Exoplanets in 3D: Interpreting 3D planets using 1D spectra
Lead Research Organisation:
The Open University
Department Name: Faculty of Sci, Tech, Eng & Maths (STEM)
Abstract
Satellite images of the planets in our Solar System reveal dynamic, changing worlds. Jupiter's poles are now known to be unexpectedly blue, contrasting with the equator, and the great red spot is gradually shrinking. Recently, we have also started to find out more about planets orbiting other stars - exoplanets. Studying exoplanets is exciting because it provides context for the evolution of Solar System planets, but also involves several challenges.
Only rarely can we directly observe an exoplanet, because stars are so much larger and brighter. Instead, we measure the dip in the amount of light coming from the parent star when the planet passes in front. Gases and cloud particles absorb and scatter particular colours - or wavelengths - of light, so by measuring precisely the amount of light blocked by the planet at each wavelength, we can identify the unique fingerprints of substances in the planet's atmosphere - all without seeing the planet!
However, there's a catch: we only get a single measurement averaged over the whole of the planet's visible atmosphere, which is not uniform and changes with time. To truly compare exoplanets with Solar System worlds, we need to understand what this average measurement actually represents. I aim to investigate, using computational models of light passing through an atmosphere, how a 3D, time-varying, cloudy exoplanet atmosphere can best be studied using these measurements. I will compare models with data from the new James Webb Space Telescope, due to be launched in 2021, which is set to provide the most detailed and precise observations of exoplanets yet.
Only rarely can we directly observe an exoplanet, because stars are so much larger and brighter. Instead, we measure the dip in the amount of light coming from the parent star when the planet passes in front. Gases and cloud particles absorb and scatter particular colours - or wavelengths - of light, so by measuring precisely the amount of light blocked by the planet at each wavelength, we can identify the unique fingerprints of substances in the planet's atmosphere - all without seeing the planet!
However, there's a catch: we only get a single measurement averaged over the whole of the planet's visible atmosphere, which is not uniform and changes with time. To truly compare exoplanets with Solar System worlds, we need to understand what this average measurement actually represents. I aim to investigate, using computational models of light passing through an atmosphere, how a 3D, time-varying, cloudy exoplanet atmosphere can best be studied using these measurements. I will compare models with data from the new James Webb Space Telescope, due to be launched in 2021, which is set to provide the most detailed and precise observations of exoplanets yet.
Publications
Ahrer EM
(2023)
Early Release Science of the exoplanet WASP-39b with JWST NIRCam.
in Nature
Alderson L
(2023)
Early Release Science of the exoplanet WASP-39b with JWST NIRSpec G395H.
in Nature
Banerjee A
(2023)
Effect of centrifugal force on transmission spectroscopy of exoplanet atmospheres
in Monthly Notices of the Royal Astronomical Society: Letters
Banerjee A
(2024)
Atmospheric Retrievals Suggest the Presence of a Secondary Atmosphere and Possible Sulfur Species on L98-59 d from JWST Nirspec G395H Transmission Spectroscopy
in The Astrophysical Journal Letters
Barstow J
(2021)
The curse of clouds
in Astronomy & Geophysics
Barstow M
(2021)
The search for living worlds and the connection to our cosmic origins
in Experimental Astronomy
Bell TJ
(2024)
Nightside clouds and disequilibrium chemistry on the hot Jupiter WASP-43b.
in Nature astronomy
Boehm V
(2024)
The HUSTLE Program: The UV to Near-infrared HST WFC3/UVIS G280 Transmission Spectrum of WASP-127b
in The Astronomical Journal
Chubb K
(2024)
Data availability and requirements relevant for the Ariel space mission and other exoplanet atmosphere applications
in RAS Techniques and Instruments
| Description | BOWIE |
| Organisation | Imperial College London |
| Department | Department of Physics |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | I provide retrieval simulations and modelling specific/solar system related advice during planning and preparation of observing proposals for JWST. |
| Collaborator Contribution | BOWIE is a consortium for collectively planning and preparing observing proposals for JWST. People within the linked research groups provide their specific expertise (for example, experience with the APT proposal tool, experience with analysing certain types of data, etc.) and contribute towards multiple proposals. |
| Impact | I am a co-investigator on 6 cycle 3 proposals, of which I am co-PI for one. |
| Start Year | 2023 |
| Description | BOWIE |
| Organisation | University of Bristol |
| Department | School of Physics |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | I provide retrieval simulations and modelling specific/solar system related advice during planning and preparation of observing proposals for JWST. |
| Collaborator Contribution | BOWIE is a consortium for collectively planning and preparing observing proposals for JWST. People within the linked research groups provide their specific expertise (for example, experience with the APT proposal tool, experience with analysing certain types of data, etc.) and contribute towards multiple proposals. |
| Impact | I am a co-investigator on 6 cycle 3 proposals, of which I am co-PI for one. |
| Start Year | 2023 |
| Description | BOWIE |
| Organisation | University of Exeter |
| Department | School of Physics |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | I provide retrieval simulations and modelling specific/solar system related advice during planning and preparation of observing proposals for JWST. |
| Collaborator Contribution | BOWIE is a consortium for collectively planning and preparing observing proposals for JWST. People within the linked research groups provide their specific expertise (for example, experience with the APT proposal tool, experience with analysing certain types of data, etc.) and contribute towards multiple proposals. |
