JWST Moving Target Observations
JWST can track and observe planets, satellites, and nearly all comets and asteroids more than 1 AU from the Sun.
JWST offers the capabilities necessary for observing Solar System (moving) targets, with high sensitivity and spatial resolution, through imaging as well as low and medium resolution spectroscopy, from 0.6 to 28.5 μm. The observatory is in a solar orbit near Earth's L2 point, so scheduling is more flexible and efficient compared to HST (which is in a low Earth orbit). JWST's thermal design only allows Solar System targets to be observed near quadrature; observations at opposition are not feasible.
Solar System observations with JWST
An overview of JWST's Solar System capabilities, as well as exploration of some possible science applications can be found in Milam et al. (2016) and Norwood et al. (2016). The following list includes links to flyers on some potential science investigations:
General: Overview of JWST's capabilities for observations of Solar System targets
- Solar System GTO & ERS programs: Details of all Guaranteed Time Observations (GTO) and Early Release Science (ERS) programs targeting Solar System objects
Asteroids & near-Earth objects (NEOs): Surface composition, thermal properties
- Giant planets: Vertical and horizontal cloud structures, global circulation, chemistry and composition, thermodynamics
- Giant planet satellites: Volcanic activity on Io, satellite atmospheres, plume activity on Europa and Enceladus, irregular satellites
- Trans-Neptunian Objects (TNOs): Surface composition, diameter/albedo, colors, binarity
Mars: Atmospheric composition, evolution of dust storms and clouds
- Occultations: Minor bodies, rings, mutual events, serendipitous occultations
Rings and small satellites: Discovery and characterization, transient phenomena (ring arcs and spokes), composition
Titan: Atmospheric composition, clouds and hazes, surface temperature, surface changes
- Comets: Dust, gas, nuclei, observability
More detailed examinations of 10 science areas, and a summary of JWST capabilities and operations for moving targets, can be found in a January 2016 special issue of PASP.
Example APT files and ETC workbooks
GTO & ERS
Words in bold are GUI menus/
panels or data software packages;
bold italics are buttons in GUI
tools or package parameters.
APT files can also be downloaded from APT using the tool's main menu: File → Retrieve from STScI → Retrieve using Proposal ID, then enter the proposal ID in the pop-up box, and click OK.
JWST demonstration proposals
An example APT file for observations of Solar System objects can be found in the APT tool, from the main menu under File → JWST Demonstration Proposals → Solar System Example. This example file includes observations of minor bodies, comets, satellites, and giant planets using the instruments and modes most suitable for Solar System programs.
ETC sample workbook and example science program
The Exposure Time Calculator (ETC) provides a Solar System Sample Workbook and an example science program that can be retrieved from the Available Workbooks page (see JWST ETC Using the Sample Workbooks for additional information on how to retrieve these workbooks). These example workbooks provide users with a starting point for creating sources and calculations for planning Solar System observations.
The example science program, NIRSpec IFU and Fixed Slit Observations of Near-Earth Asteroids, provides an end-to-end walkthrough of how to create a Solar System proposal, and the associated ETC workbook is described in detail in the Step-by-Step ETC Guide for NIRSpec IFU and Fixed Slit Observations of Near-Earth Asteroids.
Webcasts and presentation packets (2016 - 2019)
Presentation chart packets from JWST workshops and Townhall events at AAS Division of Planetary Sciences meetings are linked below. They cover in considerable detail topics such as using the Astronomer's Proposal Tool (APT) and Exposure Time Calculator (ETC) for planning observations, tracking capabilities of the observatory, and processing data in the pipeline.
October 16-21, 2016: JWST at the 48th Annual Division for Planetary Sciences (Joint with EPSC) Meeting
February 7, 2017: Solar System Community Webinar: JWST Early Release Science Program
February 14, 2017: JWST Community Lecture Series - Observing Solar System Targets with JWST
November 13-15, 2017: Planning Solar System Observations with JWST - STScI venue
December 13-15, 2017: Planning Solar System Observations with JWST - ESTEC venue
February 13, 2018: Planning Solar System Observations with JWST in Cycle 1
October 21-26, 2018: JWST at the 50th Annual Division for Planetary Sciences Meeting
September 15-20, 2019: JWST at the 51st Annual Division for Planetary Sciences Meeting (Joint with EPSC)
List of articles
JWST Moving Target Observations
- • MT Roadmap
- MT Proposal Planning
- MT Technical Information
Magnum, J., ed. 2016, PASP, 128, 959
Special Issue: Innovative Solar System Science with the James Webb Space Telescope