CRAL

CRAL@ENS Seminar - Adnan Ali Ahmad (AstroENS)
2025-11-21 11:00 - 12:00 (Europe/Paris) | ENS

CRAL@Obs Seminar - Mathias Nowak (LIRA, Paris)
2025-12-05 11:00 - 12:00 | Observatoire
Title:
Results and perspectives from the ExoGRAVITY Large Programme

Abstract:
The direct detection of a giant exoplanet using long-baseline interferometry in 2019 marked the debut of the GRAVITY instrument in exoplanet research. This breakthrough was followed by the detailed spectroscopic characterization of beta Pictoris b’s atmosphere in 2020, demonstrating the potential of long-baseline interferometry for studying young giant planets. These successes led to the establishment of the ExoGRAVITY Large Programme on the Very Large Telescope Interferometer (VLTI), dedicated to the characterization of young giant planets. Fast forward five years, and this innovative method has yielded a wealth of discoveries, including the direct confirmation of beta Pictoris c, the detection of brown dwarf companions inferred from Gaia data, and the resolution of the « underluminous » brown dwarfs puzzle. The implementation of GRA4MAT has expanded observation capabilities to include longer wavelengths (L to N bands), while the GRAVITY+ upgrade promises enhanced contrast at small separations in K-band. Initiatives are now underway to explore shorter wavelengths (J and Y bands) at the VLTI, offering strong potential for exoplanet studies. The detection of giant planets in reflected light, rather than thermal emission, is quickly becoming the next frontier in high-contrast interferometry, inspiring more ambitious ideas, such as adding a new Unit Telescope (UT) to the VLTI array. In this talk, I will review the key results of the ExoGRAVITY Large Programme and provide perspectives on upcoming developments in high-contrast interferometry for exoplanet characterization.

CRAL@Obs Seminar - Faustine Cantalloube & Julien Milli (IPAG, Grenoble)
2025-12-12 11:00 - 13:00 | Observatoire
Titre: L’impact du dérèglement climatique sur l’astronomie observationnelle

Résumé: Les grands observatoires astronomiques fonctionnant dans le visible/infrarouge sont souvent accompagnés de station météo afin de suivre les paramètres clés qui affectent la qualité des observations obtenues. La plupart de ces suivis ont maintenant atteint une échelle temporelle de 30ans, permettant d’explorer si il existe des variations climatiques dans les données. L’étude à donc été menée sur de nombreux sites, en particulier à l’observatoire du Cerro Paranal (Chili) qui abrite le Very Large Telescope et l’observatoire du Mauna Kea (Hawaii) qui abrite notamment le Canada France Hawai Telescope. Cependant, un observatoire astronomique est plus qu’un ensemble de quantités physiques, il faut aussi prendre en compte tout un ecosystème qui permet à un observatoire d’opérer de façon fonctionnelle…
