Studying the variability of the He triplet to understand the detection limits of evaporating exoplanet atmospheres

Article Article scientifique Article Studying the variability of the He triplet to understand the detection limits of evaporating exoplanet atmospheres eng 2025-07-29 2025-08 author Mercier Samson Jules 0000-0002-0962-7585 989852 author Dumusque Xavier 0000-0002-9332-2011 583253 Département d'astronomie (ASTRO) author Bourrier Vincent 0000-0002-9148-034X 828250 Département d'astronomie (ASTRO) author Al Moulla Khaled Sleiman 0000-0002-3212-5778 945221 Khaled Al Moulla author Cretignier Michaël 0000-0002-2207-0750 805600 author Dethier William 0009-0007-3622-0928 author Lo Curto Gaspare 0000-0002-1158-9354 665040 author Figueira Pedro Ricardo 0000-0001-8504-283X 637397 Département d'astronomie (ASTRO) author Lovis Christophe 0000-0001-7120-5837 134919 Département d'astronomie (ASTRO) author Pepe Francesco Alfonso 0000-0002-9815-773X 124203 Département d'astronomie (ASTRO) author Santos Nuno C. 0000-0003-4422-2919 author Udry Stéphane 0000-0001-7576-6236 23409 Département d'astronomie (ASTRO) author Wildi François 0000-0002-9216-4402 24311 Département d'astronomie (ASTRO) author Allart Romain 0000-0002-1199-9759 751868 author Baron Frédérique 0000-0002-5074-1128 author Bouchy François 0000-0002-7613-393X 133687 Département d'astronomie (ASTRO) author Carmona Andres 0000-0003-2471-1299 author Cointepas Marion 0009-0001-6168-2178 934336 Département d'astronomie (ASTRO) author Doyon René 0000-0001-5485-4675 author Frensch Yolanda Gerardina Cécile 0000-0003-4009-0330 975671 Département d'astronomie (ASTRO) author Grieves Nolan 0000-0001-8105-0373 930970 author Mignon Lucile 984034 author Nielsen Louise Dyregaard 0000-0002-5254-2499 868873 A8 10.1051/0004-6361/202452856 0004-6361 https://www.aanda.org/10.1051/0004-6361/202452856 <p>With more than a dozen significant detections, the helium triplet has emerged as a key tracer of evaporating exoplanet atmospheres. This near-infrared feature can be observed from the ground and holds great promise, especially with upcoming observations provided by new-generation instruments such as the Near Infrared Planet Searcher (NIRPS). However, as the helium triplet is also present in stellar spectra, careful removal of the average stellar contribution is necessary to accurately characterize the atmospheres of transiting exoplanets. In this study, we analyze multi-epoch observations of the Sun obtained with NIRPS to investigate the temporal variability of the helium triplet. Our findings reveal significant variability across different timescales, ranging from minutes to days. We identify telluric contamination and stellar activity as likely sources for the short-term and long-term variability, respectively. Importantly, we demonstrate that this variability has minimal impact on the retrieval of planetary parameters crucial to the study of atmospheric escape.</p> Dewey 520 26 Département d'astronomie 12 false 862 Direction de recherche "Planètes extrasolaires" Astronomy & astrophysics 700 775173af-5acf-42b9-8dd7-ba7ea66270e7 Article (Published version) Public Article_scientifique_from_crossref.pdf 42413737 application/pdf CC BY-4.0 0b0c1c16266fdc241e87092fb7907c44525b517d69a4ff5bc3c3c435a1fc9fd8 openAccess Faculté des sciences / Département d'astronomie

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Studying the variability of the He triplet to understand the detection limits of evaporating exoplanet atmospheres	Astronomy & astrophysics			2025	16	106

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Mercier, Samson Jules