Astronomy Colloquium

Wednesday, January 18, 2023

4:00pm to 5:00pm

Cahill, Hameetman Auditorium

Where There's a Wobble There's a Way: New Astrophysical Insights from Pulsating Stars (and Planets)

Jim Fuller, Assistant Professor of Theoretical Astrophysics, TAPIR, California Institute of Technology,

A renaissance in stellar astrophysics is underway, with key developments stemming from asteroseismology. Within our own solar system, pulsations of Saturn have been detected using its rings. An asteroseismic analysis reveals the presence of a large and diffuse planetary core, in contrast to canonical planetary models. Saturn's moons can lock into resonance with the planet's pulsations, driving the observed outward migration of its largest moon, Titan. In red giant stars, pulsations can pinpoint unusual stars that have undergone stellar mergers. The pulsations also allow for measurements of core spin rates, informing new angular momentum transport models arising from magnetic instabilities. Extended to more evolved stars, these models may explain the slow observed rotation rates of white dwarfs, neutron stars, and black holes. An exception occurs for helium stars tidally spun up in binaries, sometimes allowing for highly spinning magnetars and black holes capable of driving energetic transients.

To view this talk via YouTube, please visit https://www.youtube.com/playlist?list=PLb1880Rn0qkKFkWyROUq1kRlgCsuBTrnd

For more information, please contact Dimitri Mawet by email at [email protected] or visit http://www.astro.caltech.edu.

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