Séminaires du
Département d'Astrophysique, Géophysique et Océanographie

Jeudi 19 octobre, 15h45

Salle de réunion AGO (local -1/14)
Institut d'Astrophysique et de Géophysique
Quartier Agora, Allée du 6 Août, 19C, B-4000 Liège 1 (Sart-Tilman)

Study of comets using TRAPPIST telescope network.

Franscisco Pozuelos Romero
(STAR Institute)

Comets are remnants of the early stages of the Solar system and, likely, the most pristine solar system bodies. Understanding their nature and their evolution is a must to understand the history of our Solar System. Comets contain complex organic molecules, and may have played a key role in the transfer of water and organics from the interstellar medium to the early Earth, contributing to the origin of life. This interest is well illustrated by the fact that several space missions have targeted small bodies of the solar system, and particularly comets like the very successful ESA Rosetta/Philae mission currently returning impressive science data that are going to revolutionize our knowledge of comets. The nucleus of a comet, typically a few kilometers in diameter, is essentially composed of water ice mixed with carbon oxides, methane, ammonia, and dust particles. When the comet approaches the Sun, the ices sublimate, forming a gaseous and dusty coma. Solar radiation and wind blow this material to form spectacular cometary tails. Investigations of the chemical composition of comets are important for a variety of reasons. In addition to revealing the characteristics of comets themselves, the composition of comets holds unique clues to conditions in the early solar nebula and the Solar Systemís formation processes, since comets remain the most pristine objects available for detailed studies. In particular, knowledge of the bulk chemical composition of comets and how the composition varies among individuals and/or with exposition to solar radiation can provide strong constraints on the composition and temperature of the proto-planetary nebula at the time solid bodies began to form some 4.6 billion years ago. Depending on the region of formation in the protosolar nebula, comets are currently stored in three main reservoirs: the Oort cloud, the Kuiper belt and the main asteroid belt. By studying comets from different reservoirs we can probe the different environments in which they formed, and also better understand their role in the Solar system as suppliers of water and organics.

Café, thé et biscuits seront servis après le séminaire...