National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan SIM-Lite Update M. Shao JPL © 2008 California Institute of Technology. Government sponsorship acknowledged.

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan Outline SIM-Lite Instrument Update -6m baseline, 50cm, ~900M cost Technology Update -Systematic errors and floor SIM-Lite terrestrial planet discovery capability Double blind multiple planet study summary The changing landscape of exoplanet science and the role of SIM-Lite

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan SIM and SIM-Lite SIM PlanetQuest SIM- Lite Note: Centaur upper stage used in both vehicles. -Inside fairing. -ETSO orbit ParameterSIM-PQSIM-LITE Wide Angle (global) accuracy2.4 uas3.6 uas Narrow Angle Accuracy0.7 uas1.0 uas Mag limit20 mag # Stars surveyed 1Mearth-HZ~130~60 Mass (with reserve)6800 KG4300 KG Number of Interferometers32 Science Baseline9m6m Guide-1 Baseline7.2m4.2m Guide-27.2m0.3mTscope Launch Vehicle Atlas V Payload Risk ClassAB BCD schedule77 mon58 mon BCD cost to go1470 M940 M Mission Ops 5yrs400M170 M Smaller size also meant end to end performance test of flight hardware could be done in thermo-vac chamber at JPL, instead of S/C contractor.

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan From Technology to Flight Component Engineering Much of the SIM hardware for flight already exists in engineering model and brassboard form. Spacecraft & Instrument Electronics Instrument External Metrology Launcher Internal Metrology Launcher Metrology Source Double Corner Cube Siderostat ball screw Astrometric Beam Combiner (Drawings released) Fast Steering Mirror

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan Instrumental Systematic Errors Thermal drift affects all measurements For narrow angle observations, we chop between target and reference stars every 90 sec. When this observation procedure was tested in the MAM testbed we showed that thermal drift noise became white after chopping. The remaining question, is the thermal drift in the MAM testbed, representative of the thermal stability we will see on SIM in orbit? -Detailed (>10 4 node) thermal model of SIM shows current design ~5 times more stable on orbit than testbed is in Lab. 1pm/6m = ~0.04uas

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan Ultra Deep Search for Earth Clones HIP 1475 HIP HIP GAIA (70 µas) 1 m/s TPF-C (8 m) M2K2G2F2 Planets ~Tidally Locked Concentrate a lot of observing time 40% on a small number ~60 for SIM-Lite) over a 5 year mission. To achieve sensitivity to 1 (1 AU) scaled to the luminosity of the star

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan Double Blind Test, Astrometric Detection of Earths in Multiplanet Systems 48 Planetary systems 95 planets & ~300 Asteroids 48 detectable planets ( 5.8) Threshold 1M 1AU Two key metrics Confidence of detection Completeness

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan The Current Era of Exoplanet Science (Where does SIM-Lite fit in?) Where are we now? ->350+ exoplanets have been found, Mostly RV (4.5 Mearth, in few day orbits) -Kepler is in norbit, coupled with JWST, get spectra of Jovians (100s) -All sky transit missions have been proposed -Technology for an astrometric mission is complete -Considerable technology progress for direct imaging from space. -Extreme AO coronagraphs on 8~10m telescopes to come on-line in 2010/2011. Spectra of self luminous jupiters soon. Perhaps spectra of planets in reflected light with TMT, ELT Jupiters Neptunes Hot Sup-Earth Terrestrial In HZ Discover (Mass) (Orbit) Spectra Self luminous Jupiters Simplified Diagram Where we are. Where are we going.

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan Where is the next frontier, where does SIM-lit fit? The next Major (Space) advance in exoplanet research is the discovery of Terrestrial planets in the habitable zone. -SIM plays a pivotal and unique role After discovery, spectroscopic characterization Earth-clones with large space coronagraphs/interferometers to look for biosignatures.

