observed properties of multiple - planet systems

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