A Starshade for JWST: Science Goals and Optimization Rémi Soummer (STScI) November 12th, 2009 and the New Worlds Probe team W.Cash et al. Thursday, November 12, 2009 blue histogram in themeetings lower are background of noted the inat figure. green. the Also top TPF available (left).Figure publications at 1. http://olbin.jpl.nasa.gov/news/tpf are Programmatic shown events in are dark shown blue. in black. The New changing Project ideas and funding technology is is shown highlighted by in the red. Important Bill Clinton George W. Bush Barack Obama The history of TPF from 1999 to 2009 is shown as a timeline. Presidents and NASA Administrators are shown Dan Goldin Sean O’Keefe Mike Gri!n Ed Weiler Al Diaz Mary Cleave Alan Stern Ed Weiler Anne Kinney Rick Howard Jon Morse President War in Afghanistan War in Iraq G. W. Bush announces Hurricane Katrina Sub-prime October 2001 March 2003 August 2005 New Vision for NASA Mortgage Meltdown August 2008 TPF Foundation Science 14 January 2004 Adv. Cryocooler Technology Develop. Program TPF-C Instrument Concept Studies NASA Releases NASA Astrophysics Strategic April 2000 October 2002 May 2005 The Vision for Mission Concept Studies Origins Roadmap 2000 Origins Roadmap 2003 Strategic Roadmap #4 Space Exploration JPL 400-887 JPL 400-1060 The Search for February 2004 TPF/Darwin Planning February 2008 Earth-like Planets Noordwijk Worlds Beyond: NASA Releases NASA announces 19-21 April 2006 Report of the ExoPlanet Columbia Accident TPF-C and TPF-I NRC Panel Review Task Force Prelim. Architecture Final Architecture StarLight Investigation Board as a separate of TPF Science NASA/ESA Letter of ESA Cosmic Vision Decadal Review TPF Book Review Review Cancelled Report Vol. 1 missions Requirements Agreement Expires Proposals Due RFI Responses Due May 1999 12-14 Dec 2000 11-13 Dec 2001 February 2002 August 2003 April 2004 Sept 2004 Dec 2006 June 2007 April 2009 Decadal Review Concept Studies Interferometer or CoronagraphTPF-C and TPF-I Deferred Inde!nitely Decadal Review 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Darwin and Astronomy Darwin/TPF Meeting Darwin/TPF TPF/Darwin Meeting IAU Colloq. 200 Spirit of Lyot March 2009 Stockholm, Sweden Heidelberg, Germany Saas-Fee San Diego, USA Villefrance-sur-mer, France Berkeley, USA Exoplanet 17-19 Nov 1999 June 2002 22-25 April 2003 9-12 Feb 2004 26-29 July 2004 3-7 Oct 2005 June 2007 Community Report January 2001 Biosignatures and JPL Pub 09-3 A New Pupil for Planetary Properties April 2003 Coronagraph SPIE Exoplanets II SPIE Exoplanets III Extrasolar Planets to be Investigated Phase-Induced Workshop San Diego, USA San Diego, USA August 2005 August 2007 Feb 2009 D. Spergel by the TPF Mission Leiden Amplitude 2-6 Feb 2004 June 2006 TPF-I Milestone #3 astro-ph/0101142 JPL Pub 01-08 Apodization Oct 2004 Terrestrial Planet March 2007 Broadband Nulling March 2005 O. Guyon Precursor Science Finder Coronagraph Terrestrial Planet Demonstration Technology Plan February 2001 Summary Report on for the Terrestrial Science and Technology Finder Interferometer TPF Science for the Terrestrial Apodized Square Aperture Architecture Studies April 2003 Planet Finder De"nition Team Science Working Tech & Design Planet Finder P. Nisenson & C. Papaliolios for the Terrestrial Adaptive Nulling JPL Pub 04-14 (STDT) Report Group Report Jan 2008 Expo Coronagraph ApJ 548, L201 (2001) Planet Finder O. Lay, JPL Doc 34923 JPL Pub 07-1 TPF-I Milestone #2 Pasadena JPL Pub 05-08 JPL Pub 02-11 M. Jeganathan, 14-16 Oct 2003 Formation Control & R. Peters Demonstration April 2001 January 2005 June 2005 July 2007 Sept 2006 Symmetric Nulling General Astrophysics Technology Plan TPF-I Milestone #1 May 2002 March 2003 Coronagraph Beam Combiners Technology Plan and Comparative for the Terrestrial Adaptive Nuller Band-limited masks Workshop E. Serabyn & M. M. Colavita for the Terrestrial Planetology with the Planet Finder Demonstration M. Kuchner & W. Traub JPL Pub 05-01 Appl. Opt. 40, 1668 (2001) Planet Finder Terrestrial Planet Finder Interferometer ApJ 570, 900 (2002) Mission JPL Pub 05-05 August 2008 JPL Pub 03-07 June 2006 October 2006 JPL Pub 05-01 Earth-Like TPF-C Milestone #2 TPF-C Milestone #1 Kepler August 2003 Exoplanets: 9 x 10!"# contrast Monochromatic contrast Launch SPIE Exoplanets I The Science of NASA’s 10% bandwidth Demonstration March 2009 San Diego, USA Navigator Program July 2006 JPL Pub 06-5 Petal-shaped Occulter Spitzer W. Cash Corot SPIE Meeting SPIE Meeting Launch SPIE Meeting SPIE Meeting Launch Munich, Germany Waikoloa, USA August 2003 Glasgow, UK SPIE Meeting Marseille, France March 2000 August 2002 June 2004 Orlando, Florida Dec 2006 June 2008 timeline.pdf. May 2006 !""#$%&'()*&$"+*,-&-.