The James Webb Space Telescope: Solar System Science Dean C. Hines1, Heidi B. Hammel2, Jonathan I. Lunine3, Stefanie N. Milam4, Jason S. Kalirai1, George Sonneborn4 1Space Telescope Science Institute, 2AURA, 3Cornell University, 4NASA/GSFC

Abstract! JWST Instrument Capabilities ! The James Webb Space Telescope (JWST) is poised to revolutionize many areas of astrophysical research including Solar System Science. Scheduled for launch in 2018, JWST is ~100 times more powerful than the Hubble and Spitzer observatories. It has JWST Imaging JWST Spectroscopy greater sensitivity, higher spatial resolution in the infrared, and significantly higher spectral resolution in the mid infrared. Wavelength Resolving Power Imaging and spectroscopy (both long-slit and integral-field) will be available across the entire 0.6 - 28.5 micron wavelength Wavelength Pixel Scale Full-Array* Mode Instrument Field of View Mode Instrument (microns) range. Herein, we discuss the capabilities of the four science instruments with a focus on Solar System Science, including (microns) (arcsec) Field of View (λ/Δλ) NIRISS 1.0 – 2.5 150 2.2′ x 2.2′ NIRCam* 0.6 – 2.3 0.032 2.2 x 2.2′ Slitless instrument modes that enable observations over the huge range of brightness presented by objects within the Solar System. NIRISS 0.6 – 2.5 700 single object NIRCam* 2.4 – 5.0 0.065 2.2 x 2.2′ Spectroscopy Imaging NIRCam 2.4 – 5.0 2000 2.2′ x 2.2′ NIRISS 0.9 – 5.0 0.065 2.2 x 2.2′ The telescope is being built by Northrop Grumman Aerospace Systems for NASA, ESA, and CSA. JWST development is led by Multi-Object 3.4′ x 3.4′ with 250k NIRSpec 0.6 – 5.0 100, 1000, 2700 NASA's Goddard Space Flight Center. The Space Telescope Science Institute (STScI) is the Science and Operations Center MIRI* 5.0 – 28 0.11 1.23 x 1.88′ Spectroscopy 0.2 x 0.5′′ microshutters Aperture Mask (S&OC) for JWST. NIRISS 3.8 – 4.8 0.065 ------slit widths 100, 1000, 2700 0.4′′ x 3.8′′ Interferometry NIRSpec 0.6 – 5.0 Single Slit 0.2′′ x 3.3′′ NIRCam 0.6 – 2.3 0.032 20 x 20′′ Spectroscopy 1.6′′ x 1.6′′ JWST Instruments NIRCam 2.4 – 5.0 0.065 20 x 20′′ MIRI 5.0 – ~14.0 ~100 at 7.5 microns 0.6′′ x 5.5′′ slit MIRI 10.65 0.11 24 x 24′′ NIRSpec 0.6 – 5.0 100, 1000, 2700 3.0′′ x 3.0′′ Coronography MIRI 5.0 – 7.7 3500 3.0′′ x 3.9′′ MIRI 11.4 0.11 24 x 24′′ Integral Field MIRI 7.7 – 11.9 2800 3.5′′ x 4.4′′ Near-Infrared Images & Slitless Spectrograph (NIRISS)! Near-Infrared Images Camers (NIRCam)! MIRI 15.5 0.11 24 x 24′′ Spectroscopy Fine Guidance Sensor (FGS)! MIRI 11.9 – 18.3 2700 5.2′′ x 6.2′′ MIRI 23 0.11 30 x 30′′ MIRI 18.3 – 28.8 2200 6.7′′ x 7.7′′

* NIRCam and MIRI have selectable sub-arrays that enable shorter integration times to accommodate bright objects. In addition, observations with NIRCam can employ both modules to yield a 2.2′ x 4.4′ full array FOV.

