A Consolidated Grant Proposal for Solar and Planetary Science, 2022 - 2025 Project 8: Observing currents within giant planet ionospheres
Lead Research Organisation:
Northumbria University
Department Name: Fac of Engineering and Environment
Abstract
The past two decades have seen profound changes in our understanding of how aurorae are generated in giant planet atmospheres. Cassini and Juno's measurements of magnetic fields, in the auroral generation regions close to the planet and the far equatorial magnetospheric regions, have revealed complex and often beguiling currents that close into the planet's atmosphere. Highly dynamic images of the aurorae from the Hubble Space Telescope and these spacecraft provide a window into how these currents map into the surrounding space environment, giving us a detailed measure of the auroral flux produced by these currents, along with tantalising hints of their origin.
But, for all this wealth of information, the specific driving forces that power the auroral currents remains controversial. Unfortunately, these spacecraft have no way to measure how these currents close through the ionosphere - the region that is key to understanding how these currents are driven. We propose to utilise our extensive dataset of infrared telescope observations of the giant planets' ionospheres, already collected and reduced by the University of Leicester, to provide direct measurements of the auroral brightness and ion winds over an extended period. Using a proven observing technique that has already produced ground-breaking snapshots of the ionospheres of these planets, we will produce the first-ever long-term auroral current maps organized by local time and planetary phase, allowing a new depth of understanding on how gas giant aurorae are generated. In turn, this will provide vital evidence that will help us answer these key questions that remain unanswered following the Cassini and Juno space missions:
1. What drives Jupiter's main emission, and why is it so dependent upon local time?
2. What processes control Jupiter's polar aurora, and why do they switch off at night?
3. Does Saturn have weather-driven aurora, and does this cause its rotation rate to vary?
But, for all this wealth of information, the specific driving forces that power the auroral currents remains controversial. Unfortunately, these spacecraft have no way to measure how these currents close through the ionosphere - the region that is key to understanding how these currents are driven. We propose to utilise our extensive dataset of infrared telescope observations of the giant planets' ionospheres, already collected and reduced by the University of Leicester, to provide direct measurements of the auroral brightness and ion winds over an extended period. Using a proven observing technique that has already produced ground-breaking snapshots of the ionospheres of these planets, we will produce the first-ever long-term auroral current maps organized by local time and planetary phase, allowing a new depth of understanding on how gas giant aurorae are generated. In turn, this will provide vital evidence that will help us answer these key questions that remain unanswered following the Cassini and Juno space missions:
1. What drives Jupiter's main emission, and why is it so dependent upon local time?
2. What processes control Jupiter's polar aurora, and why do they switch off at night?
3. Does Saturn have weather-driven aurora, and does this cause its rotation rate to vary?
Organisations
- Northumbria University (Lead Research Organisation)
- Tohoku University (Collaboration)
- National Aeronautics and Space Administration (NASA) (Collaboration)
- University College London (Collaboration)
- Johns Hopkins University (Collaboration)
- University of California, Berkeley (Collaboration)
- Boston University (Collaboration)
- International Association for the Philosophy of Sport (IAPS) (Collaboration)
- UNIVERSITY OF READING (Collaboration)
- University of Texas (Collaboration)
- Observatory of Paris (Collaboration)
- Kyunghee University (Collaboration)
- University of Colorado (Collaboration)
People |
ORCID iD |
| Thomas Stallard (Principal Investigator) |
Publications
Hue V
(2024)
The Polar Stratosphere of Jupiter
in Space Science Reviews
Melin H
(2024)
Ionospheric irregularities at Jupiter observed by JWST
in Nature Astronomy
Migliorini A
(2025)
Triton and Pluto - The long lost twins of active worlds
RodrĂguez-Ovalle P
(2024)
Temperature and Composition Disturbances in the Southern Auroral Region of Jupiter Revealed by JWST/MIRI
in Journal of Geophysical Research: Planets
Thomas E
(2023)
Detection of the infrared aurora at Uranus with Keck-NIRSPEC
in Nature Astronomy
Tsubota T
(2024)
UV-dark polar ovals on Jupiter as tracers of magnetosphere-atmosphere connections
in Nature Astronomy
Wang R
(2024)
Simultaneous Infrared Observations of the Jovian Auroral Ionosphere and Thermosphere.