| Impact | I am a co-investigator on 6 cycle 3 proposals, of which I am co-PI for one. |
| Start Year | 2023 |
| Description | BOWIE |
| Organisation | University of Leicester |
| Department | Department of Physics & Astronomy |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | I provide retrieval simulations and modelling specific/solar system related advice during planning and preparation of observing proposals for JWST. |
| Collaborator Contribution | BOWIE is a consortium for collectively planning and preparing observing proposals for JWST. People within the linked research groups provide their specific expertise (for example, experience with the APT proposal tool, experience with analysing certain types of data, etc.) and contribute towards multiple proposals. |
| Impact | I am a co-investigator on 6 cycle 3 proposals, of which I am co-PI for one. |
| Start Year | 2023 |
| Description | BOWIE |
| Organisation | University of Oxford |
| Department | Department of Physics |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | I provide retrieval simulations and modelling specific/solar system related advice during planning and preparation of observing proposals for JWST. |
| Collaborator Contribution | BOWIE is a consortium for collectively planning and preparing observing proposals for JWST. People within the linked research groups provide their specific expertise (for example, experience with the APT proposal tool, experience with analysing certain types of data, etc.) and contribute towards multiple proposals. |
| Impact | I am a co-investigator on 6 cycle 3 proposals, of which I am co-PI for one. |
| Start Year | 2023 |
| Description | BOWIE |
| Organisation | University of Warwick |
| Department | Department of Physics |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | I provide retrieval simulations and modelling specific/solar system related advice during planning and preparation of observing proposals for JWST. |
| Collaborator Contribution | BOWIE is a consortium for collectively planning and preparing observing proposals for JWST. People within the linked research groups provide their specific expertise (for example, experience with the APT proposal tool, experience with analysing certain types of data, etc.) and contribute towards multiple proposals. |
| Impact | I am a co-investigator on 6 cycle 3 proposals, of which I am co-PI for one. |
| Start Year | 2023 |
| Description | Article for The Conversation |
| Form Of Engagement Activity | A magazine, newsletter or online publication |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I was approached to write an article on free-floating planets for The Conversation. The opportunity is provided for comment and further engagement below the article. |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://theconversation.com/rogue-planets-how-wandering-bodies-in-interstellar-space-ended-up-on-the... |
| Description | Article for The Conversation - 4 ways JWST might detect evidence for alien life |
| Form Of Engagement Activity | A magazine, newsletter or online publication |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I was approached by The Conversation to write an article about biosignature detection with the James Webb Space Telescope. This allowed me to describe possible signals we could find that might hint at extraterrestrial life, while also being clear that the burden of proof for this is extremely high and many biosignatures have false positives. The response to this article prompted Dr Becky to invite me onto her YouTube channel to discuss it further. I also received an interview request from Talk Radio Cape Town. |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://theconversation.com/four-ways-to-spot-hints-of-alien-life-using-the-james-webb-space-telesco... |
| Description | Article for The Conversation - James Webb Space Telescope uncovers secrets of distant world |
| Form Of Engagement Activity | A magazine, newsletter or online publication |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I pitched and wrote a piece for The Conversation about the first results from our James Webb Space Telescope Transiting Exoplanet Community Early Release Science programme. This helped to disseminate results from our five papers and enhanced the impact of our research. |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://theconversation.com/james-webb-space-telescope-uncovers-chemical-secrets-of-distant-world-pa... |
| Description | Article for The Conversation - WASP-121b |
| Form Of Engagement Activity | A magazine, newsletter or online publication |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I pitched and wrote an article for The Conversation on the paper for which I was a co-author looking at the phase curve and dark side of WASP-121b. |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://theconversation.com/ruby-clouds-and-water-behaving-strangely-what-we-found-when-studying-an-... |
| Description | Expert comment to media on publication of JWST ERS results |
| Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I responded to media enquiries relating to publication of our JWST Early Release Science data. I was quoted in the Guardian in August and gave an interview for BBC 3 Counties radio in November. |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://www.theguardian.com/science/2022/aug/25/webb-telescope-zooms-in-on-planet-beyond-our-solar-s... |
| Description | Guardian WASP-107b interview |
| Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Media (as a channel to the public) |
| Results and Impact | I was approached to provide expert comment on a paper released in Nature that claimed to have found silicate clouds in the atmosphere of a warm Neptune exoplanet. I discussed how 'fluffy' low density planets are excellent targets for JWST due to the size of the signal. |
| Year(s) Of Engagement Activity | 2023 |
| URL | https://www.theguardian.com/science/2023/nov/15/planet-where-it-rains-sand-revealed-by-nasa-telescop... |
