Solar System Science
with JWST
Dean C. Hines
Space Telescope Science Institute
JWST Imaging Modes
Mode
Imaging
Aperture Mask
Interferometry
Coronography
5/28/2016
Instrument
Wavelength
(microns)
Pixel Scale
(arcsec)
Full-Array*
Field of View
NIRCam*
0.6 – 2.3
0.032
2.2 x 2.2′
NIRCam*
2.4 – 5.0
0.065
2.2 x 2.2′
NIRISS
0.9 – 5.0
0.065
2.2 x 2.2′
MIRI*
5.0 – 28
0.11
1.23 x 1.88′
NIRISS
3.8 – 4.8
0.065
------
NIRCam
0.6 – 2.3
0.032
20 x 20′′
NIRCam
2.4 – 5.0
0.065
20 x 20′′
MIRI
10.65
0.11
24 x 24′′
MIRI
11.4
0.11
24 x 24′′
MIRI
15.5
0.11
24 x 24′′
MIRI
23
0.11
30 x 30′′
STScI
DCH - 2
NIRCam Imaging
5/28/2016
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MIRI Imaging
1.23′
1.88′
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NIRISS: Non-Redundant Mask
5/28/2016
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NIRCam & MIRI Coronagraphs
5/28/2016
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JWST Spectroscopy Modes
Mode
Slitless
Spectroscopy
Multi-Object
Spectroscopy
Single Slit
Spectroscopy
Integral Field
Spectroscopy
5/28/2016
Instrument
Wavelength
(microns)
Resolving Power
(l/Dl)
Field of View
NIRISS
1.0 – 2.5
150
2.2′ x 2.2′
NIRISS
0.6 – 2.5
700
single object
NIRCam
2.4 – 5.0
2000
2.2′ x 2.2′
NIRSpec
0.6 – 5.0
100, 1000, 2700
3.4′ x 3.4′ with 250k
0.2 x 0.5′′ microshutters
slit widths
0.4′′ x 3.8′′
0.2′′ x 3.3′′
1.6′′ x 1.6′′
NIRSpec
0.6 – 5.0
100, 1000, 2700
MIRI
5.0 – ~14.0
~100 at 7.5 microns
0.6′′ x 5.5′′ slit
NIRSpec
0.6 – 5.0
100, 1000, 2700
3.0′′ x 3.0′′
MIRI
5.0 – 7.7
3500
3.0′′ x 3.9′′
MIRI
7.7 – 11.9
2800
3.5′′ x 4.4′′
MIRI
11.9 – 18.3
2700
5.2′′ x 6.2′′
MIRI
18.3 – 28.8
2200
6.7′′ x 7.7′′
STScI
DCH - 7
NIRISS Wide-Field Slitless Spectroscopy
5/28/2016
STScI
DCH - 8
NIRISS Single-Object Slitless Spectroscopy
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STScI
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NIRSpec Apertures
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NIRSpec Micro-Shutter Array
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NIRSpec Micro-Shutter Array
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Example Solar System Observations
• Trans-Neptunian Objects – Icy Dwarf Planets & KBOs
•
•
•
•
– Thermal imaging & Spectroscopy
– NRM interferometry for astrometry of binaries
Asteroids & Comets
– Thermal imaging & Spectroscopy
– NRM interferometry for astrometry of binaries
Mars – Spectroscopy
– Full disk, seasonal variations
Giant Planets
– Isolated cloud decks of Jupiter & Saturn
– Full disk observations of Uranus & Neptune
Icy Moons – Titan, Triton, Enceladus
5/28/2016
STScI
DCH - 13
Bright Solar System Objects
• Mars: NIRSpec, NIRCam (Long Wavelength Channel)
• Jupiter: MIRI (MRS <10 µm and FND), NIRCam, NIRSpec
• Saturn: MIRI (MRS, imaging, FND), NIRCam, NIRSpec
• Uranus: MIRI (spectra and imaging), NIRCam, NIRSpec
• Neptune: MIRI (spectra and imaging), NIRCam, NIRSpec
Angular
Diameter
(arcsec)
Diameter (km)
2 µm Spatial
Resolution (km)
IFU size (km)
3′′x3′′
Mars
7
6800
68
2900
Jupiter
37
140,000
265
11,350
Saturn
17
120,000
490
21,180
Uranus
3.5
51,000
1020
43,700
Neptune
2.2
50,000
1590
68,180
Pluto @ 35 AU
0.1
2400
1600
72,000
Object
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Giant Planet Imaging with NIRCam
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Saturn Rings
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NIRSpec IFU: Uranus
Uranus image from 12 July 2004,
solar elongation 133°
Ecliptic
Image from Keck Observatory
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Slit Observations of Neptune
Neptune image from 27 July 2007,
solar elongation 163°
0.2 x 3.3 arcsec slit
Ecliptic
Image from Keck Observatory
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STScI
DCH - 18
MIRI IFU of Uranus
Uranus image from 12 July 2004,
solar elongation 133°
5-7.8 μm channel
3.7x3.7 arcsec
Ecliptic
Image from Keck Observatory
5/28/2016
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DCH - 19
MIRI IFU Comet Temple 1
5-7.8 μm
channel
3.7x3.7 arcsec
HST Image (Feldman & Weaver)
5/28/2016
STScI
DCH - 20
MSA of Comet Temple 1
NIRSpec microshutter
pseudo
long slit
shutters opened on diagonal
Each open shutter is 0.2x0.46
arcsec
HST Image of Comet
Holmes (2007)
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STScI
DCH - 21
NIR Spectroscopy of Icy Moons
5/28/2016
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Light Curve for Pluto
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Mission Requirements for Moving Targets
• Capability to observe moving targets with apparent rates up to
30mas/second
