New theoretical model accounts for sun's rotation and magnetic field

The values of the chemical abundances at the surface of the sun were revised by a new set of data in the early 2000s. The new abundances made it through several new analyses. It was up to the solar models to adapt since they serve as a reference for the study of stars in general. A team of astronomy from the University of Geneva, Switzerland, in collaboration with the Universit de Lige, has developed a new theoretical model that helps solve part of the problem: considering the sun's rotation. Nature Astronomy published the results of this study.

The sun is a fundamental test for our understanding of stellar physics. Patrick Eggenberger is a researcher at the Department of astronomy of the UNIGE and the first author of the study.

The results predicted by the theoretical models should be in line with the observations. The sun burns its hydrogen in the core. How is the energy transported to the surface? Chemical elements drift within the sun due to rotation and magnetic fields.

The solar model is standard.

The standard solar model we used until now considers our star in a very simplified manner, with regard to the transport of the chemical elements in the deepest layers, and on the other hand, for the rotation and the internal magnetic fields that were completely neglected until now.

The solar abundances were revised in the early 2000s thanks to an improved analysis. The ripples in the waters of the solar modeling were caused by the new abundances. No model was able to reproduce the data obtained by helioseismology, in particular the abundance of helium in the solar envelope.

The key role of rotation and magnetic fields is a new model.

The evolution of rotation is included in the new solar model, as is the magnetic instabilities it creates. It is important for the sun as for stellar physics in general and has a direct impact on the chemical evolution of the Universe, given that the chemical elements that are crucial for life on Earth are cooked in the core of the stars.

The new model accurately predicts the concentration of helium in the outer layers of the sun, as well as reflecting that of lithium which had resisted modeling.

The problem is not solved.

The new model doesn't solve every challenge raised by helioseismology. The theoretical models of the sun predict a depth offset of 10,000 km, according to the researcher who co-authored the paper. Thanks to the new model, we can learn more about the physical processes that can help us resolve the problem.

There is an update of solar-like stars.

We are going to have to revise the mass, age and radii of the stars that we have studied so far. In most cases, solar physics is used in case studies close to the sun. If the models for analyzing the sun are changed, this update must also be done for other stars like ours.

This observatory of 24 telescopes should fly to the Lagrange point 2, opposite of Earth, if we want to better characterize the host stars of planets.

More information: P. Eggenberger et al, The internal rotation of the Sun and its link to the solar Li and He surface abundances, Nature Astronomy (2022). DOI: 10.1038/s41550-022-01677-0 Journal information: Nature Astronomy Citation: New theoretical model accounts for sun's rotation and magnetic field (2022, May 31) retrieved 31 May 2022 from https://phys.org/news/2022-05-theoretical-accounts-sun-rotation-magnetic.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.