| Description | Guardian/Observer JWST interview |
| Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Media (as a channel to the public) |
| Results and Impact | I was approached for comment by the Guardian/Observer Science Robin McKie as he was writing a piece looking at likely exoplanet-related discoveries for JWST over the next year. The piece went out on Christmas Eve in the Observer in honour of the 2-year anniversary of the launch of JWST. We discussed the prospects for observing habitable/Earthlike planets and how high the burden of proof is for claims of extraterrestrial life. |
| Year(s) Of Engagement Activity | 2023 |
| URL | https://www.theguardian.com/science/2023/dec/23/how-the-james-webb-telescope-is-set-to-find-strange-... |
| Description | Interview for Dr Becky's YouTube channel on JWST and biosignature detection |
| Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I was interviewed by astronomer and YouTuber Dr Becky for her channel about the article I had written on using JWST to detect signs of alien life. We also discussed other JWST observations I am involved in. |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://www.youtube.com/watch?v=QWTtN3NQ1Tc |
| Description | Interview for the Guardian on TOI-270d |
| Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I was interviewed by the Guardian as an external expert about work published by two other teams on the sub-Neptune exoplanet TOI-270d. |
| Year(s) Of Engagement Activity | 2024 |
| URL | https://www.theguardian.com/science/2024/mar/08/astronomers-detect-waterworld-with-a-boiling-ocean-i... |
| Description | Interview with Fraser Cain |
| Form Of Engagement Activity | Engagement focused website, blog or social media channel |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I was interviewed by Fraser Cain, host of the Universe Today podcast, about my research on exoplanet atmospheres. So far the interview has over 4.5k views on YouTube and is also being disseminated via Apple podcasts. Viewers who commented expressed interest in the subject matter, and stated that they had learned from the interview. |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://www.youtube.com/watch?v=DHHo0NpdhZ8 |
| Description | Physics Magazine interview on K2-18b |
| Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Media (as a channel to the public) |
| Results and Impact | I was approached for comment on a paper that had claimed the detection of dimethyl sulphide in an exoplanet atmosphere, and was quoted in the resulting article. I discussed the nuances of the claimed detection, how dependent it is on treatment of the data, and how careful we need to be when linking detection of certain chemicals to any mention of extraterrestrial life. |
| Year(s) Of Engagement Activity | 2023 |
| URL | https://physics.aps.org/articles/v16/178 |
| Description | Press release on the phase curve of WASP-43b |
| Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I was quoted in the official press release for the paper on mapping the chemistry and temperature on hot Jupiter WASP-43b, which was picked up by multiple news outlets |
| Year(s) Of Engagement Activity | 2024 |
| URL | https://webbtelescope.org/contents/news-releases/2024/news-2024-117 |
| Description | Public talk at the UK Exoplanet Meeting |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Public/other audiences |
| Results and Impact | I was invited to deliver the public lecture at the UK Exoplanet Meeting in 2024. I gave a talk on How to be an Exoplanet Detective. This led to conversations afterwards, most notably with aspiring young physicists who I was able to advise on their future study. |
| Year(s) Of Engagement Activity | 2024 |
| Description | RAS International Day of Women and Girls in Science Talk |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Public/other audiences |
| Results and Impact | I gave a lunchtime public talk about my research as part of the Royal Astronomical Society's series on women in astronomy. |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://www.youtube.com/watch?v=qM2joewCAvU&t=3s |
| Description | Royal Society Summer Science Exhibition - James Webb Space Telescope:Â First Years of Discovery |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Public/other audiences |
| Results and Impact | I was part of a team exhibiting on JWST's First Years at the Royal Society Summer Exhibition. I designed an interactive jigsaw demo showcasing some of my recent results from JWST data, and participated on several days of the exhibition interacting with the public. |
| Year(s) Of Engagement Activity | 2024 |
| URL | https://stephenwilkins.co.uk/jwsts-first-years/? |
| Description | School visit (Bishop Winnington Ingram) |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | I visited my daughter's reception class at her school to speak to the children about planets, during their topic on the Solar System. I read them a story about an alien visiting the Solar System and answered their questions about planets. I helped them to make a planet out of modelling material. |
| Year(s) Of Engagement Activity | 2021 |
| Description | Talk Radio Cape Town interview about detecting biosignatures. |
| Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | I was interviewed on Talk Radio Cape Town (South Africa) to follow up on my article for The Conversation about finding alien life using JWST. I discussed how feasible that is likely to be, what JWST can tell us, and where we should be ideally looking if we want to find alien life. |
| Year(s) Of Engagement Activity | 2022 |
| Description | Zoom an astronomer chats with Turkish school students |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Schools |
| Results and Impact | I participated in Zoom Q&A sessions with female students studying English at a school in Turkey. They were interested in the topic of space and used it as an opportunity to practise their English language skills. The students became more engaged with astronomy and some expressed an interest in studying it in the future, when they had not done so before. |
| Year(s) Of Engagement Activity | 2022 |