Le vendredi 2 octobre 2026, Said HMIDDOUCH présentera l'examen en vue de l’obtention du grade académique de Docteur en Sciences (Collège de doctorat en Sciences spatiales) sous la direction d'Emmanuel JEHIN et Abdelhadi JABIRI (cotutelle avec l’Université Cadi Ayyad).

Cette épreuve consistera en la défense publique d’une dissertation intitulée :

« Monitoring the Activity and Composition of Long Period Comets with TRAPPIST Telescopes ».

Le Jury sera composé de :

M. D. GRODENT (Président), Mme et MM. Z. BENKHALDOUN (University of Sharjah), A. DAASSOU (Université Cadi Ayyad), J. DE KEYSER (Royal Belgian Institute for Space Aeronomy), D. HUTSEMEKERS (Secrétaire), A. JABIRI (Université Cadi Ayyad) (Promoteur), E. JEHIN (Promoteur), C. OPITOM (University of Edinburgh).

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Abstract

Comets are among the most pristine remnants of the early Solar System, preserving information about its formation and evolution. Their volatile compounds and organic molecules also make them potential contributors to the delivery of water and prebiotic material to the early Earth. However, understanding their diversity requires consistent, long-term observations, as measurements obtained over only a few nights may provide an incomplete picture of their activity and composition.

This thesis investigates cometary activity, composition, and evolution of a sample of long period comets coming from the Oort Cloud through extensive monitoring with the TRAPPIST telescopes, complemented by high-resolution spectroscopy obtained at the ESO Very Large Telescope. Narrow-band and broad-band photometry provide homogeneous measurements of gas production, molecular abundance ratios, dust activity, and optical colors of the dust along the comet orbit. These observations allow us to examine how the cometary properties vary with the heliocentric distance and their dynamical origin.

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