Variability of the Sun's Luminosity Places Constraints on the Thermal Equilibrium of the Convection Zone

L. E. A. Vieira , G. Kopp , Thierry Dudok de Wit (1) , L. A. da Silva , F. Carlesso , A. R. Barbosa , A. Muralikrishna , R. Santos

1 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace

Luminosity, which is the total amount of radiant energy emitted by an object, is one of the most critical quantities in astrophysics for characterizing stars. Equally important is the temporal evolution of a star's luminosity because of its intimate connection with the stellar energy budget, large-scale convective motion, and heat storage in the stellar interior. The Sun's luminosity and its variation have not been measured to date because current observations of the solar radiative output have been restricted to vantage points near the Earth. Here, we model the solar luminosity by extending a semiempirical total solar irradiance (TSI) model that uses solar-surface magnetism to reconstruct solar irradiance over the entire 4π solid angle around the Sun. This model was constrained by comparing its output to the irradiance in the Earth's direction with the measured TSI. Comparing the solar luminosity to the TSI on timescales from days to solar cycles for cycles 23 and 24, we find poor agreement on short timescales (

Keywords: Solar spectral irradiance; Solar magnetic flux emergence; Stellar luminosities; Solar cycle; Solar dynamo; Stellar convective zones; Solar convective zone

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]

L. E. A. Vieira, G. Kopp, Thierry Dudok de Wit, L. A. da Silva, F. Carlesso, et al.. Variability of the Sun's Luminosity Places Constraints on the Thermal Equilibrium of the Convection Zone. The Astrophysical Journal Supplement Series, 2022, 260, ⟨10.3847/1538-4365/ac626d⟩. ⟨insu-03708680⟩