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The slides in this collection are all related and should be useful in preparing a presentation on SIM PlanetQuest. Note, however, that there is some redundancy in the collection to allow users to choose slides best suited to their needs.

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Studying Planets – Challenges to Overcome

Planets are faint- Much smaller than stars- emit only the star’s reflected light- high sensitivity of large telescopes is needed

Planets are close to their much brighter star- looking for a firefly in the bright beam of a light

house- high angular resolution is needed to separate the

planet from the star

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Planetary Systems: Questions

• Statistics of planetary systems

– How common are planetary systems?

– Are certain star types favored?

– What is the distribution of planetary systems in the Galaxy?

• Characterizing planetary systems

– What are the orbit radii?

– Are the orbits circular or eccentric?

– Are multiple-planet systems common?

• For multiple planet systems

– What is the typical mass distribution of planets in a system?

– What is the typical radius distribution?

– Are the orbits co-planar?

• Must have astrometry to answer this

– Are the planets stable?

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Planet Detection - Search Regimes for SIM

• Jupiter-mass planets

– Signature is ± 5 as at 1 kpc

– Very large number of available targets

• Intermediate mass range: 2 - 20 Earth masses

– Massive terrestrial planets

– Detectable to many 10s of pc

– SIM can survey a large number of stars for planets less massive than Jupiter

• Earth-like planets

– The most challenging science for SIM

– 1 Earth mass at 1 AU -> ± 0.3 as signature at 10 pc

– Earths detectable only out to a few pc

– Orbit parameters only for the closest systems

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To find life on other planets, first we need to find planets

“Naked Eye” planets

Telescope (1781)

Predicted by Newtonian Mechanics (1846)

Intensive telescope search (1930) - based on incorrect prediction!

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Astrometric Planet Detection: What do we derive from SIM measurements?

Astrometry can measure all of theorbital parameters of all planets.

Orbit parameter Planet PropertyMass Atmosphere?Semi-major axis TemperatureEccentricity Variation of tempOrbit Inclination Coplanar planets?Period

Sun’s reflex motion (Jupiter) ~500 µasSun’s motion from the Earth ~0.3 µas

1A.U. ~ 150,000,000 km

~80 A.U.

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A star will wobble because it orbits a common center of mass with its companion planets

There is more wobble when the companion planet is massive and close to the central star. Groundbased observers measure the Doppler shift. SIM will measure the positional wobble. Doppler shift or a well-determined stellar mass is necessary to determine the true orbit(s) and planet mass(es).

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Many “exoplanets” have been found by measuring the Doppler shift of starlight

First discovery of a planet around a “normal” star (1995)But these are large planets (1 Jupiter Mass = 318 Earth masses) AND many are very close to their central stars. The masses listed are lower limits.

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Where is the most interesting search volume?

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Search for Terrestrial Planets

• SIM adds direct information on masses and orbits for fuller characterization of planets from EarthsJupiters

• SIM planet search program has a strong “terrestrial” planets component balanced by a “broad” survey of 2000 stars of Uranus mass planets The nominal SIM deep planet search program occupies ~17% of SIM time, and can search ~250 stars @ 50 2D visits over 5 years. (or 125 stars @ 100 2D visits or 60 stars @ 200 visits…)– 50 2D visits => ~3 Mearth for 1AU orbit around the Sun

@ 10pc

• The exact observational program will be modified according to best available data at the time, e.g RV on individual stars and on the value of earth from the Kepler mission. (Just as TPF-C’s plan will be modified according to best available knowledge from, e.g. SIM)

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Search for Terrestrial Planets

• Blue, all terrestrial size planets. • Green/Yellow Habitable zones around 1&4 Lsun• Sample size 60~250 stars depending on earth in habitable zone (from COROT/Kepler)

SIM 5yr 200 visits60 stars

Habitable Zone1 L(sun) 4L(sun)Terrestrial sized

planets

(18 pc)

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Planet Mass I (Planet and Star Orbit)

• The planet and star orbit around their common center of mass.– The orbits are mirror images of each other, the planet orbit is ~100,000

times larger.– The mass of the planet is deduced by measuring the motion of the star.

(the mass of the star is measured by watching the planet

– MPlanet = Mstar*Rstar/RPlanet

• SIM measures Rplanet by using Kepler’s 3rd law, from the period of the planet and the mass of the star.

