Exoplanets and brown dwarfs detections through gravitational microlensing. Study of interferometric observations. - INSU - Institut national des sciences de l'Univers Access content directly
Other Publications Ph.D. Thesis Year : 2015

Exoplanets and brown dwarfs detections through gravitational microlensing. Study of interferometric observations.

Clément Ranc
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Abstract

Gravitational microlensing effect has become a unique tool to detect and characterise exoplanets. A microlensing effect occurs when a foreground star (the microlens) and a background star (the source) are aligned with the Earth on the same line of sight. The light from the furthest star, usually in the Galactic bulge, is deflected by the microlens located on the disk. During this phenomenon, multiple images of the source are created by the lens, bigger than the source that consequently seems amplified. When one of these images are located in the vicinity of an exoplanet, a short amplification jump occurs revealing its presence. After a quick overview of the exoplanets field of research, I highlight the specificities of microlensing comparing to the other planets detection techniques. Then, I describe in details the modelling of microlensing effects, from a theoretical to a numerical point of view. In a third part, I describe the detection of the first brown dwarf orbiting a solar-type star using microlensing, strengthening the recent idea that microlensing will lead to a better understanding of the mechanisms involved in the brown dwarfs formation, still not fully understood. Finally, I investigate the potential of interferometric observations of microlensing events that will give, in the future, new original constraints on the microlens physical properties. First, we introduce a new formalism that closely combines interferometric and microlensing observable quantities. Secondly, we determine an average number of events that are at reach of long baseline interferometers every year.
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insu-03644731 , version 1 (19-04-2022)

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Clément Ranc. Exoplanets and brown dwarfs detections through gravitational microlensing. Study of interferometric observations.. 2015. ⟨insu-03644731⟩
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