A deep radius valley revealed by Kepler short cadence observations

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• Cynthia Ho (UCL)
• Tuesday 15 November 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 Emily Sandford.

The characteristics of the radius valley, i.e., an observed lack of planets between 1.5-2 Earth radii at periods shorter than about 100 days, provide insights into the formation and evolution of close-in planets. In this talk, I present a novel view of the radius valley by refitting the transits of over 400 planets using Kepler 1-minute short cadence observations, the vast majority of which have not been previously analysed in this way. In some cases, the updated planetary parameters differ significantly from previous studies, resulting in a deeper radius valley than previously observed. This suggests that planets are likely to have a more homogeneous core composition at formation. Furthermore, using support-vector machines, I show that the radius valley location depends on orbital period, stellar mass, and stellar age. These findings favour thermally-driven mass loss models such as photoevaporation and core-powered mass loss, with a slight preference for the latter scenario. Finally, I will highlight the value of transit observations with short photometric cadence to precisely determine planet radii.

This talk is part of the Exoplanet Seminars series.

This talk is included in these lists:

• 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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