-/"('"0/!1*(%(23""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""4(5/)*6/*-"78(*,(),1&8"9!:*(;%/<2/<="""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""">/-/)"?="@$;,(*"""""""""""""AB"C.%3"DBBE Thursday, November 12, 2009 Context • Terrestrial Planet Finder • NASA is interested in new strategies consistent with current budget ‣ Mission concept studies ‣ Exoplanet Community Report ‣ Possibility of a “medium-class” mission (~$700M) • Discovery proposal 3 years ago (Cash et al.) • Medium mission ‣ “small coronagraph” e.g. PECO 1.4 m ‣ occulter possible if host telescope available ‣ small interferometer e.g. FKSI 3 Thursday, November 12, 2009 New Worlds Probe (NWP) Concept ~50,000-70,000km 50-70 m diameter ‣ Science capabilities given JWST instruments (what can we detect? biomarkers?) ‣ Observing time, available stars, Field of Regard, DRM ‣ Operations (alignment, planning & scheduling, target acquisition, overheads) ‣ Starshade itself 4 Thursday, November 12, 2009 External Occulters: early ideas • Lyman Spitzer, in American Scientist 1962 - “This method involves the use of a large occulting disk far in front of the telescope to reduce the light from the star.” - “In the same way that the diffracted light from a telescope mirror can be reduced by a smooth reduction of the reflectivity towards zero at the edge, the shadow behind an occulting disk can be made much blacker if the transparency of the disk varies smoothly at the edge of the disk rather than abruptly; a reduction of intensity within the shadow by an order of magnitude was achieved with the use of an occulting disk edged with sharp spikes”. 5 Thursday, November 12, 2009 External Occulters: early ideas • Gordon Woodcock 1974 6 Thursday, November 12, 2009 External Occulters: early ideas 7 Thursday, November 12, 2009 External Occulters Plain Apodized Starshaped occulter occulter Shadow is not optimum, Much better Star shaped occulter (approximation spot of Arago-Poisson shadow of the continuous apodization) Umbras Boss 2000~2002 Web Cash: analytical functions, e.g. ‘hypergaussian’ Bob Vanderbei: optimal numerical solutions 8 Thursday, November 12, 2009 Parameters for the Starshade • Define a geometric inner working angle (IWA) 500 1000 1000 1000 500 500 star ‣ IWA ~ D/z 500 1000 planet ‣ Shadow properties (Fresnel propagation) ~ D2/λz • there is a minimum distance & size for a given set of IWA, contrast, bandwidth and other constraints. • occulter diameter (and distance) increase with ‣ decreasing IWA ‣ telescope diameter ‣ bandwidth (easier on the blue side than red side) ‣ contrast 9 Thursday, November 12, 2009 James Webb Space Telescope • Observatory ‣ 6.5 m, segmented ‣ modest optical quality (diffraction limited at 2 microns, SR=80%) ‣ Imaging and spectroscopy from 0.6 to 25 microns • Near Infrared Camera (NIRCam) ‣ 2 instruments: short arm (0.6-2.3 μm) and long arm (2.4-5.0 μm) ‣ several filters, broadband and medium band • Near Infrared Spectrograph (NIRSpec) ‣ 0.6-5.0 μm, R=40-100 (prism) and R=1000 • Mid Infrared Imager (MIRI) • Tunable Filter Imager (TFI) 10 Thursday, November 12, 2009 NWP: Science Goals Summary • Can we design an occulter to image and characterize and Earth-like planet? ‣ contrast goal 1e-10 ‣ characterize habitability & possible biomarkers, near infrared: O2, H2O, CO2, CH4 ‣ possibility of thermal emission as well? (radius and temperature) • Characterization of giant planets is interesting in the near infrared • Imaging & Spectroscopy from 0.6 to 1.7 μm covers large science program Turnbull et al. Marley et al. 11 Thursday, November 12, 2009 NWP: Science Goals Summary • 1) Find and characterize planetary systems including terrestrial planets in the habitable zone ‣ 20 - 30 nearby extrasolar systems can be observed and mapped ‣ If ηearth is >0.5, there is a high probability of observing ~5 terrestrial planets ‣ With ~3 revisits each, we can characterize their atmospheres, and establish the terrestrial planet’s habitable zone residency. Rotation? Biomarkers? Oxygen? • 2) Characterize known RV planets (Jupiters, Neptune, super Earths) ‣ Mass: disentangle m sin(i) with inclination measurement ‣ Atmospheric composition, gravity, temperature & radius if emitted light can be measured • 3) Determine brightness and structures of exozodiacal disks. NWP Can Perform a Variety of Exoplanet Science 12 Thursday, November 12, 2009 Table 1. Known radial velocity planets for which the angular separation is larger than 60mas (here the angular separation is calculated using the semi-major axis). The contrast is calculated for a separation corresponding to the semi-major Large-separationaxis, and assuming quadrature. There areRV 18 planets planets for which the separation is larger than 120mas, respectively