Water world Exoplanets: Atmospheric Characterisation with James Webb Space Telescope
PhD Scholarship
Use James Webb Space Telescope observations to study exoplanet atmospheres, focusing on the most promising water world candidates. Develop new methods to disentangle planetary signals from instrumental artefacts and stellar noise.
Water worlds represent an exciting frontier in astronomy, having long been theorised to bridge the gap between rocky planets and larger ice giants. By mass, water worlds are hypothesised to be composed of 10–90% water and other volatile ices, such as ammonia and methane, with the remainder being made up of silicates and iron. In contrast, the rocky planets of the solar system are extremely ‘dry’—for example, despite having a surface covered by oceans, water constitutes less than 0.1% of the Earth’s total mass. Meanwhile, the ice giants Uranus and Neptune have thick outer envelopes composed of hydrogen-rich gas, whereas water worlds would be devoid of hydrogen.
Current models predict that water worlds should frequently form in protoplanetary disks but empirically confirming this is crucial. The only way to unambiguously determine if a planet is a water world is by measuring its atmospheric chemical composition, which until recently has been beyond the reach of humanity’s best telescopes. However, this changed in 2022 with the successful deployment of the James Webb Space Telescope (JWST), which has now observed more than 150 exoplanets, including numerous water world candidates. This project will focus on analysing JWST datasets to identify and characterise the atmospheric properties of water worlds.
Key objectives
- Analyse JWST observations of sub-Neptune exoplanets, with a focus on the most promising water world candidates.
- Develop analysis techniques to disentangle planetary signals from instrumental artefacts and stellar noise.
- Perform atmospheric retrieval analyses to infer chemical compositions and temperatures from exoplanet spectra.
- Determine the frequency of water worlds and compare results to predictions of planet formation theories.
- Evaluate the prospects for water world habitability.
PhD Scholarship details
Funding: $36,000 per annum, as well as a top-up stipend of $3,778 p.a. For a PhD candidate, the living allowance scholarship and tuition fee scholarship are for 3.5 years. Scholarships also include up to $1,500 relocation allowance.
Supervisor: Tom Evans-Soma
Available to: Domestic students
PhD
Eligibility Criteria
The applicant will need to meet the minimum eligibility criteria for admission.
Application Procedure
Interested applicants should send an email expressing their interest along with scanned copies of their academic transcripts, CV, a brief statement of their research interests and a proposal that specifically links them to the research project.
Please send the email expressing interest to Tom.Evans-Soma@newcastle.edu.au by 5pm on 03 June 2026.
Applications Close 03 June 2026 Apply Now
- Contact: Tom Evans-Soma
- Phone: +61 2 4055 3229
- Email: Tom.Evans-Soma@newcastle.edu.au
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