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan Discovering Earths, Why SIM is Unique The most important parameter, of a planet is its mass. We know a planet is a terrestrial planet IF and ONLY IF we know its mass. -We cant tell the mass of a planet from its color, and brightness. Neptune is 4X the diameter of Earth. A 4 AU has the same apparent magnitude as 1 AU. The apparent brightness of a planet depends on the orbital phase angle. Pale blue dot, Neptune an ice giant To Observatory

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan Discovering Earths, (False Alarms) With a single image (and spectra) -Weve imaged the first Earthlike planet in the habitable zone, but this planet doesnt have Oxygen and it has a lot of Methane OR with Astrometry -Weve measured the spectra of a 15 Mearth ice giant planet at 4AU, it has a lot of methane in its atmosphere and no oxygen. The discovery of a habitable planet around a nearby star will be a major scientific discovery. -If the probability of a false alarm is in the 10s of percent, this does NOT constitute a major discovery -The claim of finding a planet in the habitable zone can be made with a Measured orbit, (Not a guess) -The claim of finding a terrestrial planet can be made with a Measured mass, not a guess of the mass. Pale blue dot, Neptune an ice giant To Observatory

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan Three Planets Imaged Around HR 8799 masses of 5-13 M JUP Ages, Models, Masses uncertain – Assumed Age: 60 Myr 5-13 M JUP – Age Range: 30 Myr-1.2 Gyr 40 M JUP – Are these Planets or Brown Dwarfs? Orbits unstable? SIM determines masses directly SIM will calibrate mass, luminosity, age relationships which make imaging studies so uncertain Imaging: Planet Status Uncertain Without Masses and Ages 12 SIM Lite Science Review

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan SIM Will Help Establish How Planetary Systems Form & Evolve Astrometry can find gas giants within 1-5 AU of parent stars –Mass measurements critical to evolutionary models –What fraction of young stars have gas-giant planets? –Do gas-giant planets form at the water-condensation line? AO imaging will find distant planets (>10 AU), but cannot determine mass, find inner planets Variability, spectral jitter, & rotation >>100 m/s preclude planet detection via RV, transit Log Age (Myr) D=140 pc 25<D<50 pc Disk Lifetime << 100 Myr 13 SIM Lite Science Review

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan SIM Probes the Broad Planet Mass Range Around Young Stars SIM surveys critical mass and age range – Gas giants around youngest stars (1-10 Myr at 140 pc) – Gas and icy giants around closest stars (>10 Myr at <50 pc) – Large rocky planets around nearby, young, low mass stars GAIA can find only Jupiters around the closest young stars (d 10 Myr) Star spots (<2 as for V=0.05 mag variability at 140 pc) will not prevent detection of gas giants 14 SIM Lite Science Review

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan Astrometry and RV Detection of ExoEarths Given Perfect instruments, the ultimate limitation to both RV and Astrometric detection of exoplanets is astrophysical noise from the target star. -Star spots on the Sun produce 10~12X higher bias to RV than Astrometry (for planets in a ~1 yr orbit). A area spot on the sun produces -~1m/s RV bias (Earth-Sun 0.09m/s signature) -~0.25 uas Astrometric bias (0.3uas signature) Whatever the astrophysical limitations ultimate turn out to be there is a ~12x advantage for astrometry (for 1 yr orbits). -Planets with shorter periods favor RV, planets with longer periods favor astrometry. Spot noise is correlated on time scale of ~1week. Two measurements < 1 week apart will see the same bias due to spots. (Accu;racy improves as sqrt(#weeks) 1 m/s to 0.015m/s takes ~4000 weeks ~80 yrs

National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology M. Shao Jan Summary SIM-lite is much reduce cost version of SIM that still retains the potential to detect Earth Clones around ~ 60 of the nearest stars. (1.3~1.5B) -Its possible that we would get better science searching 160 stars for 2 Mearth planets, but the capability exists to get to 1 1AU. -Find addresses for the nearest potentially habitable planets -SIM-Lite also has a strong astrophysics program, (Dark Matter, stellar physics, compact objects) The technology for SIM is ready. Flight designs and models exist for many flight picometer level precise components.