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Title: Schwarzschild and Ledoux are Equivalent on Evolutionary Timescales
Abstract

Stellar evolution models calculate convective boundaries using either the Schwarzschild or Ledoux criterion, but confusion remains regarding which criterion to use. Here we present a 3D hydrodynamical simulation of a convection zone and adjacent radiative zone, including both thermal and compositional buoyancy forces. As expected, regions that are unstable according to the Ledoux criterion are convective. Initially, the radiative zone adjacent to the convection zone is Schwarzschild unstable but Ledoux stable due to a composition gradient. Over many convective overturn timescales, the convection zone grows via entrainment. The convection zone saturates at the size originally predicted by the Schwarzschild criterion, although in this final state the Schwarzschild and Ledoux criteria agree. Therefore, the Schwarzschild criterion should be used to determine the size of stellar convection zones, except possibly during short-lived evolutionary stages in which entrainment persists.

Authors:
; ; ; ; ; ;
Award ID(s):
1908338
Publication Date:
NSF-PAR ID:
10366803
Journal Name:
The Astrophysical Journal Letters
Volume:
928
Issue:
1
Page Range or eLocation-ID:
Article No. L10
ISSN:
2041-8205
Publisher:
DOI PREFIX: 10.3847
Sponsoring Org:
National Science Foundation
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