in Journal of geophysical research. Space physics
Wang R
(2023)
Asymmetric Ionospheric Jets in Jupiter's Aurora
in Journal of Geophysical Research: Space Physics
| Description | Keck Travel funding for observations |
| Amount | $6,000 (USD) |
| Organisation | National Aeronautics and Space Administration (NASA) |
| Sector | Public |
| Country | United States |
| Start | 03/2011 |
| End | 03/2026 |
| Title | Cassini/VIMS observations of Jupiter |
| Description | A collated set of observations of Jupiter specifically curated for those observations that measure the auroral region, including reduced data not available on alternative archives. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| Impact | Originally used in a publication in 2015 by our team, this dataset was released at the request of a chinese researcher. We have not yet seen a publication resulting from the dataset. |
| URL | https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/XHS5JG |
| Description | Boston University Imaging Science Team |
| Organisation | Boston University |
| Department | Imaging Science |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | Have provided observing experience, as well as inputs into Jupiter and Saturn aeronomy modelling |
| Collaborator Contribution | Modelling of ionosphere/atmosphere of Jupiter and Saturn, as well as discussions over access to Boston University observatories. Sharing of HST images of Jupiter and Saturn in the UV |
| Impact | Significant enhancement of both observing and modelling. One publication following on from the modelling of Jupiter's equatorward regions. |
| Start Year | 2009 |
| Description | Comparing the thermospheres of Eath and Jupiter |
| Organisation | University of Colorado |
| Department | Colorado Center for Astrodynamics Research (CCAR) |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | We have met and discussed the implications of various energy inputs to Jupiter's ionosphere and thermosphere |
| Collaborator Contribution | They have provided context to these discussions by providing details of how the Earth system reacts to auroral and non-auroral inputs |
| Impact | An invited talk at Colorado, to enhance discussions |
| Start Year | 2015 |
| Description | Exploring the upper stratosphere of Saturn |
| Organisation | Kyunghee University |
| Country | Korea, Republic of |
| Sector | Academic/University |
| PI Contribution | We have provided an analysis of VIMS observations, identifying and describing the methane fluorescence from the upper stratosphere. |
| Collaborator Contribution | They have provided detailed high-resolution spectral measurement, allowing us to identify specific methane emissions within the stratosphere. The have also collaborated with proposed observations, adding significant adacemic weight to the observation request. |
| Impact | Jointly, we are currently working on research that could potentially result in a number of publications, both looking at altitudinal profiles of temperature, and the neutral winds in the upper stratosphere. |
| Start Year | 2014 |
| Description | Ground-based observations and HIRIMS l'Observatoire de Paris |
| Organisation | Observatory of Paris |
| Department | Laboratory for Space Science and Astrophysical Instrumentation |
| Country | France |
| Sector | Charity/Non Profit |
| PI Contribution | We have used observations made by this collaborator in our long term study of Uranus. We are also Co-I status on their proposed JUICE instrument HIRIMS, which remains under negotiation for inclusion into the selected instrument MAJIS. |
| Collaborator Contribution | The provision of observational data of Uranus. PI leadership on instrument proposal. |
| Impact | Our paper on the long-term variability of Uranus. |
| Description | Ground-based observations at University of Texas |
| Organisation | University of Texas |
| Department | Department of Astronomy |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | We have used observations made by this collaborator in our long term study of Uranus. |
| Collaborator Contribution | We have made a significant number of observations and proposals together, allowing a combined access to observations of Saturn and in particular Uranus. |
| Impact | Our paper on the long-term variability of Uranus, as well as significant observing proposals and observations. |
| Description | Hubble and GBO observations of the underlying stratosphere of Jupiter |
| Organisation | University of California, Berkeley |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | I provided detailed discussion and contributed writing to a recent HST observation of the stratosphere, resulting in a successful Nature Astronomy paper. I also visited Berkeley to discuss ongoing research with JWST and potential future JWST proposals. |
| Collaborator Contribution | Berkeley scientists contributed significant leadership in the earlier stages of JWST, provided essential feedback on our successful JWST proposals and contributed the majority of the work done on the Nature Astronomy publication. |
| Impact | Nature Astronomy paper by Tsubota et al, 2024. Contributions to JWST #1665 observations of Jupiter, for Uranus #5073, as well as early drafts of Saturn #5308 |