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Planet mass sensitivity vs distance

Best 240 targets are all within 30 pc

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False-alarm probability (FAP)

Choose detection threshold for 1% FAP

Gaussian noise has power at all frequencies: more frequencies searched → more false alarms

FAP at a given detection

threshold is the probability that a noise peak could

exceed the threshold

Monte Carlo of peak periodogram power for 100,000 realizations of Gaussian noise

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Finding Planets Indirectly

• Gravitational Effects on Parent Star

– Radial Velocity Changes

• Favors large planets in close to star

• Independent of distance

– Positional Wobble (Astrometry)

• Favors large planets far from star

• Angular displacement decreases with distance

• SIM’s technique

• Effect of Planet on Star’s Brightness

– Transits of edge-on systems

• Small fraction of a percent for a few hours (10-5 for an Earth)

– Gravitational Lensing

• Planetary companion of lensing star affects magnification of background star by few percent for a few hours

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Planetary Gravitational Lensing

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An Important Example of Using Astrometry• Deduce planets orbiting nearby stars

• Motion of our sun (1990-2020) due to all planets in our solar system as viewed from 10 parsec (a little more than 30 light years) away

Scales are ±0.001 arc sec= ± 1 milli arc second= ± 1000 micro arc sec~ ± 5 nano-radian

Motion of star’s optical center is a few thousand micro arc seconds (μas)

SIM could measure this motion with an accuracy of about 1 μas (~5 pico-radian)

(quite a bit thinner than the line plotted here)

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One Jupiter mass (1 MJ)

corresponds to 318 Earth masses.

Exoplanets Found by Doppler Shift of Starlight

SIM will eliminate orbit inclination ambiguity of radial velocity method and detect smaller planets in longer period orbits

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NEWSScientists discover first of a new class of extrasolar planets

“The wobble effect”: our

Solar System as seen at 10 pc distance

• 1 tick mark = 200 µas• SIM accuracy = 1 µas (single meas.)• Sun-Jupiter wobble = 500 µas • Sun-Earth wobble = 0.3 µas

SIM Simulation:

detecting a planetary orbit with a series of 2-D

measurements

Principle of Astrometric Planet Detection

QuickTime™ and aCinepak decompressor

are needed to see this picture.

1000 µas

1000µas

How Much Wobble?

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Astrometric Planet Detection:What do we derive from SIM measurements?

1A.U. ~ 150,000,000 km

~80 A.U.

Astrometry can measure all of theorbital parameters of all planets.

Orbit parameter Planet PropertyMass Atmosphere?Semimajor axis TemperatureEccentricity Variation of tempOrbit Inclination Coplanar planets?Period

Sun’s reflex motion (Jupiter) ~500 µasSun’s motion from the Earth ~0.3 µas

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What are the SIM Planet-Finding Plans?

• The SIM planet science program has 3 components.

• Searching ~200 nearby stars for terrestrial planets, in its Deep Search at (1 µas).

• Searching ~ 2000 stars in a Broad Survey at lower but still extremely high accuracy (4 µas) to study planetary systems throughout this part of the galaxy.

• Studying the birth of planetary systems around Young Stars so we can understand how planetary systems evolve.

– Do multiple Jupiters form and only a few or none survive during the birth of a star/planetary system?

– Is orbital migration caused primarily by Planet-Planet interaction or by Disk-planet interaction?

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Masses and Orbits of Planets SIM Can Detect

Planetary systems inducing low radial velocities (<10m/s) in their central star can be detected through the astrometric displacement of the parent star.

Systems accessible only with SIM.

SIM will be able to detect planets of a few Earth masses around nearby stars.

Ground based astrometric techniques.

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1

10

100

0.1 0.3 1.0 3.2 10.0 31.6100.0316.21,000.03,162.210,000.031,622.0

Planetary Mass (Earths) .

Number of Detected Planets

E JS

Masses of 104 known planets

UNV

Deep Search for Terrestrial Planets

• Ground-based radial velocity technique detects planets above a Saturn mass

• SIM will detect planets down to a few Earth masses and measure their masses

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But What is a Habitable Planet?

• Not too big • Not too small

• Not too hot or too cold

A good planet is:

SIM can find planets similar in mass to Earth, at the “right distance” from their parent stars

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Broad Survey of Planetary Systems

Out of 100 planetary systems discovered to-date, only one resembles our solar system

So:

• Is our solar system normal or unusual?

• Are planets more common around sun-like stars?

• What are the ‘architectures’ of other planetary systems

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Planets around Young Stars

• How do planetary systems evolve?

• Is the evolution conducive to the formation of Earth-like planets in stable orbits?

• Do multiple Jupiters form and only a few (or none) survive?

