Defrere, D.Leger, A.Absil, O.Garcia Munoz, A.Grenfell, J. L.Godolt, M.Loicq, J.Kammerer, JensQuanz, S.Rauer, H.Schifano, L.Creech-Eakman, M.Tuthill, P.Merand, A.2020-07-242020-07-24June 11-15D. Defrère, A. Léger, O. Absil, A. Garcia Munoz, J. L. Grenfell, M. Godolt, J. Loicq, J. Kammerer, S. Quanz, H. Rauer, L. Schifano, F. Tian, "Characterizing the atmosphere of Proxima b with a space-based mid-infrared nulling interferometer," Proc. SPIE 10701, Optical and Infrared Interferometry and Imaging VI, 107011H (24 July 2018); doi: 10.1117/12.2312839978-151061955-50277-786Xhttp://hdl.handle.net/1885/206571Proxima b is our nearest potentially rocky exoplanet and represents a formidable opportunity for exoplanet science and possibly astrobiology. With an angular separation of only 35 mas (or 0.05 AU) from its host star, Proxima b is however hardly observable with current imaging telescopes and future space-based coronagraphs. One way to separate the photons of the planet from those of its host star is to use an interferometer that can easily resolve such spatial scales. In addition, its proximity to Earth and its favorable contrast ratio compared with its host M dwarf (approximately 10-5 at 10 microns) makes it an ideal target for a space-based nulling interferometer with relatively small apertures. In this paper, we present the motivation for observing this planet in the mid-infrared (5-20 microns) and the corresponding technological challenges. Then, we describe the concept of a space-based infrared interferometer with relatively small (<1m in diameter) apertures that can measure key details of Proxima b, such as its size, temperature, climate structure, as well as the presence of important atmospheric molecules such as H2O, CO2, O3, and CH4. Finally, we illustrate the concept by showing realistic observations using synthetic spectra of Proxima b computed with coupled climate chemistry models.DD and OA thank the Belgian national funds for scientific research (FNRS). This work was partly funded by the European Research Council under the European Union’s Seventh Framework Program (ERC Grant Agreement n. 337569) and by the French Community of Belgium through an ARC grant for Concerted Research Action.application/pdfen-AU© 2018 SPIEExoplanetHabitableProxima CenProxima bNullingInfrared imaging2018-07-2410.1117/12.23128392020-04-19