrbital Eccentricities
<e> = 0.25<e> = 0.25 Origin of eccent.Origin of eccent.
controversial .controversial .(But suggestion(But suggestion
later, and talk bylater, and talk by
Veras & Armitage)Veras & Armitage) Ecc still highEcc still high
BeyondBeyond 2.5 AU 2.5 AU
<e>=0.25<e>=0.25
Tidal Circ.:Tidal Circ.:
a < 0.07 AUa < 0.07 AU
Super-Earths: 1 - 14 MSuper-Earths: 1 - 14 MEarthEarth
The Next DomainThe Next Domain
Earth - Uranus: Earth - Uranus: Gap in Mass: Factor 14Gap in Mass: Factor 14
Intermediate MassesIntermediate Masses:: Do theyDo they Form?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- Terr-like: CO22 Atm. ? Atm. ?
- Neptune-like H&He env ?- Neptune-like H&He env ? Density: Density: 1 or 5 g cm1 or 5 g cm-3 -3 ??
Terrestrial
Ice & Gas giantsIce & Gas giants
Super-Super-
EarthsEarths
??
and and life in the universelife in the universe
Too hot Too coldTemp = 0 - 100 C
First Search for First Search for HabitableHabitable Worlds Worlds
Next Frontier:
Will Need an Extraordinary, New Telescope To Detect Earth-Like Planets.
NASA . . .
NASA’s Effort to:NASA’s Effort to:
Discover EarthsDiscover EarthsOrbiting other StarsOrbiting other Stars
First Survey for Earths:First Survey for Earths: Occurrence rate.Occurrence rate. d = 1 kpc, No massesd = 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)
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SIM:SIM:
Observed Properties ofObserved Properties of
MultipleMultiple - Planet - Planet SystemsSystems
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HD 12661 (G0 V)HD 12661 (G0 V)
PeriodogramPeriodogram
P = 5yrP = 5yr
Weak Interactions2.5 MJ
1.9 MJ
Possible 6:1 ResonanceGozdziewski & Maciejewski,Lee & Peale
HD 12661: 2 - Planet ModelHD 12661: 2 - Planet ModelRMS=3.4 m/sRMS=3.4 m/s
HD 128311HD 128311
2:1 Resonance 2:1 Resonance
Inner OuterInner Outer
Per (d)Per (d) 458 918 458 918
MMsinisini 2.3 3.1 2.3 3.1
ecc 0.23 0.22ecc 0.23 0.22
119 212119 212
PPc c / P/ Pbb = 2.004 = 2.004Dynamical ResonanceDynamical Resonance
(Laughlin)(Laughlin)
K0V, 1Gy, 16 K0V, 1Gy, 16 pcpc
Upsilon Upsilon AndromedaeAndromedae First multiple-planet system discovered around First multiple-planet system discovered around
a regular “main sequence” a regular “main sequence” star in 1999. SFSUstar in 1999. SFSU Now have ~ 450 Doppler observations with Now have ~ 450 Doppler observations with
precision limited by stellar jitter of ~ 7.5m/sprecision limited by stellar jitter of ~ 7.5m/s Upsilon Upsilon And c & d have significant orbital And c & d have significant orbital
eccentricities eccentricities (e = 0.25 & 0.27 (e = 0.25 & 0.27 ±0.02±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?
Mass = 0.62 MMass = 0.62 MJUPJUP
0.65 0.70 0.75 0.800.65 0.70 0.75 0.80
60 Days60 Days
Upsilon AndromedaeUpsilon Andromedae: Velocity Residuals: Velocity Residuals
P Tp ecc K Msini a (d) (JD-2450000) (deg) (m/s) (MJUP) (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 0.8281318.4 138.3883 0.28 300 62.2 3.84 2.569-----------------------------------------------------------------------------RMS = 15.6 m/sN points = 279
omegaomega
= 48 deg= 48 deg
CirculatingCirculating
Or Librating?Or Librating?
eeCC 0 ?0 ?
