How to accurately measure spin-orbit angles in planetary systems

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• Matthew Hooton (Cambridge)
• Tuesday 24 May 2022, 13:00-14:00
• Ryle seminar room + ONLINE - Details to be sent by email.

If you have a question about this talk, please contact Dr Annelies Mortier.

A full understanding the processes that drive the formation and evolution of planetary systems requires observational data that spans the full range of stellar types. In particular, a measurement of the spin-orbit angle (often known as the stellar obliquity) helps us to understand the transfer of angular momentum between star and planets during formation. This talk will introduce the main methods used to measure spin-orbit angles, with a particular emphasis on the extra information that stellar rotation-induced gravity darkening encodes in transit light curves. In theory, this method provides a silver bullet to independently derive the true spin-orbit angle Ψ: a parameter that eludes measurement using most other methods. In practice, an accurate measurement of Ψ using from a transit is challenging, with numerous values for individual planets in literature exhibiting significant disagreement. Doppler tomography provides an alternative spectroscopic method which is less prone to bias, but only unlocks the sky-projected spin-orbit angle λ. I will finish by presenting analyses of transit light curves for a couple of hot Jupiters with fast-rotating hosts acquired with CHEOPS , TESS, Kepler and Spitzer, and put forward a set of recommendations to robustly measure Ψ using both Doppler tomography and mutli-colour transit photometry.

This talk is part of the Exoplanet Seminars series.

This talk is included in these lists:

• Cambridge Astronomy Talks
• Combined External Astrophysics Talks DAMTP
• Cosmology, Astrophysics and General Relativity
• Exoplanet Seminars
• Institute of Astronomy Talk Lists
• LCLU Departmental Talks
• Ryle seminar room + ONLINE - Details to be sent by email

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