Characterization of Exoplanets and The Search for Life With TPF-I/Darwin C. Beichman, W.C. Danchi, P.R. Lawson, Malcolm Fridlund NAI Meeting at 213th AAS Meeting

Grillmair, Burrows, Charbonneau, et al. Nature, 2008 Characterization Already Underway Time-domain transit photometry and spectroscopy yields composition, temperature balance, vertical structure, global circulation for GIANT planets Spatially resolved spectroscopy needed for Earths (atmosphere is small annulus)

C. Beichman, W. C. Danchi, P.R.Lawson Earth Spectrum Earth’s spectrum shows absorption features from many species, including ozone, nitrous oxide, water vapor, carbon dioxide, and methane Biosignatures are molecules out of equilibrium such as oxygen, ozone, and methane or nitrous oxide. Spectroscopy with R~ is adequate to resolve these features.

Masses, Orbits, Visible & IR Photons to Characterize Planets and Search for Life Beichman et al, Protostars and Planets V

Masses, Orbits, Visible & IR Photons At least 35 nearby F,G,K stars are available for joint observations by SIM, TPF-C, TPF-I/Darwin

C. Beichman, W. C. Danchi, P.R.Lawson Earth signal few photons/sec/m 2 at 10  m at 10 pc Star emits 10 7 more in mid-IR Exozodi  300 brighter than earth for ONE Solar System Zodi AU of star (10s of mas) ~ ~ Detecting Earths Is Difficult

C. Beichman, W. C. Danchi, P.R.Lawson Contributors to Community Report

C. Beichman, W. C. Danchi, P.R.Lawson Community Recommendations Ground Interferometry Limited sensitivity Long baselines Protoplanetary disks Space Interferometry 1.Structurally Connected Exozodi for TPF stars Debris Disks Characterize Warm Planets, Super Earths 2.Formation-flying or tethers (long baselines) Characterize >150 Earths General astrophysics

A Small Structurally Connected Interferometer; The Fourier-Kelvin Stellar Interferometer (FKSI) Mission  Observe Circumstellar Material –Exozodi measurements and companions  Detect >20 Extra-solar Giant Planets –Characterize atmospheres with R=20 spectroscopy –Estimate density of planet, determine if rocky or gaseous –Determine main constituents of atmospheres  Star formation --- disks, young planets  Extragalactic astronomy -- AGN nuclei Key Features of Design: ~0.5 m diameter aperture telescopes Passively cooled (<70K) 12.5 m baseline 3 – 8 (10) um Null depth to R=20 spectroscopy PI: Dr. William C. Danchi, GSFC

W. C. Danchi, P.R.Lawson Salient Features Formation Flying Mid-IR nulling Interferometer Starlight suppression (mid-IR) Heavy launch vehicles L2 baseline orbit 5 year mission life (10 year goal) Potential collaboration with European Space Agency Science Goals Detect Earth-like planets in “habitable zone” of nearby stars via thermal emission Characterize physical properties of detected Earth-like planets (size, orbital parameters, presence of atmosphere) and make low resolution spectral observations looking for evidence of a habitable planet and bio-markers such as O 3, CO 2, CH 4 and H 2 O Detect and characterize the components of nearby planetary systems including disks, terrestrial planets, giant planets and multiple planet systems Perform general astrophysics investigations as capability and time permit Terrestrial Planet Finder (TPF/Darwin) Interferometer

W. C. Danchi, P.R.Lawson Properties of a Flagship Mid-IR Observatory Illustrative Properties of a Flagship Mid-IR Observatory Concept Parameter4-Telescope Chopped X-Array Emma Design CollectorsFour 2-m diameter spherical mirrors, diffraction limited at 2 μm operating at 50 K Array shape6:1 rectangular array Array size400 × 67 m to 120 × 20 m Wavelength range6–20 µm Inner working angle13–43 mas (at 10 mm, scaling with array size) Angular resolution2.4 mas to 8.2 mas (at 10 μm, scaling with array size) Field-of-view1 arcsec at 10 µm Null depth10 -5 at 10 mm (not including stellar size leakage) Spectral resolution Δλ/λ25 (for planets); 100 for general astrophysics Sensitivity0.3 µJy at 12 µm in 14 hours (5s) Target Stars153 (F, G, K, and M main-sequence stars) Detectable Earths130 (2 year mission time, 1 Earth per star) Exozodiacal emissionLess than 10 times our solar system BiomarkersCO 2, O 3, H 2 O, CH 4 Field of regardInstantaneous 45 ° to 85 ° from anti-Sun direction, 99.6% of full sky over one year. OrbitL2 Halo orbit Mission duration5 years baseline with a goal of 10 years Launch vehicleAriane 5 ECA or equivalent

C. Beichman, W. C. Danchi, P.R.Lawson Technology for Mid-IR Nulling Interferometer Has Been Demonstrated  Cryogenic systems (JWST)  Integrated Modeling (JWST, SIM)  Starlight suppression (TPF,SIM, Darwin)  Formation flying (TPF,ESA) 9.3 × null with a 32% bandwidth over 5+ hour

W. C. Danchi, P.R.Lawson Milestone #2: Formation Control TPF-I Milestone #2 experiments for the formation precision performance maneuver were completed 30 September 2007 Goal: Per axis translation control < 5 cm rms Per axis rotation control < 6.7 arcmin rms Demonstrated with arcs having 20 and 40 degree chords. Experiments repeated three times, spaced at least two days apart. Milestone Report published 16 January 2008 Formation Control Testbed Example Milestone Data: Rotation maneuver with 20 degree chord segments x axis 2.66 arcmin rms y axis 2.93 arcmin rms z axis 1.67 arcmin rms x axis 4.77 arcmin rms y axis 5.14 arcmin rms z axis 2.70 arcmin rms x axis 1.39 cm rms y axis 2.41 cm rms Relative path of robots for an arc with 20 degree chords

C. Beichman, W. C. Danchi, P.R.Lawson 14 ExoPTF Detailed Findings – Nulling IR Interferometer “Since direct detection, either by visible-light coronagraph or infrared interferometer, is the only means to assess Earth-like planet habitability, the decision of which one to fly first should be based on cost and technology readiness at a time when one of the two concepts is ready for implementation. The following actions are therefore recommended:” Detailed Recommendations on nulling interferometry The ongoing efforts to characterize the typical level of exozodiacal light around Sun-like stars with ground-based nulling interferometry should be continued. A vigorous technology program, including component development, integrated testbeds, and end-to-end modeling, should be carried out in the areas of formation flying and mid- infrared nulling, with the goal of enabling a nulling interferometry mission around the end of the next decade. The fruitful collaboration with European groups on mission concepts and relevant technologies should be continued.

Findings and Recommendations IR Photometry and spectroscopy is critical technique for characterization of exo-planets and search for life  Support ground-based interferometry (LBTI, Keck-I, CHARA, NPOI, MRO, Antarctic plateau?) for near-term science (EZ, disks & companions), training, technology  Support TPF-I technology (nulling, cryo interferometry components, formation flying, etc)  Study medium (FKSI) and large (TPF-I/Darwin) missions  Pursue international coordination on mission studies  Fund R&A programs to develop theoretical framework for search for habitable planets and life W. C. Danchi, P.R.Lawson

First EPRAT meeting estec EAS Task Force: Plan of Work  August April 2009:EPR-AT prepares a draft roadmap + Preparation of Draft report  Issue of draft to community - late April?  June 2009:Open workshop (at ESTEC) at which EPR-AT presents draft roadmap report to community and solicits feedback  End of summer 2009:Final roadmap report is presented to ESA and to the scientific community.