0.6 M0.6 MJUPJUP
2 M2 MJUPJUP
4 M4 MJupJup
Upsilon Andromedae:Upsilon Andromedae:
Triple Planet SystemTriple Planet System
..
..
..
..
.
..
..
..
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..
..
e=0.25e=0.25
0 ?0 ?
e=0.27e=0.27
ImpulsiveImpulsive
Origin of ecc ?Origin of ecc ?
(Ford, Rasio,(Ford, Rasio,
Malhotra)Malhotra)
Planet-Planet Scattering:Planet-Planet Scattering:
Impulsive OriginImpulsive Origin
Of Eccentricites ?Of Eccentricites ?
Upsilon Andromeda:Upsilon Andromeda:Origin of EccentricitiesOrigin of Eccentricities
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Initial Eccentricity = 0Initial Eccentricity = 0
Gliese 876Gliese 876
Real-Time Real-Time Mean-Motion ResonanceMean-Motion Resonanceand first Super Earth:and first Super Earth:
Star’s Mass = 0.32 MStar’s Mass = 0.32 Msunsun
Two Jupiters in 2:1 res.Two Jupiters in 2:1 res.
GJ 876: VelocitiesGJ 876: Velocities Two-PlanetTwo-Planet
ModelModel
Laughlin et al. 2004TimeTime
ResidResid
GL 876GL 876 2:1 Mean-Motion Resonance2:1 Mean-Motion Resonance
&&Apsidal LockApsidal Lock
Inner OuterInner Outer
PP 30.1 61.0 d 30.1 61.0 d
MsiniMsini 0.56 1.89 M 0.56 1.89 MJJ
ee 0.27 0.10 0.27 0.10
Resonance Work: Laughlin & Chambers Lissauer & Rivera Man Hoi Lee &
S.Peale
Gliese 876Gliese 876
2:12:1
Mean Motion Mean Motion ResonanceResonance
Precession Precession Period: 9 yrPeriod: 9 yr
Man Hoi LeeMan Hoi Lee
Marcy stopped here,Marcy stopped here,
as time ran out.as time ran out.
GJ 876: VelocitiesGJ 876: Velocities Two-PlanetTwo-Planet
ModelModel
Laughlin et al. 2004
Velocity Residuals toVelocity Residuals to
2-Planet fit2-Planet fitPeriod = 1.94 dPeriod = 1.94 d
M sinM sinii = 5.9 M = 5.9 MEarthEarth
For i = 50 deg,For i = 50 deg,
MMPLPL = 7.5 M = 7.5 MEarthEarthVelo
cit
Velo
cit
yy
Lowest MassLowest Mass
Exoplanet to Exoplanet to date.date.Orbital PhaseOrbital Phase
3-Planet Fit3-Planet Fit
Rivera &Rivera &
LissauerLissauer
Gliese 876
Two Jupiters in 2:1 Resonance7 1/2 Earth-Mass Planet
7 1/2 Earth-masses
Excitation of EccentricityExcitation of Eccentricity Tidal HeatingTidal Heating
a, Ma, MPLPL, ecc shown, ecc shown
20 multi-planet 20 multi-planet systemssystems151 planet-bearing 151 planet-bearing starsstars
5 Mean-Motion 5 Mean-Motion Resonances: Resonances: Gl 876 (2:1)Gl 876 (2:1) 55 Cnc (3:1) 55 Cnc (3:1) HD 82943 (2:1) HD 82943 (2:1) HD 73526 (2:1) HD 73526 (2:1) HD 128311 (2:1) HD 128311 (2:1) Proposed M-M Res. :Proposed M-M Res. : HD 37124 (5:1 ?) HD 37124 (5:1 ?) HD 12661 (6:1 ?) HD 12661 (6:1 ?) HD 202206 (6:1 ?) HD 202206 (6:1 ?)
