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SUMMARY:How to accurately measure spin-orbit angles in planetary systems -
  Matthew Hooton (Cambridge)
DTSTART:20220524T120000Z
DTEND:20220524T130000Z
UID:TALK172964@talks.cam.ac.uk
CONTACT:Dr Annelies Mortier
DESCRIPTION:A full understanding the processes that drive the formation an
 d evolution of planetary systems requires observational data that spans th
 e full range of stellar types. In particular\, a measurement of the spin-o
 rbit angle (often known as the stellar obliquity) helps us to understand t
 he transfer of angular momentum between star and planets during formation.
  This talk will introduce the main methods used to measure spin-orbit angl
 es\, with a particular emphasis on the extra information that stellar rota
 tion-induced gravity darkening encodes in transit light curves. In theory\
 , this method provides a silver bullet to independently derive the true sp
 in-orbit angle Ψ: a parameter that eludes measurement using most other me
 thods. In practice\, an accurate measurement of Ψ using from a transit is
  challenging\, with numerous values for individual planets in literature e
 xhibiting significant disagreement. Doppler tomography provides an alterna
 tive spectroscopic method which is less prone to bias\, but only unlocks t
 he 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 h
 osts acquired with CHEOPS\, TESS\, Kepler and Spitzer\, and put forward a 
 set of recommendations to robustly measure Ψ using both Doppler tomograph
 y and mutli-colour transit photometry.\n\n
LOCATION:Ryle seminar room + ONLINE - Details to be sent by email
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