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Modelling orbits to detect exoplanets

Thursday, March 28, 2024 - 11:00 to 12:00
William Thompson, Herzberg Instrument Science Fellow, National Research Council of Canada, Herzberg Astronomy and Astrophysics Research Centre
Statistics Seminar
ESB 4192 / Zoom

To join this seminar virtually: Please request Zoom connection details from ea [at] stat.ubc.ca.

Abstract: Determining the orbits of planets is one of the earliest applications of modern science, though nowadays our focus has turned outwards from our solar system to exoplanets orbiting distant stars. To detect and study these planets, we must combine sparse evidence from a variety of sources---direct images of exoplanetary systems, radial velocity curves, interferometer visibilities, transits, and more---to model their physical and orbital parameters. Unfortunately for us, these models can lead to very challenging posteriors that are unidentifiable, multimodal, and can have strong curvature. I will discuss these modelling challenges and present our successes from applying modern sampling techniques (gradient based samplers, and non-reversible parallel tempering) which reduce sampling time from days to seconds, and will enable us to find new exoplanets.