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Solar System Science with JWST
2012/2013 Workshop Updates

Stefanie Milam JWST Townhall: DPS 2013


44th annual meeting of the Division for Planetary Sciences of the American Astronomical Society · Provide, via the JWST Project members:
­ current instrument specifications and observing modes 14-19 moving tr gets, ­ observatory capabilities (brightness limits,Octobear2012 tracking, http://wthertsci.edu/jwst/science/solar- d Sierra Resort and o ww.s s) Gran sy y case ­ preliminarstem studies from JWST SO-DRM , NV Reno

Goal: fully engage Solar System community and provide tools they need to begin planning their observations with JWST JWST Workshop: Sunday, 14 October 2012 9:00 am - 12:00 noon in the Crystal 3 Room


DPS 2012 Panel and Discussion
· Moving targets--tracking rates, specifically or workarounds · Subarray observations in general and implementing subarrays for NIRISS · NIRSpec Microshutter · Moons near giant planets--how close can you go...also rings (see stray light) · Peak-ups on objects of varying brightness · Possibility of interaction on guide stars between observer and ground system · Shadow observations--very useful for moving targets · Slew time penalty and short-exposure-time science · Stray light issues (crucial for rings and fainter objects as well) · 24 hour scheduling visit--too large for solar system. Are we penalized? · Solar system proposal issues; sociology, panels, overall time · Launch is 6 years away, but now is the time to develop realistic, detailed use cases-----beyond SO-DRM. ·Revised or new solar system white paper(s) ·2008 DPS workshop in Ithaca generated the first of these. ·updated JWST capabilities (NIRISS, moving target, subarrays)


44th Lunar and Planetary Science Conference
March 18-22, 2013 The Woodlands, Texas

· Peripheral Meeting Request · Sunday, March 17 (afternoon) · Same format as DPS · Targeted Invite List


LPSC 2013 Panel and Discussion
· Observational constraints on main asteroids (Vesta, Ceres, etc) · Calibrating across instruments for Solar System bodies (e.g. comets/asteroids)? And will this be part of the observatory calibration, or the observing program? Matching orders? · Post-processing for Moving Targets? · Can we conduct high spatial resolution observations of the Jovian aurora? · How quickly can the microshutter array (MSA) be reconfigured? · Can a long MSA slit be scanned across Saturn to measure time variable phenomena? · Will the observer know where the stuck shutters are? · What are the data volume limits? · Is stray light being considered for bright objects centered vs. on the edge of field? Is there stray light within the instruments?


Few Highlights since DPS 2012
· Moving target tracking rates:
­ JWST's moving target tracking of 30 mas/sec has been successfully implemented. Higher rates of motion may be feasible, though accuracy is not guaranteed.

· Moons, rings near giant planets:
­ A white paper on Rings in the Solar System has been written to consider this science with JWST. This effort is being lead by Matthew S. Tiscareno at Cornell.

· Constraints on Guide Star Availability:
­ Special cases are being considered for key Solar System bodies that may have limited guide star availability throughout the mission lifetime. Timing constraints and specific science needs are being evaluated.

· Brightness on Instruments:
­ As the instruments are delivered and characterized, these constraints are being considered for bright, extended objects.


Focus Groups
· The Solar System working group for JWST is organizing key science focus groups to work with the project and to ensure all needs for "groundbreaking " science are being considered.
­ ­ ­ ­ ­ ­ Small bodies Ice Giants Mars Titan Satellites Others?

· If interested please contact us.


Solar System White Paper
· A new white paper is being prepared as a deliverable to the community from these Workshops.
­ New Science Cases ­ Updates on Brightness, Moving Targets, Instrument Modes, etc.

· Draft ready for comments from the community.
­ Contact: Stefanie Milam, Heidi Hammel, or John Stansberry for more details.


Contact and More Info:
· All presentations, fliers, details:
­ http://www.stsci.edu/jwst/science/solar-system ­ www.jwst.nasa.gov

· Contacts for White Paper:
­ Stefanie Milam: stefanie.n.milam@nasa.gov ­ Heidi Hammel: hbhammel@aura-astronomy.org ­ John Stansberry: jstans@stsci.edu


The Details


LPSC General Remarks
· It is important to establish why the combined spectral and spatial capabilities of JWST are important for accomplishing key bright-object and/or Solar System observations:
­ (1) Essential transitions that are in telluric-opaque intervals: acetylene in particular (12.8 micron) is unobservable from Earth but is one of the brightest hydrocarbon features in giant planet atmospheres, particularly aurora, providing a means to evaluate energetic processes in hydrocarbon-rich atmospheres. This also is a good candidate for exoplanet detection/characterization for the same reason. We need to understand the giant planets in the Solar System in order to place observations of exoplanets in context. ­ (2) Collecting area is only one attribute of a large primary mirror. Diffraction-limited imaging will bring spatial resolution to a level at which essential discoveries are accessible in planetary aurora (particularly the distinct horizontal morphologies of molecular emissions that probe different depths) -- the nature of the interaction between the large Galilean satellites and Jupiter 's polar ionosphere through magnetospheric plasma processes is essential to understanding magnetospheric plasma in the Jovian system. Resolving the spatial distribution of heating across the Galilean satellites also is of interest.


