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The sun and asteroseismology

  • Illustration asteroseismology.

Developing and testing solar and stellar models

This group works towards developing and testing the most accurate solar and stellar models to address several scientific issues. Models are tested several different constraints from helioseismology to eclipsing binaries to asteroseismology, also complemented with parallaxes from Gaia.

The Sun, the best laboratory for stellar physics

The Sun is the best laboratory for stellar physics. The properties of the solar interior are known with great detail. This is possible because the Sun oscillates in hundreds of thousands of acoustic modes (p-modes) and the frequencies are measured to very high precision (typically, one part in 105) both from space-born missions and Earth-based solar observatories. The study of these oscillations, helioseismology, allows inferring the inner structure of the Sun -i.e. the run of density, temperature, pressure and even rotation with radius- very accurately and precisely.

Due to this wealth of data our understanding of stellar structure and evolution can be subject to stringent tests when trying to reproduce solar properties. The Sun is a fundamental benchmark against which modelling of physical processes in stars is tested.
 
The advent of space-borne asteroseismology, initially with the Corot and Kepler missions, now with K2 and TESS and PLATO in the near and mid-term, has opened up a new window to studies of stellar interiors. With its rapid development, asteroseismology has become, in less than a decade, a fundamental tool not only in studies of stellar physics, but also in the study of exoplanet hosting stars and systems, and galactic archaeology.

Satellite image of the sun. Credit: SOHO.

Focus

The fundamental and unifying line of work is the theoretical studies of the solar and stellar interiors by means of state-of-the-art structure and evolution models.

Our ultimate goal is to develop and test the most accurate solar and stellar models, and then use these models to address several scientific issues. The development of models is carried out along several paths: improvement of the microphysics used in the models (nuclear reaction rates, opacities, equation of state), better modelling of physical processes (e.g. near-surface convection based on 3D hydrodynamic models) and numerical techniques. Models are tested on several different constraints from helioseismology to eclipsing binaries to asteroseismology, also complemented with parallaxes from Gaia.

Some of the scientific problems we are interested in addressing are: the solar abundance problem, solar models for particle physics including work on solar neutrinos, and constraints on exotic properties of matter (e.g. magnetic neutrino dipole) and/or properties of exotic matter (e.g. dark matter candidates). Also, we are interested in any application of stellar models to astrophysical problems. Based on spectroscopic, photometric, asteroseismic and astrometric data (any combination thereof) we work on the characterisation of stellar properties that enable studies from individual objects (such as planet hosting stars) or large-scale populations. For attacking some of these topics, we have also developed BeSPP (Bellaterra Stellar Parameters Pipeline), a state-of-the-art statistical analysis tool based on Bayesian statistics that allow inference of stellar parameters based on different classes of input data and a large library of stellar models containing about 100 million models.

We are part of the Gaia-ESO survey, the Kepler and K2 mission, and are external collaborators in APOGEE, the SDSS-IV experiment for galactic archaeology. We are also members of the Steering Committee of the working group of solar like oscillators of the oncoming NASA mission TESS.

Senior institute members involved

Meet the senior researcher who participates in this research line.

  • Aldo Serenelli

    More theory and observations