1 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.

2 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

3 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?

4 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: 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

5 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!

6 Astrometric Planet Detection: What do we derive from SIM measurements? Astrometry can measure all of the orbital parameters of all planets. Orbit parameter Planet Property Mass Atmosphere? Semi-major axis Temperature Eccentricity Variation of temp Orbit Inclination Coplanar planets? Period Sun’s reflex motion (Jupiter) ~500 µas Sun’s motion from the Earth ~0.3 µas 1A.U. ~ 150,000,000 km ~80 A.U.

7 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).

8 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.

9 Where is the most interesting search volume?

10 Search for Terrestrial Planets SIM adds direct information on masses and orbits for fuller characterization of planets from Earths  Jupiters 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 ~ D visits over 5 years. (or D visits or visits…) –50 2D visits => ~3 M earth for 1AU orbit around the 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)

11 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 visits 60 stars Habitable Zone 1 L(sun) 4L(sun) Terrestrial sized planets (18 pc)

12 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 –M Planet = M star *R star /R Planet SIM measures R planet by using Kepler’s 3 rd law, from the period of the planet and the mass of the star.

13 Planet mass sensitivity vs distance Best 240 targets are all within 30 pc

14 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

15 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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17 Planetary Gravitational Lensing

18 An Important Example of Using Astrometry Deduce planets orbiting nearby stars Motion of our sun ( ) 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)

19 One Jupiter mass (1 M J ) 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

20 NEWS Scientists 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 1000 µas 1000 µas How Much Wobble?

22 Astrometric Planet Detection: What do we derive from SIM measurements? 1A.U. ~ 150,000,000 km ~80 A.U. Astrometry can measure all of the orbital parameters of all planets. Orbit parameter Planet Property Mass Atmosphere? Semimajor axis Temperature Eccentricity Variation of temp Orbit Inclination Coplanar planets? Period Sun’s reflex motion (Jupiter) ~500 µas Sun’s motion from the Earth ~0.3 µas

23 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?

24 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.

25 EJS 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

26 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

27 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

28 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 masmid-L2 yr

MLR of VLMs

34 Primary SIM Targets 250 A, F, G, K, M dwarfs within ~15 pc – Doppler 1 m s -1 Jupiters & Saturns within 5 AU – SIM: 30 obs. during 5 yr (1  as) 3 M AU 6 K-giant reference kpc – Located within 1 deg of each target – Doppler vetting for 25 m/s 5 

35 Radial Velocity Planet Searches Detection Limit: ~ 0.2 M 1 AU M earth Gl 436 Gl Cnc d 55 Cnc d  Ara  Ara RV Limitations:  Only a < 0.1 AU  M > 10 M earth ( Butler et al. McArthur et al., Santos et al. )

36 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 Dwarfs

37 Nominal SIM Discovery Space Unique SIM Domain: M EARTH Near Habitable Zones Unambiguous Mass Co-planarity of orbits in multi-planet systems Orbital: a, P, e SIM Domain MASS (M Earth )     1 M 1 AU for d= 1 pc ==> 3 microarcsec...

38 Democritus: Pre-Socratic Greek philosopher ( BC ). Pre-Socratic Greek philosopher 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.”

39 Poor Detect- ability Doppler Survey of 1330 Nearby Sun-like Stars Extrapolation: 6% of stars have giant planets beyond 3 AU Armitage, Livio, Lubow, Pringle et al Trilling, Benz, Lunine 2002 Model: Inward Migration: Planets left behind as disk vanishes Rise?

40 Planet – Metallicity Correlation Fischer & Valenti 2005 Abundance Analysis of all 1000 stars:SpectralSynthesis Valenti & Fischer P planet ~ ( N Fe / N H ) Fe/H Fe/H

41 Models of Protoplanetary Disks of Gas & Dust Theoretical Planet-Formation: Dust Growth  pebbles/rocks Grav. Runaway Gas Accretion Migration & Interactions Formation of Planetary Systems:Observations mm-wave dust emission IR Excess/Spectra & SEDs HST Imaging  M DISK = M JUP Disk Lifetime ~ 3 Myr The Solar System Paradigm

42 Multi-Planet Interactions Levison, Lissauer, Duncan Planet “Embryos” (~M Earth ) Scatter, Collide, Stick, Accrete Gas Chaos After 21.5 Myr After 30 Myr Lone Close-in, Jupiter in Eccentric Orbit.

43 Levison, Lissauer, Duncan 1998 Size  Planet mass (in M earth ) above each planet. Peri - Apo of orbit AU --- Rocky Planets will Outnumber jupiters. Monte Carlo Examples of Planetary Systems

44 Low-Precision Planet Search 400 AFGKM stars at 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  30 pc reveals: 30 M earth at 1 AU

45 Error bars are 1 uas SIM: 3 Earth-Mass Planets d = 5pc precision 1 microarcsec

46 61 Cygni A Exp. Error Photons Angle sep. Planet jitter Failure Prob. 1o1o

47 Typical M Dwarf Companion Eliminate Companions: 25 m/s RV Precision RV Vetting of Reference Stars Planets around K giants get through

48 61 Cygni A: Proper Motion Nuisance Stars Fringe Contamination if within 2 arcsec

49 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 Distance

50 Epicurus ( 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

51 Gliese 436: Velocity vs. Phase Msin i = 21 M Earth M ~ 21 M Earth a = 0.03 AU K ~ M pl / a 1/2 3 Mearth at 1 AU K = 10 cm/s At 1 AU, RV can detect 20 M Earth

52 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 5 AU around stars from pc –4  as precision NAngle ( pc) and 12  as precision WAngle ( pc) Does the incidence, distribution, and orbital parameters of planets change with age and protostellar disk mass? –Study of clusters with ages spanning 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 pc How Do Planetary Systems Form and Evolve?

53 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 pc)

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

55 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"