SIM will:• Search for Jupiter-mass planets

around young stars – Pick stars with a range of

ages• Measure the ages and

‘evolutionary state’ of young stars– Need precise distances and

companion orbits

The “Close” Candidates

HST Fine Guidance Sensors

FGS-TRANS

NICMOS Discoveries

GJ 54 AB

130 mas

mid-M

2 yr

Binary #2

430 mas

late-M

13 yr

Binary #3

130 mas

mid-M

2 yr

Binary #4

3 arcsec

early-L

… long

Binary #5

80 mas mid-L 2 yr

MLR of VLMs

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Primary SIM Targets

• 250 A, F, G, K, M dwarfs within ~15 pc

– Doppler Recon. @ 1 m s-1

Jupiters & Saturns within 5 AU

– SIM: 30 obs. during 5 yr (1 as)

3 MEarth @ 0.5 - 1.5 AU

• 6 K-giant reference stars @ 0.5 - 1 kpc – Located within 1 deg of each target– Doppler vetting for binaries @ 25 m/s

5 5

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Radial Velocity Planet Searches

Detection Detection Limit:Limit:

~ 0.2 M~ 0.2 MJUP JUP @ 1 @ 1 AUAU

15 - 20 M15 - 20 Mearthearth

Gl 436Gl 436 55 Cnc d55 Cnc d AraAra

RV Limitations:RV Limitations: Only a < 0.1 AUOnly a < 0.1 AU M > 10 MM > 10 Mearthearth

( Butler et al. McArthur ( Butler et al. McArthur et al., Santos et al. )et al., Santos et al. )

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Can RV Detect Rocky Planets at 1 AU ?

Benchmark: 1 Earth Mass at 1 AU.

RV Amplitude: K = 0.09 m/s

RV Errors: = 1.0 m/s

S/N ~ K / ~ 0.1

RV Cannot Find

Earths Anywhere Near HZ

(Even with 1 m/s) Exception: M DwarfsException: M Dwarfs

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Nominal SIM Discovery Space

Unique SIM Domain:

3 - 30 MEARTH

Near Habitable Zones

•Unambiguous Mass

•Co-planarity of orbits in

multi-planet systems

• Orbital: a, P, e

SIMDomain

MASS(MEarth )

1 M1 Mearth earth @ 1 AU for d= 1 pc @ 1 AU for d= 1 pc ==> 3 ==> 3 microarcsecmicroarcsec

......

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Democritus:Pre-Socratic Greek philosopher

(460 - 370 BC).

“There are innumerable worlds of different sizes. These worlds are at irregular distances, more in one direction and less in another, and some are flourishing, others declining. Here they come into being, there they die, and they are destroyed by collision with one another. Some of the worlds have no animal or vegetable life nor any water.”

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PoorDetect-ability

Doppler Survey of 1330 Nearby Sun-like Stars

Extrapolation: 6% of stars

have giant planets beyond 3 AU

Armitage, Livio, Lubow, Pringle Armitage, Livio, Lubow, Pringle

et al. 2002et al. 2002

Trilling, Benz, Lunine 2002Trilling, Benz, Lunine 2002

Model:Inward Migration:Planets left behindas disk vanishes

Rise?Rise?

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Planet – Metallicity Correlation

Fischer & Valenti 2005

Abundance

Analysis of all 1000

stars:

SpectralSpectral

SynthesisSynthesis

Valenti & Fischer 2005

1.61.6

PPplanetplanet ~ ~ ((NNFeFe

/ N/ NHH))

Fe/HFe/H

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Models of Protoplanetary Disks of Gas & Dust

TheoreticalPlanet-Formation:

Dust Growth pebbles/rocks Grav. Runaway Gas Accretion

Migration & Interactions

Formation of Planetary Systems:

ObservationsObservations mm-wave dust emission IR Excess/Spectra & SEDs HST Imaging

MDISK = 10-100 MJUP

Disk Lifetime ~ 3 Myr

The Solar System Paradigm

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Multi-Planet Interactions

Levison, Lissauer, Duncan1998

100 Planet “Embryos” (~MEarth)

Scatter, Collide, Stick, Accrete Gas

Chaos

After 21.5 Myr

After 30 Myr

Lone Close-in,Lone Close-in,

Jupiter inJupiter in

Eccentric Orbit.Eccentric Orbit.

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Levison, Lissauer, Duncan 1998

Size Planet mass (in M earth ) above each

planet.

Peri - Apo of

orbit

AUAU

-- -- --Rocky Planets willRocky Planets will

Outnumber jupiters.Outnumber jupiters.