Moving Targets & Brightness Limitations

Mission requirements for moving target capability Bright Solar System Objects JWST Can Observe • Capability to observe moving targets with apparent rates up • Mars: NIRSpec, NIRCam (Long Wavelength Channel) to 0.030Bottom arcsec /second Left: The JWST/MIRI Near-Infrared Spectrograph (NIRSpec) ! Mid-Infrared Instrument (MIRI)! • Jupiter: MIRI (MRS <10 µm and FND), NIRCam, NIRSpec (Includesinstrument Mars and will beyond, be cooled but not by all a uniquepossible comets) cryocooler system that provides cooling • Saturn: MIRI (MRS, imaging, FND), NIRCam, NIRSpec • Pointingremotely: stability the of cold 0.050 head arcsec is close (3 σ to) for the rate of 0.003 arcsecMIRI/second detectors, which are located • Uranus: MIRI (spectra and imaging), NIRCam, NIRSpec approximately 20 meters from the • Neptune: MIRI (spectra and imaging), NIRCam, NIRSpec Apparentcryocooler Motion compressor Within and JWST electronics. Field of Regard The cryocoolerMinimum rate hasMaximum been rate developed Time to move by 2 Time to move 2 Spatial Resolution for 2µm Diffraction Limit (0.07”) Object Northrop(mas Grumman/sec) (mas Space/sec) Technologyarcmin at min arcmin at max rate (hrs) rate (hrs) Object Angular Diameter (km) 2 µm Spatial IFU size (km) Mars (NGST) 2.5 under contract28.6 to the13.3 Jet 1.2 Diameter Resolution (km) 3”x3” (arcsec) Ceres Propulsion1.0 Laboratory. 18.4 33.3 1.8 Jupiter 0.07 4.5 476 7.4 Mars 7 6800 68 2900 Saturn 0.04 2.9 833 11.4 Jupiter 37 140,000 265 11,350 Uranus 0.02 1.4 1667 24 Saturn 17 120,000 490 21,180 Neptune 0.004 1.0 8333 34 Uranus 3.5 51,000 1020 43,700 Pluto 0.16 1.0 208 34 Neptune 2.2 50,000 1590 68,180 Haumea 0.35 0.89 95 37 Eris 0.22 0.56 152 59 Pluto @ 35 AU 0.1 2400 1600 72,000 JWST Orbit & Field of Regard

Left: JWST will reside in an halo orbit about Example Solar System Observations Sun-Earth L2, which is a benign and essentially unchanging environment. There • Icy Dwarf Planets & KBOs are no significant gravitational torques, and – Spectroscopy & Thermal imaging thermal influences from the Earth and Moon – NRM interferometry of binaries are greatly reduced. The orbit also avoids Earth and Moon’s shadows. • Asteroids & Comets – Spectroscopy & Thermal imaging • Mars – Spectroscopy – Full disk, seasonal variations Right (top): Range of allowable pitch (85˚-135˚), roll ±5˚. • Giant Planets – IFU & Slit Spectroscopy Right (bottom): Target visibility during a single visibility window in red and the total yearly visibility in blue. Targets – Near- and Mid-IR Imaging within 45 degrees of the ecliptic have two visibility – Isolated cloud decks - Jupiter & Saturn windows per year with a minimum duration of 53 days each – Full disk observations - Uranus & Neptune on the ecliptic. Window durations increase with increasing • Planetary Rings latitude. At an ecliptic latitude of 45 degrees or higher the – IFU & Slit Spectroscopy two visibility windows merge and the total visibility continues to increase up until a latitude of 85 degrees where – Near- and Mid-IR Imaging Some of the spectral features from Icy Dwarf planets that potentially can be it reaches the full year. These areas within five degrees of • Icy Moons – Titan, Triton, Enceladus observed using the Fixed Slit (FS) mode of NIRSpec. Appropriate for Pluto, the ecliptic poles define the continuous viewing zone. – Spectroscopy & Thermal imaging Triton, Eris, & Sedna (Stansberry et al. 2012, private comm).

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