Stellar Astrophysics

Stellar Astrophysics

Manager: Yohann Scribano

 

Introduction

The AS team group members work on various aspects of stellar physics. They combine observations with large telescopes (VLT(I), CFHT, IRAM, HST, TBL) with modelling and numerical simulations, on local, national (GENCI), and international (Canada) facilities.

Studies are undertaken on various types of stars. They focus on their evolution, their surface properties (including magnetism) and their close environment where astrochemical studies link stars to the
interstellar medium.

Some members of this team are strongly involved in working groups of the ESA/PLATO mission, while others are involved in the SPIRou legacy survey and the preparation of SPIP.

 

Research topics

The AS team performs studies on various fields of stellar physics, with special emphasis on the following three structuring topics:

  • surface properties and stellar evolution:

Evolutionary models are developped among the team. They include non-standard mixing processes (rotation, atomic diffusion, thermohaline convection) and cover the entire mass range (from low-mass to high-mass stars). The models are confronted to observations and stellar parameters determined by means of quantitative spectroscopy performed with atmosphere models.

  • magnetism:

Observations of magnetic stars are conducted with the most powerful spectropolarimeters (ESPaDOnS, Neo-NARVAL, SPIRou). The goal is to detect and characterize the topology and time variation of surface magnetic field, in order to understand their nature, origin and evolution. The impact on exoplanets is also investigated. All types of stars are targeted, with special emphasis on red dwarfs and cool evolved stars (AGB and red (super)giants).

  • astrochemistry:

Numerical simulations are conducted to understand the formation of molecular species in both circumstellar and interstellar environments. The formation of dust in envelopes of cool stars is particularly studied. Numerical methods are also developped to study chemical reactions, especially in the early Universe.

 

Observations Services

Team members are involved in the following observing duties of CNRS/INSU:

 

Team Members
  • Permanent staff
    • Gérard JASNIEWICZ (Astronomer)
    • Éric JOSSELIN (Associate professor)
    • Agnès LÈBRE (Astronomer)
    • Fabrice MARTINS (CNRS research associate) – team leader
    • Julien MORIN (Associate professor)
    • Ana PALACIOS (Astronomer)
    • Bertrand PLEZ (Professor)
    • Olivier RICHARD (Associate professor)
    • Yohann SCRIBANO (Associate professor)
    • Dahbia TALBI (CNRS research director)
    • Hervé Wozniak (Astronomer)
    • Nicolas MAURON (Scientific collaborator)
    • Henri REBOUL (Emeritus)
  • PhD students and post-docs
    • Thibaut DUMONT (PhD student – co-direction with Geneva Observatory)
    • Lucien Dupuy (PhD student)
    • Stefan GEORGIEV (PhD student – co-direction with Sofia University)
    • Svetla Tsvetkova (Post-doc)
  • Former members of the team
    • Louis AMARD (PhD student 2012-2016, dir. Ana Palacios)
    • Duncan BOSSION (PhD student 2016-2019, dir. Y. Scribano)
    • Morgan DEAL (PhD student 2013-2016, dir. Olivier Richard)
    • Dimitri DOUCHIN (PhD student 2011-2014, dir. Gérard Jasniewicz)
    • Rana EZZEDDINE (PhD student 2012-2015, dir. Bertrand Plez)
    • Nicolas FABAS (PhD student 2008-2011, dir. Agnès Lèbre)
    • Pierre GHESQUIÈRE (PhD student 2011-2015, dir. Dahbia Talbi)
    • Anthony HERVÉ (Post-Doc 2013-2014, contact Fabrice Martins)
    • Johanna ITAM-PASQUET (PhD student 2013-2016, dir. G. Jasniewicz & D. Puy)
    • Julien LAMBERT (PhD student 2009-2012, dir. Éric Josselin)
    • Benjamin TESSORE (PhD student 2014-2017, dir Agnès Lèbre & Julien Morin)
Team publications