Characterising exoplanets in reflected light: a pathway towards Earth-like worlds
<p>The study of the reflected light of exoplanets and the insights it provides on their atmospheres is a poorly developed but crucial avenue of research in exoplanet characterisation. It will be key in characterising nearby potentially Earth-like worlds due to their low temperatures and low tr...
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| Format: | Thesis |
| Language: | English |
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2024
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| _version_ | 1817931518611292160 |
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| author | Vaughan, SR |
| author2 | Birkby, J |
| author_facet | Birkby, J Vaughan, SR |
| author_sort | Vaughan, SR |
| collection | OXFORD |
| description | <p>The study of the reflected light of exoplanets and the insights it provides on their atmospheres is a poorly developed but crucial avenue of research in exoplanet characterisation. It will be key in characterising nearby potentially Earth-like worlds due to their low temperatures and low transit probability. The upcoming Extremely Large Telescopes will offer the first opportunities to characterise nearby, potentially Earth-like worlds but will require high spectral resolution to make robust detections. However, the reflected light of an exoplanet has never been detected at high spectral resolution, therefore this thesis lays the ground work for proving this technique.</p>
<p>High-resolution reflection spectra have been sought for several hot Jupiters, however robust measurements have not been made due to their low reflectivity. To prove the High-Resolution Cross-Correlation Spectroscopy (HRCCS) technique for extracting high-resolution spectra in reflected light, I first present an ongoing a study of the highly reflective planet LTT-9779 b using the world's largest optical telescope i.e. ESPRESSO@VLT in 4UT mode. I have not made a robust detection of the planet's reflected light yet, which suggests the presence of a high cloud deck, however, there is a tentative but promising signal in the post-eclipse data.</p>
<p>A similar high-spectral resolution technique, known as molecule mapping, could leverage the spatial resolution of the Extremely Large Telescope (ELT) to study some of the first potentially Earth-like planets in reflected light. To anticipate the capabilities of the instrument HARMONI@ELT. I simulated realistic observations of Proxima b, the nearest potentially Earth-like exoplanet. It is suitable for characterisation with HARMONI, however, the instrument's focal plane mask will obscure the planet's entire orbit. If the focal plane mask were to be shrunk or offset then I show that biosignature detection on Proxima b could be possible with around 40 hours of observation.</p>
<p>Looking further into the future, missions like the Habitable Worlds Observatory will enable the characterisation of potentially dozens of potentially Earth-like worlds and might even detect liquid water. However, the detection of liquid water requires the planet to be observed at small separations from its star. In this thesis, I show how the size of the unobservable region behind the coronagraph strongly impacts the number of systems where scattering phenomena that can be used to detect liquid water, such as rainbows and ocean glint, can be observed. Thus giving an initial indication of the viability of observing such phenomena.</p>
<p>Characterisation through reflected light is a promising and exciting research area and the coming decades are expected to see significant advancements in this field. This thesis lays out a roadmap to the characterization of habitable worlds using reflected light and where this research might take us in the next few decades.</p> |
| first_indexed | 2024-12-09T03:23:18Z |
| format | Thesis |
| id | oxford-uuid:fb0bbe21-0779-449b-a640-84943ba5df30 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-12-09T03:23:18Z |
| publishDate | 2024 |
| record_format | dspace |
| spelling | oxford-uuid:fb0bbe21-0779-449b-a640-84943ba5df302024-11-14T08:58:14ZCharacterising exoplanets in reflected light: a pathway towards Earth-like worldsThesishttp://purl.org/coar/resource_type/c_db06uuid:fb0bbe21-0779-449b-a640-84943ba5df30Extrasolar planetsEnglishHyrax Deposit2024Vaughan, SRBirkby, J<p>The study of the reflected light of exoplanets and the insights it provides on their atmospheres is a poorly developed but crucial avenue of research in exoplanet characterisation. It will be key in characterising nearby potentially Earth-like worlds due to their low temperatures and low transit probability. The upcoming Extremely Large Telescopes will offer the first opportunities to characterise nearby, potentially Earth-like worlds but will require high spectral resolution to make robust detections. However, the reflected light of an exoplanet has never been detected at high spectral resolution, therefore this thesis lays the ground work for proving this technique.</p> <p>High-resolution reflection spectra have been sought for several hot Jupiters, however robust measurements have not been made due to their low reflectivity. To prove the High-Resolution Cross-Correlation Spectroscopy (HRCCS) technique for extracting high-resolution spectra in reflected light, I first present an ongoing a study of the highly reflective planet LTT-9779 b using the world's largest optical telescope i.e. ESPRESSO@VLT in 4UT mode. I have not made a robust detection of the planet's reflected light yet, which suggests the presence of a high cloud deck, however, there is a tentative but promising signal in the post-eclipse data.</p> <p>A similar high-spectral resolution technique, known as molecule mapping, could leverage the spatial resolution of the Extremely Large Telescope (ELT) to study some of the first potentially Earth-like planets in reflected light. To anticipate the capabilities of the instrument HARMONI@ELT. I simulated realistic observations of Proxima b, the nearest potentially Earth-like exoplanet. It is suitable for characterisation with HARMONI, however, the instrument's focal plane mask will obscure the planet's entire orbit. If the focal plane mask were to be shrunk or offset then I show that biosignature detection on Proxima b could be possible with around 40 hours of observation.</p> <p>Looking further into the future, missions like the Habitable Worlds Observatory will enable the characterisation of potentially dozens of potentially Earth-like worlds and might even detect liquid water. However, the detection of liquid water requires the planet to be observed at small separations from its star. In this thesis, I show how the size of the unobservable region behind the coronagraph strongly impacts the number of systems where scattering phenomena that can be used to detect liquid water, such as rainbows and ocean glint, can be observed. Thus giving an initial indication of the viability of observing such phenomena.</p> <p>Characterisation through reflected light is a promising and exciting research area and the coming decades are expected to see significant advancements in this field. This thesis lays out a roadmap to the characterization of habitable worlds using reflected light and where this research might take us in the next few decades.</p> |
| spellingShingle | Extrasolar planets Vaughan, SR Characterising exoplanets in reflected light: a pathway towards Earth-like worlds |
| title | Characterising exoplanets in reflected light: a pathway towards Earth-like worlds |
| title_full | Characterising exoplanets in reflected light: a pathway towards Earth-like worlds |
| title_fullStr | Characterising exoplanets in reflected light: a pathway towards Earth-like worlds |
| title_full_unstemmed | Characterising exoplanets in reflected light: a pathway towards Earth-like worlds |
| title_short | Characterising exoplanets in reflected light: a pathway towards Earth-like worlds |
| title_sort | characterising exoplanets in reflected light a pathway towards earth like worlds |
| topic | Extrasolar planets |
| work_keys_str_mv | AT vaughansr characterisingexoplanetsinreflectedlightapathwaytowardsearthlikeworlds |