Exoplanet Exploration Exoplanet Exploration! Musings on Space-Based Strategies for the Near-Term Dr. Jennifer J. Wiseman NGC 1300 Carbon planet, artist’s conception, courtesy M. Kuchner (GSFC)

Space-based study of exoplanets will involve current facilities, future facilities, relevant technology development, coordination with ground-based capabilities, and thorough supportive theory and modeling investigations.

Dearth of expended funding for major TPF mission has fueled major creative ideas for approaching exoplanet observations Transits (coordinate with ground-based Radial Velocity measurements) Starlight suppression for direct imaging / spectroscopy Internal Coronagraphy: Multiple concepts External Occulters Interferometry Astrometry Microlensing Debris disk modeling and observations (More…)

Strategies Massive exoplanet community input AAAC Exoplanet Task Force NASA Astrophysics Mission Concept Studies Exoplanet Community Report National Academy Decadal Survey Inputs NASA Exoplanet Assessment Group (ExoPAG)

Community reports AAAC Exoplanet Task Force (Recommendations for vigorous ground-based RV detections, M-dwarf transit studies, a space-based astrometric survey mission, determination of exozodiacal dust obscuration levels, and, if conditions favorable, a flagship imaging and spectroscopic characterization mission.) http://www.nsf.gov/mps/ast/aaac/exoplanet_task_force/reports/exoptf_final_report.pdf Exoplanet Community Report Summary Statement: “The Exoplanet community’s top priority is that a line of probe-class missions for exoplanets be established, leading to a flagship mission at the earliest opportunity.” http://exep.jpl.nasa.gov/exep_exfCommunityReport.cfm

Community reports Whitepapers submitted to Decadal Survey (Multiple techniques, science strategies, technology needs) NASA Astrophysics Mission Concept Studies (studies of mid-class and flagship class future mission concepts, including exoplanet missions)

Nearest term: use current facilities HST / Spitzer (e.g. transit spectroscopy) Herschel (circumstellar material; coordinate with ALMA) Kepler (statistics on planetary systems; need improving ability for ground-based RV confirmation of earth-sized planets) JWST (gas giants and super-Earths?) More…

Next Decade: Depends on Funding (as usual!) Explorer Class missions? ($200 M) (e.g. TESS; may be other follow-on explorer class science?) Discovery Class ($300-400M) (e.g. Kepler -- but will there be future exoplanet Discovery missions? Probe Class ($600-800 M) (will this new mission class get started?) Probe ++ to small Flagship (Astrometric survey) (will probe-class include ~$1 B class missions?) Technology Development

Following decade(s) Flagship Mission concepts (will allow spectral characterization) 4, 8, or 16 meter optical telescope with external occulter and/or internal coronagraph; IR interferometer

Exoplanets & Stellar Astrophysics Technology HST Instruments (STIS, WFC3) Interferometry and coronagraphy theory and testbeds Next Generation UV Detectors

Christopher Stark’s Predictions for TPF July 6, 2006 1,000 particles Uranus-mass object 0 < I < 5 degrees 0 < e < 0.1 30 micron particles? NWO

NASA'S HUBBLE CHASES UNRULY PLANET - The most detailed visible light image from HST offers the strongest evidence yet that an unruly & unseen planet may be gravitationally tugging on a dusty ring around nearby star Fomalhaut (HD 216956). The image of a narrow, dusty ring unequivocally shows the center is 1.4 billion miles away from the star; a distance nearly halfway across our solar system. The most plausible explanation is an unseen planet, moving in an elliptical orbit, is reshaping the ring with its gravitational pull. The geometrically striking ring, tilted toward Earth, would not have such a great offset if it were only being influenced by Fomalhaut's gravity. An offset of the ring center from the star has been inferred from previous lower resolution submm wavelength telescope observations; & by applying theoretical modeling & physical assumptions. HSTs sharp images directly reveal the ring’s offset from Fomalhaut, providing strong evidence at least one unseen planetary mass object is orbiting the star. If the orbiting object were larger than a planet, such as a brown dwarf star, Hubble would have detected it. "Our new images confirm those earlier hypotheses that proposed a planet was perturbing the ring," said astronomer Paul Kalas of UC Berkeley. The ring is similar to our solar system's Kuiper Belt, a vast reservoir of icy material left over from the formation of our solar system planets." The ring's inner edge is sharper than its outer, a telltale sign that an object is gravitationally sweeping out material. Another classic signature of a planet's influence is the ring's relatively narrow width, ~2.3 B miles. Without an object to gravitationally keep the ring material intact, the particles would spread out much wider. The suspected planet may be orbiting far away from Fomalhaut, inside the dust ring's inner edge, between 4.7-6.5 B miles from the star. The ring is ~12 B miles from Fomalhaut, much farther than our outermost planet Pluto is from the sun. These observations do not directly detect the planet, so astronomers cannot measure its mass. They will use computer simulations of the ring's dynamics to estimate its mass. Fomalhaut, a 200-million-year-old star, is a mere infant compared to our own 4.5-billion-year-old sun. It is 25 light-years from the sun in the constellation Piscis Austrinus (the Southern Fish). The Fomalhaut ring is 10-times as old as debris disks previously seen around the stars AU Microscopii and Beta Pictoris, where planets may still be forming. If our solar system is any example, planets should have formed around Fomalhaut within tens of millions of years after the birth of the star. "The size of Fomalhaut's dust ring suggests not all planetary systems form and evolve in the same way -- planetary architectures can be quite different from star to star," Kalas said. "While Fomalhaut's ring is analogous to the Kuiper Belt, its diameter is four times greater." Kalas and his collaborators used HST over a 5-month period in 2004 to map the ring's structure. They used the ACS coronagraph to block out light from the bright star, so they could see details in the faint ring. One side of the faint ring has yet to be imaged, because it extended beyond the ACS field of view. Astronomers plan to map the entire ring later this summer. Kalas & collaborators, James Graham of UC Berkeley & Mark Clampin of GSFC, findings appeared in the journal Nature.

Fomalhaut: Imaging An Exoplanet!! (P. Kalas et al 2009) http://www.nasa.gov/mission_pages/hubble/science/fomalhaut.html

Countdown to Hubble SM4 ! Dr. Malcolm B. Niedner Most HST slides graciously contributed by: Dr. Malcolm B. Niedner HST Deputy Senior Proj. Scientist 16

WFC3 + ACS + NICMOS = Most powerful imaging ever MISSION GOAL: When the astronauts leave Hubble for the last time, it will be at the peak of its capabilities - better than it has ever been before. WFC3 + ACS + NICMOS = Most powerful imaging ever COS + STIS = Full set of tools for astrophysics The mysteries of dark matter and dark energy The architecture of the universe The life story of galaxies The birth and death of stars Recipes for building planets

Pertinent questions What can we do from the ground now, and in the future? What is the significance of circumstellar debris disks? Inter-relationship with planets Indicator of planets Obscuration of planets Predictive of bombardment and subsequent habitability of environment?