| Start Year | 2017 |
| Description | IAPS/INAF-Rome |
| Organisation | International Association for the Philosophy of Sport (IAPS) |
| Country | Italy |
| Sector | Charity/Non Profit |
| PI Contribution | Provided ground-based support observations for the JIRAM team, allowing calibration of that instrument using our data as a guide |
| Collaborator Contribution | Have provided significant discussions for both future planning of the observations of JIRAM, and for past observations on Cassini and Galileo |
| Impact | Safeguarded our publications from being trumped by IAPS publications |
| Start Year | 2010 |
| Description | Planetary Atmospheric Physics Lab, Tohoku Univeristy |
| Organisation | Tohoku University |
| Department | Planetary Atmospheric Physics Lab |
| Country | Japan |
| Sector | Academic/University |
| PI Contribution | We are currently collaborating on observations of Jupiter's auroral region. I have successfully been awarded a number of collaborative observing proposals with Tohoku as collaborating co-i's. |
| Collaborator Contribution | We have been included on a number of observing proposals made to Subaru and IRTF. We are also working with TOhoku in the upcoming EXCEED mission, which will look at the UV aurora. |
| Impact | Our observation proposals have been strengthened by the collaboration, and we will have access to the EXCEED dataset. |
| Start Year | 2012 |
| Description | Planetary aurora, and the effect of solar wind |
| Organisation | University of Reading |
| Department | Department of Meteorology |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | A recent visit to the organisation, with specific discussions of how to better apply SW modelling to the outer solar system. |
| Collaborator Contribution | Provision of SW modelling in developing papers for publication. |
| Impact | None yet. |
| Start Year | 2024 |
| Description | UCL observation team |
| Organisation | University College London |
| Department | Department of Physics & Astronomy |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | In collaborating on both the observation, reduction, analysis and scientific output from our combined research, we have made significant advances that would not have been possible by one individual team. We have worked on the majority of the observations, from inception to completion, including reduction and have shared in the analysis of this data. |
| Collaborator Contribution | Observations to major telescopes have been co-written with astronomers at UCL, providing a joint research depth that has significantly improved our observational outcomes. |
| Impact | We have produce a significant amount of work using ground-based observations, some still in analysis, and have produced papers studying Saturn, Uranus and Neptune based on observations that come from this collaboration. In particular, the Uranus paper was produced using observations covering 16 years of observations, many made by the UCL team. |
| Description | Uranus space mission planning at Goddard |
| Organisation | Johns Hopkins University |
| Department | Applied Physics Laboratory (APL) |
| Country | United States |
| Sector | Charity/Non Profit |
| PI Contribution | I've been asked to work with both Goddard and APL to start considering potential science objectives for the upcoming Uranus mission. |
| Collaborator Contribution | They will host me at Goddard this year. |
| Impact | No outcomes yet. |
| Start Year | 2025 |
| Description | Uranus space mission planning at Goddard |
| Organisation | National Aeronautics and Space Administration (NASA) |
| Department | Goddard Space Flight Center |
| Country | United States |
| Sector | Public |
| PI Contribution | I've been asked to work with both Goddard and APL to start considering potential science objectives for the upcoming Uranus mission. |
| Collaborator Contribution | They will host me at Goddard this year. |
| Impact | No outcomes yet. |
| Start Year | 2025 |
| Description | Uranus space mission planning at JPL |
| Organisation | National Aeronautics and Space Administration (NASA) |
| Department | Jet Propulsion Laboratory |
| Country | United States |
| Sector | Public |
| PI Contribution | I visited JPL to discuss thermospheric changes and how we might monitor these with a space mission, as a part of a closed meeting to help JPL plan for upcoming proposals for Uranus mission. |
| Collaborator Contribution | They paid for flights and hotel to Pasadena for a week |
| Impact | No outcomes yet. |
| Start Year | 2022 |
| Description | Eyeing the Ionosphere: Juno, JWST, and Jupiter |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | A live broadcast while observing on JWST, Keck and Juno, over multiple days, with the RAS. |
| Year(s) Of Engagement Activity | 2023 |
| URL | https://www.youtube.com/watch?v=uk1n9XaF3z0 |
| Description | Livestreaming observations of Uranus with the RAS |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | We hosted a live observation event with the RAS, livecasting our observations |
| Year(s) Of Engagement Activity | 2021 |
| URL | https://www.youtube.com/watch?v=bBqYso9RDSs&pp=ygUPcmFzIHVyYW51cyBsaXZl |