Follow-Up (As of 9/30/13)
­ Moving target tracking rates:
· The JWST program has recognized that the moving target (MT) capabilities are essential. The MT capability for the control system was reviewed late last year and passed with no issues. JWST's moving target tracking of 30 mas/sec has been successfully implemented. Higher rates of motion may be feasible, though accuracy is not guaranteed.

­ Subarray observations:
· We have already demonstrated subarray options for NIRCam to help with brightness limits for the major bright objects in the solar system. We are looking into others and considering cases with the Microshutter Array configurations for NIRSpec.

· Subarray readout with NIRISS is still in a very preliminary stage, though STScI is working with the instrument team and considering observations for bright objects.

­ Moons, rings near giant planets:
· A white paper on Rings in the Solar System has been written to consider this science with JWST. This effort is being lead by Matthew S. Tiscareno at Cornell. · Some of the moons near bright planets have already been considered (e.g. Titan) and others will be investigated in the near future.


Follow-Up: 2
­ Peak-ups on extended objects of varying brightness.
· This will be addressed at a later date.

­ Possibility of guide stars selection by observer.
· There is no expectation that observers will be able to select guide stars.

­ Shadow observations--very useful for moving targets
· These are currently being considered by the operations team at STScI and NASA.

­

Observing and slewing overheads and short-exposure-time science
· We are developing estimates of overheads for all types of observations. · The project is considering many science cases as these policies are developed. These will not be ready until closer to the Cycle 1 Call for Proposals.

­ Stray light issues (crucial for rings and fainter objects as well).
· This issue is important and requires detailed stray light modeling with updated PSFs and the optical-structural model of the observatory. The JWST project will oversee this analysis to ensure it is computed properly.


Follow-Up: 3
­ Have a user calibrator database.
· This will be addressed at a later date.

­ 24 hour scheduling visit too long for time-constrained observations?
· Time-critical observations are supported and will be scheduled to meet the duration of the elongation window specified by the observer ­ which may be less than 24 hours.

­ Solar system proposal issues; sociology, panels, overall time:
· We are holding regular workshops and events for the Solar System community so you will be more engaged in designing JWST observations and will prepare competitive proposals starting a year before launch.

­ Observational constraints on main asteroids (Vesta, Ceres, etc)
· Data for these bodies are being collected to be included along with the Jovian satellites in bright object reports.

­ Calibrating across instruments for Solar System bodies (e.g. comets/asteroids)? And will this be part of the observatory calibration, or the observing program? Matching orders?
· Cross-Instrument calibration is generally handled as part of normal observatory calibration. Some unique calibration needs, e.g. PSFs for coronography, sometimes need to be included as part of the scientific observing program. Guidelines for this will be developed for the Cycle 1 proposal instructions.


Follow-Up: 4
­ Post-processing for Moving Targets?
· This issues is being addressed by the JWST science pipeline processing group. We will communicate progress on this at a future meeting.

­ Can we conduct high spatial resolution observations of the Jovian aurora? Methane, ethylene, acetylene are most important ~10um.
· MIRI brightness limits are currently being updated and this science case will be considered.

­ How quickly can the microshutter array (MSA) be reconfigured?
· The array can be reconfigured in ~1 minute provided that no other instrument configuration or pointing changes are made.

­ Can a long MSA slit be scanned across Saturn to measure time variable phenomena? · We are looking into this and other possible observing techniques for bright objects.


Follow-Up: 5
­ Will the observer know where the stuck shutters are?
· Yes. Shutters that are stuck in the open or closed position will be identified and made available to the observer in the proposal planning tool's visualization.

­ What are the data volume limits?
· The relevant data volume requirement is 458 Giga bits of science data per day.

­ Is stray light being considered for bright objects centered vs. on the edge of field? Is there stray light within the instruments?
· Stray light is being considered for bright objects in and out the main FOV. · By design, stray light is minimized within the instruments. In flight tests will be conducted to evaluate the impact of stray light.