Jon Sundqvist (KU Leuven): Superstars: finally in 3D

Thursday 12 May 2022, 14:00 → 15:00 Europe/Stockholm

https://uu-se.zoom.us/j/62091586806

Title: Superstars: finally in 3D
Speaker: Jon Sundqvist
Affiliation: KU Leuven
Time: Thursday 12 May 2022, 1400 to 1500
Location: online at https://uu-se.zoom.us/j/62091586806

Abstract:

Observations and theory show that the radiation-dominated envelopes and atmospheres of massive stars are highly complex, time-variable, and multi-dimensional systems. However, whereas 3D model atmospheres of sun-like stars have already been on the market for a while, for hot, massive stars we still rely solely on results derived from inadequate 1D simulations.

In this talk I will discuss ongoing efforts to make this long-awaited 1D -> 3D transition in the simulation and spectral analysis of massive stars, discuss why it's important to finally do so, and also perhaps comment on why it seems to have taken so much longer than for the lower-mass stars studied extensively in Uppsala.

We'll further discuss how instabilities in the most luminous stars likely cause their envelopes to be highly turbulent and unsteady, and comment on how this might have severe implications for massive-star predictions not only today, but (speculatively) also for the (speculative) existence/stability of the Supermassive First Stars believed to be critical agents in cosmic reionisation as well as potential seeds of the supermassive black holes observed at very high redshifts.