178178
Compare Multi-Planet Compare Multi-Planet systems to single-systems to single-planet systemsplanet systems
Ups AndQuickTime™ and a
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M sini (MM sini (MJUPJUP))
M sini (MM sini (MJUPJUP))
Single-Planet SystemsSingle-Planet Systems
Multi-Planet SystemsMulti-Planet Systems
Planet MassPlanet Mass
DistributionsDistributions
Neptunes CommonNeptunes Common
Saturn PaucitySaturn Paucity
Explanation?Explanation?
GJ 876
Single-PlanetsSingle-Planets
Multi-PlanetsMulti-Planets
Eccentricities:Eccentricities:
No Sig. No Sig.
Difference;Difference;
Surprising:Surprising:
Multi-systemsMulti-systems
should suffershould suffer
resonances &resonances &
perturbationsperturbations
SummarySummary
Planet Mass Distribution: Planet Mass Distribution: Peaks Below 1 MPeaks Below 1 MSATSAT
Semimajor Axis Distrib. Rises toward 5 AUSemimajor Axis Distrib. Rises toward 5 AU Multi-planet Systems commonMulti-planet Systems common Mean-Motion Resonances CommonMean-Motion Resonances Common
Migration, capture, eccentricity pumpingMigration, capture, eccentricity pumping Properties of Multi-Planets not very differentProperties of Multi-Planets not very different
from single-planet systems: Common processes?from single-planet systems: Common processes?
GJ 876
Total eccentricity vs Total Planet MassTotal eccentricity vs Total Planet Mass
More mass Higher eccentricityMore mass Higher eccentricity
GJ 876
Pla
net
Mass R
ati
o
Pla
net
Mass R
ati
o
Period RatioPeriod Ratio
Stability of large Mass ratiosStability of large Mass ratios
Requires wide separationRequires wide separation
GJ 876
Outer planet tends to be more massive.Outer planet tends to be more massive.
131377
GJ 876QuickTime™ and a
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GJ 876QuickTime™ and a
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Single-PlanetsSingle-Planets
Multi-PlanetsMulti-Planets
MetalicityMetalicity
DependenceDependence
Same forSame for
Single and Single and
Multi-planets:Multi-planets:
High Fe/HHigh Fe/H
Favored.Favored.
GJ 876QuickTime™ and a
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APF WebcamAPF Webcam
• Constant gravity environmentConstant gravity environment• Athermalized optical trainAthermalized optical train• High efficiency (35%)High efficiency (35%) = 100,000 (for 1 arcsec slit)= 100,000 (for 1 arcsec slit)• Passively compensated space-framePassively compensated space-frame• 1 m/s velocity precision1 m/s velocity precision• Cost: $2 million (NASA)Cost: $2 million (NASA)
The APF SpectrometerThe APF Spectrometer
A high resolution spectrometer optimizedA high resolution spectrometer optimized for ultra-precision radial velocity workfor ultra-precision radial velocity work
Telescope BeamTelescope Beam
Designed by Steve VogtDesigned by Steve Vogt
What We've LearnedWhat We've LearnedGiant Planets in Short Period & Eccentric Giant Planets in Short Period & Eccentric
OrbitsOrbitsOrbital MigrationOrbital MigrationEccentricity ExcitationEccentricity Excitation
Multiple Planet SystemsMultiple Planet Systems Importance of ResonancesImportance of Resonances
StatisticsStatisticsFrequency of Giant Planets within ~3 AUFrequency of Giant Planets within ~3 AUMass-Period Distribution FunctionMass-Period Distribution FunctionCorrelations (Stellar Mass & Metallicity, Other Correlations (Stellar Mass & Metallicity, Other
Planets)Planets)Artwork courtesy of Sylwia Walerys
Why did Jupiter stay…
Do most giant planets…
What limits…
Implications for terrestrial planets...
New QuestionsNew Questions
• At 5 AU?At 5 AU?
• Migrate? Migrate?
• Migration? Migration?
• Formation?Formation?
• In a circular orbit?In a circular orbit?
• Have eccentric Have eccentric orbits? orbits?
• Eccentricity growth?Eccentricity growth?
• Habitability?Habitability?Artwork courtesy of Sylwia Walerys