Monte Carlo Examples of Planetary Systems

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Low-Precision Planet Search

• 400 AFGKM stars at 10-30 pc– SIM precision: 4 as– Use “SIM GRID” (not nearby Ref Stars)– Doppler Recon. at 1 m/s

==> Jupiters and Saturns within 5 AU

4 as @ 30 pc reveals:

30 Mearth at 1 AU

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Error bars are 1 uas

SIM: 3 Earth-Mass Planets

d = 5pc

precision 1 microarcsec

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61 Cygni A

Exp. Error• Photons• Angle

sep.• Planet

jitter

Failure Prob.

1o

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Typical M Dwarf Companion

Eliminate Companions:

25 m/s RV Precision

RV Vetting of Reference Stars

Planetsaround K giantsget through

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61 Cygni A: Proper Motion

Nuisance Stars

Fringe Contamination

if within 2 arcsec

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SIM Synergy with TPF

TPF inner working Angle

• SIM ~250 closest stars: Identify targets for

TPF-c Definite targets: SIM finds

rocky planets - in the habitable zone

Potential targets: 2- SIM

earths - enrich TPF target lists

Avoid targets: SIM finds a giant planet in the habitable zone

Catch planets when they are 4 /d = 65 mas from star.

TPF Timing:

Inner Working DistanceInner Working Distance

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Epicurus (341-270 B.C.)

“There are infinite worlds both like and unlike this world of ours ... we must believe that in all worlds there are living creatures and plants and other things we see in this world…”

Greek philosopher in Athens where he opened a school of philosophy

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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Gliese 436: Velocity vs. Phase

Msini = 21 MEarth

M ~ 21 MEarth

a = 0.03 AU

K ~ Mpl / a1/2

3 Mearth at1 AU

K = 10 cm/sAt 1 AU,RV can detect20 MEarth

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• What fraction of young stars have gas-giant planets?– Only SIM astrometry can find planets around young stars since active

stellar atmospheres and rapid rotation preclude radial velocity or transit searches

• Do gas-giant planets form at the “water-condensation” line? – SIM will survey ~200 stars to a level adequate to find Jovian or smaller

planets on orbits <1 AU to >5 AU around stars from 25-150 pc– 4 as precision NAngle (50-150 pc) and 12 as precision WAngle (25-

50 pc)• Does the incidence, distribution, and orbital parameters of planets change

with age and protostellar disk mass? – Study of clusters with ages spanning 1-100 Myr to test orbital migration

theories– Correlate with Spitzer results on disks (4-24 m)

• Where, when, and how do terrestrial planets form ?– Understand the formation and orbital migration mechanisms of the

giant planets• No other technique before and possibly including TPF (RV, AO imaging,

IR interferometry) can credibly claim to find planets down to Saturn-Jupiter mass within 1-10 AU of parent stars at 25-150 pc

How Do Planetary Systems Form and Evolve?

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JWST and AO Imaging Will Find Young Jupiters in Large Orbits (>30 AU)

• ESO and other telescopes beginning to identify possible gas giants at 10s-100s of AU

• At 5 m NIRCAM on JWST will be powerful tool for finding distant planets outside of 50 AU (3/D=0.575"=30~100 AU at 50-150 pc)

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Possible Detections for 1 M primary with 500 m/s• 1 M companion, 4 AU: vrad ~ 11 km/s, P ~ 11 yrs (SB2)•50 MJ companion, 1 AU: vrad ~ 2 km/s, P ~ 1.5 yrs (few years)•50 MJ companion, 0.1 AU: vrad ~ 6 km/s, P ~ 15 days (few days)•10 MJ companion, 0.3 AU: vrad ~ 600 m/s, P ~ 50 days (few months)

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Adaptive Optics Results

• AO Observations of Northern targets nearly complete from Palomar (Tanner, Dumas, Hillenbrand, Beichman)– K=9 mag at 1-2″– 14 out of 14 Pleiades targets

• 5 targets have 8 visual companions (>2.5″)

– 16 out of 19 Tau Aur targets • 11 have 20 visual

companions (>2.5″)• 80 hours scheduled for March 2004

to observe 15 stars in Sco Cen and Upper Sco with VLT AO (Dumas et al.)

• Speckle observations of Northern targets planned from Keck (Ghez)– In 2000, identified 3 potential

targets with companions <1″• Keck-Interferometer suggests V830

Tau is multiple

BP Tau

Hii1309 (Pleiades)

3.1"