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Projects of the Spectre Team
Comets, planets and asteroids form within a "proto-planetary" disk of gas and dust surrounding one (or more young) stars. This "nebula" results from the gravitational collapse of a molecular cloud within the interstellar medium. These disks eventually evolve into a planetary system, i.e. a star surrounded by its cortege of planets, like the present-day Solar System. Cosmochemical diagnostics such as isotope ratios are now observable for a variety of disks, and may be spatially resolved using the ALMA radio interferometer. These observations can be compared with our very detailed knowledge of the Solar System, for example by comparing the chemical composition of disks with that of comets. Major advances have recently been made in the study of comets, thanks to the Rosetta, New Horizons and Hayabusa 2 space missions.
In the SPECTRE team, our efforts focus on the observation of "probe" molecules in pre-stellar cores (precursors of disks) and proto-planetary disks, and on the analysis of ROSETTA, NEW HORIZONS and HAYABUSA 2 spectra. The aim is to assess the contribution of interstellar heritage to the chemical composition of disks and comets. This work benefits from the team’s theoretical and experimental expertise, via fundamental data (laboratory infrared spectra, collision cross sections, etc.) and numerical models (radiative transfer and chemical kinetics).
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Star-planet relationships are key parameters for understanding the evolution of planetary space environments. These relationships are driven by two main sources. The first is stellar electromagnetic flux. In the SPECTRE team, we focus on the energetic part (UV/UEV/XUV) responsible for excitations and ionizations in the upper atmospheres (thermosphere and ionosphere). The second source is the stellar wind, composed mainly of protons and electrons. Its effects depend on the presence of a planetary magnetic field. In the SPECTRE team, we have developed a kinetic code to evaluate the relative impacts of these two sources. For example, we have studied the history of the Martian space environment as a function of solar activity.
In the SPECTRE team, our recent efforts have focused on exploring the Earth’s space environment from the ground (radar and optical experiments) and from space (nanosatellites), using instruments developed by our team to study the polar aurora and night-time radiation.
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