I am thrilled to announce my second PhD paper, under the supervision of Luan Ghezzi, Kevin Heng, and Chloe Fisher 🪐📄 This study is a summary of my PhD thesis (2019–2024), where we analysed retrievals of HST WFC3 transmission spectra and parameter degeneracies associated with them. Read more ⬇️ - ThreadSky

alinenovais.com • 7 days ago

I am thrilled to announce my second PhD paper, under the supervision of Luan Ghezzi, Kevin Heng, and Chloe Fisher 🪐📄

This study is a summary of my PhD thesis (2019–2024), where we analysed retrievals of HST WFC3 transmission spectra and parameter degeneracies associated with them.

Read more ⬇️

Comments

alinenovais.com•7 days ago

This study thoroughly analysed different retrieval models and the degeneracies between individual retrieved parameters, in particular the temperature, abundance of water, and cloud-top pressure level.

We analyse the influence of model parameters, both individually and the ambiguities between them.

alinenovais.com•7 days ago

When performing retrievals on a 38-planet dataset, we noticed some common issues, e.g. how the retrieved temperatures are much lower than the equilibrium values expected for each planet, consequently affecting other degenerate parameters (water abundances, cloud-top pressures).

alinenovais.com•7 days ago

We performed additional temperature tests using three well-known case studies (HD 209458b, WASP-12b, and WASP-39b) to further investigate the low temperature ‘problem’, which is also seen in other retrieval studies.

alinenovais.com•7 days ago

We concluded these low temperatures could have different explanations, e.g. 3D effects, the limites wavelength coverage (affecting the measurement of the scale height), the narrow and high-altitude pressure region probed by WFC3, or even data quality.

alinenovais.com•7 days ago

In a comparison with literature results, we noticed each result has a strong dependence on the model properties and assumption chosen for that particular retrieval, e.g. T-P profiles, inclusion of Rayleigh scattering, collision-induced absorption (CIA), and cloud parameterisation.

alinenovais.com•7 days ago

In addition, some of these literature studies also used different data reductions and/or included wider-wavelength data (HST STIS, Spitzer IRAC).

We performed tests using different data reductions and data coverage, which caused considerable differences in the retrieval results, as expected.

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