The computation of the outermost layers of a star (the atmosphere) requires to solve in details the radiative transfer equation, whereas an analytical formula provides the radiative flux in optically thick layers, which is the case for the inner structure. Then, to have a complete stellar model from the center up to the optically thin layers, one should compute the inner structure on one hand and the uppermost part on the other, and connect the two in some way.

After a non-exhaustive review of what is done with other evolutionary codes, we will describe how we deal with the problems met while performing the junction of an inner structure computed with the Toulouse-Geneva Evolution Code (TGEC) and an ATLAS9 atmosphere. Global behaviour of some physical quantities when considering the complete model will be shown, along with the effect on the oscillation frequencies.

Theoretical atmosphere models provide the basis for a variety of applications in astronomy. In simplified one-dimensional (1D) atmosphere models, convection is usually treated with the mixing length theory despite its well-known insufficiency, therefore, the superadiabatic regime is poorly rendered. Due to the increasing computational power over the last decades, we are now capable to compute large grids of realistic three-dimensional (3D) hydrodynamical model atmospheres with the realistic treatment of the radiative transfer. We have computed the Stagger-grid, a comprehensive grid of 3D atmosphere models for late-type stars. In the presented contribution, we discuss initial results of the grid by exploring global properties and mean stratifications of the 3D models. Furthermore, we also depict the differences to classic 1D atmosphere models.

We discuss four questions dealing with massive star evolution. The first one is about the origin of slowly rotating, non-evolved, nitrogen rich stars. We propose that these stars may originate from initially fast rotating stars whose surface has been braked down. The second question is about the evolutionary status of α-Cygni variables. According to their pulsation properties, these stars should be post red supergiant stars. However, some stars at least present surface abundances indicating that they should be pre red supergiant stars. How to reconcile these two contradictory requirements? The third one concerns the various supernova types which are the end point of the evolution of stars with initial masses between 18 and 30M⊙, i.e. the most massive stars which go through a red supergiant phase during their lifetime. Do they produce types IIP, IIL, IIn, IIb or Ib supernovae or do they end without producing any SN event? Finally, we shall discuss reasons why so few progenitors of type Ibc supernovae have yet been detected?

Two-dimensional models of rapidly rotating stars are already unavoidable for the interpretation of interferometric or asteroseismic data of this kind of stars. When combined with time evolution, they will allow the including of a more accurate physics for the computation of element transport and the determination of surface abundances. In addition, modeling the evolution of rotation will improve gyrochronology. Presently, two-dimensional ESTER models predict the structure and the large-scale flows (differential rotation and meridional circulation) of stars with mass larger than 1.7 M⊙ at any rotation rate. Main sequence evolution can be mimicked by varying the hydrogen content of the convective core. Models have been successfully tested on half a dozen of nearby fast rotating stars observed with optical or infra-red interferometers. They are now the right tool to investigate the oscillation spectrum of early-type fast rotators.

The Asymptotic Giant Branch phase of low and intermediate mass stars (1.2 < M/M⊙ < 6.0) synthesizes nearly half of the heavy elements (A > 56) in the Universe. This evolutionary phase represents an ideal laboratory to test our knowledge of stellar microphysics and macrophysics. In fact, the nucleosynthesis occurring in AGB stars sensibly depends on the adopted physical inputs and on the assumptions in the treatment of physical phenomena like convection, mass loss and rotation. In this contribution we illustrate the characteristics of low mass (1.5 < M/M⊙ < 3.0) AGB models at different metallicities (− 2.2 < [Fe/H] < 0.2). In particular, we highlight the effects induced by the use of proper C-enhanced low temperature opacities and the importance of the treatment of the envelope radiative/convective interface on the formation of the 13C-pocket (the main neutron source). We briefly describe main characteristics of the FRUITY database on AGB stars nucleosynthesis, created by directly coupling a full nuclear network with evolutionary models. Finally, we discuss the effects that the inclusion of rotation has on the s-process pattern in low-mass AGB stars.

Traces of heavy metal in cool DZ white dwarfs may be attributed to the accretion of circumstellar dust. This dust is thought to originate from the tidal disruption of some rocky material, they provide a unique opportunity to study the composition of extra-solar planetary systems. The determinations of precise atmospheric parameters and abundances require accurate description of the line profiles of the identified features. We present absorption spectra of Na-He and Ca+-He for the conditions prevailing in cool white dwarfs.

Our aim is to perform Non-LTE iron abundance calculations on a sample of Kepler red giants with reliable fundamental atmospheric parameters from asteroseismology, specifically log g, in order to calibrate for unknown atomic collisional effects with neutral hydrogen for which quantum mechanical data does not yet exist. Preliminary results show better mutual agreement between FeI and FeII lines as compared to LTE, as well as less FeI abundance dispersion than that of previous work.

A large database of HgMn stars is compiled, which contains the results of new measurements of their spectroscopic parameters combined with the data available in the literature. This database gives us an idea about the evolutionary changes of the HgMn stars.