Letters of Intent for 2014

LoI 2014-137
New Windows on Massive Stars, Asteroseismology, Interferometry and Spectropolarimetry

Date: 23 June 2014 to 27 June 2014
Location: Geneva, Switzerland
Contact: Georges Meynet (georges.meynet@unige.ch)
Coordinating division: Division IV Stars
Co-Chairs of SOC: Georges Meynet (Geneva University)
Philippe Stee (Observatoire de la Côte d'Azur)
Chair of LOC: Georges Meynet (Geneva University)



-massive stars
-magnetic fields
-stellar winds
-circumstellar environments
-surface abundances
-Be stars, supergiants, luminous blue variables, Wolf-Rayet stars



Massive stars are very important driving agents of the evolution of the galaxies and thus represent key objects to go from stellar physics to the physics of galaxies.

As the progenitors of core collapse supernovae, of the long soft Gamma Ray Bursts, of neutron stars and black holes, they are connected with the most intriguing objects in the Universe.

Nowadays, asteroseismology, interferometry and
spectropolarimetry allow to see what could have been thought once as unreachable characteristics of stars in general and of massive stars in particular:

Asteroseismology allows to probe what happens in the interior of stars, to identify the zones where steep gradients of chemical composition and of angular velocity occur. This provides essential clues on transport processes inside stars. These transport processes, together with the change of composition due to nuclear reactions and mass loss by stellar winds and/or through mass transfer in close binaries drive the evolution of stars.

Interferometry explores the shape of stars, the structure and the kinematics of their circumstellar environments. This allows to probe the deformation of stars resulting from fast rotation and/or tidal forces, to probe the physics of disk formation around early-type stars, to obtain diagnostic of possible anisotropies in the stellar winds.

Spectropolarimetry gives information on the amplitudes and topologies of surface magnetic fields. Magnetic fields represent one of the great issues in massive star physics. The magnetic field impacts the way angular momentum is distributed in the interior of stars and it may also couple the wind with the surface of the star. These two characteristics probably play a key role in the angular momentum content of the core at the time of the core collapse event and have an important impact on the way stars explode and on the physical properties of the stellar remnant.

All these three technics already have obtained fascinating results on massive stars and time is ripe for organising an international conference focusing on the achievements reached so far by these three technics.

The main aims of the conference will be to
1) allow astronomers interested in massive stars to understand the basics of these three technics, to understand their potentialities as well as their present limitations and future developments,
2) explore the benefits of these technics used together and also with more classical approaches as photometry and spectroscopy to address topical questions in massive star evolution,
3) allow observers to learn about the most recent challenges in massive star modeling.