Christophe Martayan is involved in both the CU6 (Spectroscopic Processing) and CU8 (Astrophysical Parameters) units in DPAC. In CU6 he manages the software module for "coarse characterization of sources". This module is the first of the "single transit analysis" package and must provide some information (such as the presence of emission lines, or detected lines, the gradient of the RVS spectra, the S/N ratios, etc.) for the other work packages, as well as for the final Gaia catalogue,
Christophe is very interested in Emission Line Stars (ELS) since this subject concerns all of the Hertzsprung-Russel diagram - the ELS range from massive to light stars (Oe, Be to Flare stars) and from unevolved to evolved stars (WR, PN, Mira to TTauri, Herbig Ae/Be). For these stars one tries to provide information such as lists of identified lines, EW, FWHM of lines, and also when possible, parameters of the circumstellar material and of the central star. However, the physics at the origin of the emission and at the origin of the circumstellar material of these objects are very different and not yet well understood. In CU8, Christophe manages the "Emission Line Stars" and "models for emission line sources" scientific modules. He also contributes to the "Hot Stars" module and is a member of the Gaia HOt Stars Team (GHOST).
Christophe's other scientific interests are the massive stars in the local group of galaxies. For example, he studies the effects of the metallicity, star-formation conditions, evolution, etc, in the B and Be star populations in the Magellanic clouds, in the Milky Way, and, in future, in other galaxies.