Stars Formation & Evolution


The study of the formation and evolution of stars is a key research field for all major questions in astrophysics and cosmology, from the study of the planets in the Universe as a whole, through the evolution of our Sun and galaxies. The UNIGE groups are studying the formation of stars, the structure and evolution of massive stars, the structure and evolution of stars of small and intermediate masses, and variability of objects in the Universe. The stellar evolution models calculated in Geneva include the most sophisticated and most detailed physics in the world. These models are among the most used by the astronomical community. The following research topics are developed by the different research groups involved:

Star and planets formation.

The mechanisms of formation of stars and indirectly planets, are studied using observations at different wavelengths of proto-planetary disks and jets of matter around stars in formation.

Progenitors of white dwarfs, neutron stars and black holes.

Evolutionary scenarios leading to these stellar residues are studied, in particular the influence of metallicity and the initial rotation of a star on its final stage.

Physics of transport mechanisms in the stars.

The effects of rotation, internal waves, magnetic field, atomic diffusion and thermohaline convection inside stars are modeled. These mechanisms affect strongly the evolution of stars and systematically promote the match between theory and observations. It is expected to participate in many campaigns of observations in order to obtain new constraints on theoretical models, in particular measures of abundance and magnetic field at the surface of stars of various types.

Asteroseismology.

The UNIGE groups are involved in the analysis of data from the satellite COROT and the KEPLER space mission. The aim is to extract from the observed vibrations frequencies of the stellar surfaces unparalleled insight of the internal structure. It is imperative to develop expertise in this leading-edge field that opens a new window on stellar interiors.

Chemical, photometric and dynamics evolution of star clusters and galaxies.

An important part of the UNIGE research is dedicated to stellar nucleosynthesis, both the light elements which have a cosmological significance and the heavy elements that allow to trace the history of star formation in the Universe. The nucleosynthesis constraints are coupled with those from the dynamics to acquire a complete and consistent view of the formation and evolution of star clusters, bursts of star formation and galaxies.

The first generations of stars in the Universe.

The study of the evolution of stars formed from primordial matter allow to deduce the implications for reionization and the early stages of chemical and photometric evolution of galaxies observed at high redshift.

Stars as physics laboratory.

The UNIGE computing models allow to study the consequences on the evolution of the first generation of stars and the Sun of the WIMPS annihiliation (Weakly Interactive Massive Particles, candidates for dark matter ) and changes in physical constants. These stellar models take into account the physical processes observed in the Earth's atmosphere and oceans, which puts more than ever before the interdisciplinary nature of stellar physics .

GAIA satellite.

The study of the variability of astronomical objects, stars, galaxies, asteroids, is a major theme of the scientific program of the GAIA satellite of the European Space Agency (ESA), launched on 19 December 2013. During 5 years  1 billion objects  will be measured in astrometry, photometry and spectroscopy. It will result in particular progress in stellar and galactic physics and a 3D map of the Galaxy.


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