(Includes Mars and beyond, but not all possible comets)
• Pointing stability of 50 mas (3σ) for rate of 3 mas/second
Minimum rate
(mas/sec)
Maximum rate
(mas/sec)
Time to move 2
arcmin at min
rate (hrs)
Time to move 2
arcmin at max
rate (hrs)
Mars
2.5
28.6
13.3
1.2
Ceres
1.0
18.4
33.3
1.8
Jupiter
0.07
4.5
476
7.4
Saturn
0.04
2.9
833
11.4
Uranus
0.02
1.4
1667
24
Neptune
0.004
1.0
8333
34
Pluto
0.16
1.0
208
34
Haumea
0.35
0.89
95
37
Eris
0.22
0.56
152
59
Object
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•
Schematic for Moving Target Observation
MT offset command repositions Guide Star and initiates moving guide star tracking
– MT ephemeris defines guide star position such that science target is in SI aperture
– ACS iterates offset slew calculation and computes guide star position P3 at time T3
– ACS returns T3 and P3 to ISIM Scripts; ISIM sets up FGS for track mode
– ACS executes offset slew from P2 to P3 prior to T3
TE = End of Ephemeris
– ACS waits until T3 and then starts MT tracking of guide star
Science exposure ends
6
Moving Target GS Track
Commanded Guide Star
position for ID/ACQ
Acquired
GS position
2
1
Science exposure starts
5
4
Executed offset slew from P2 to P3
Remove slew error
3
32x32 track box follows guide star
GS position P3 at time T3
not drawn to scale
5/28/2016
TS = Start of Ephemeris
DCH - 25
Recent Progress on Moving Target Capability
•
•
•
•
•
•
•
•
•
Moving targets with apparent rates up to 30 mas/second
Includes Mars and beyond, but not all possible comets
Pointing stability of 0.050 arcsec (3σ) for rate of 0.003 arcsec/second
Defined the operational concept and the commands/telemetry
exchanged between observing scripts and spacecraft attitude control
for autonomous execution of moving target observations.
Preliminary Design Review for moving target capability will be in
December 2012
Will include first simulations of moving target pointing performance
using non-linear stability analysis with dynamics model for JWST
observatory
Moving target Critical Design Review will be in summer 2013
Moving target observations will be supported in first year of JWST
observing
Cycle 1 Call for Proposals in 2017
5/28/2016
STScI
DCH - 26
Recent Progress on Moving Target Capability
•
•
•
•
•
•
•
•
•
Moving targets with apparent rates up to 30 mas/second
Includes Mars and beyond, but not all possible comets
Pointing stability of 0.050 arcsec (3σ) for rate of 0.003 arcsec/second
Defined the operational concept and the commands/telemetry
exchanged between observing scripts and spacecraft attitude control
for autonomous execution of moving target observations.
Preliminary Design Review for moving target capability will be in
December 2012
Will include first simulations of moving target pointing performance
using non-linear stability analysis with dynamics model for JWST
observatory
Moving target Critical Design Review will be in summer 2013
Moving target observations will be supported in first year of JWST
observing
Cycle 1 Call for Proposals in 2017
5/28/2016
STScI
DCH - 27
SODRM 2012 by Category
Exoplanets
Distant
Galaxies &
Cosmology
Galactic
Nearby
Galaxies
5/28/2016
STScI
DCH - 28
Distribution of Total Exposure Times
per target per instrument
Cumulative Histrogram:
Median exp. = 0.38 hours.
Mean exp. = 1.84 hours.
Solar System
Exoplanets
Galactic
Nearby Galaxies,
Distant Galaxies & Cosmology
Calibration.
5/28/2016
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Solar System Programs
1. Asteroids – NIRSpec & MIRI slit spectroscopy
2. Bright Comets – NIRSpec & MIRI IFU, NIRCam imaging
3. Ice Giants – NIRSpec & MIRI IFU, NIRCam, MIRI Imaging
4. Icy Dwarf Planets – NIRSpec spectroscopy, MIRI 25µm imaging
5. KBOs – NIRSpec slit spectroscopy, NIRCam & MIRI imaging
6. Mars – NIRSpec & MIRI IFU spectroscopy
7. Outer Planet Satellites – NIRSpec & MIRI slit spectroscopy
8. Periodic Comets – NIRSpec & MIRI slit spectroscopy
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JWST & Solar System Science
• JWST is a powerful, general-purpose observatory with the
capabilities to address a wide range of scientific questions:
– From measuring the first light in the universe
– To the detailed study of our Solar System
• JWST Operations is planning for Solar System Science
– Moving target capabilities
– Bright object modes
– SODRM studies for exercising the system and
optimizing efficiency
• The JWST Project encourages strong participation from
the Solar System Science Community
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Fin
5/28/2016
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