Alain Doressoundiram

@alplaneto.bsky.social

94 Followers 35 Following

Astrophysicien à l'Observatoire de Paris - Université PSL, Co-PI de SIMBIO-SYS (BepiColombo), Co-I de MIRS (MMX). Responsable du Master de Planétologie à l'Observatoire de Paris. Directeur Adjoint du LIRA. Porteur du projet ERASMUS+ Exo4Edu.

An international team of astronomers using the NASA/ESA Hubble Space Telescope have made new measurements of Uranus' interior rotation rate with a novel technique, achieving a level of accuracy 1000 times greater than previous estimates. By analysing more than a decade of Hubble observations of Uranus' aurorae, researchers have refined the planet’s rotation period and established a crucial new reference point for future planetary research. Determining a planet’s interior rotation rate is challenging, particularly for a world like Uranus, where direct measurements are not possible. A team led by Laurent Lamy (of LIRA, Observatoire de Paris-PSL and LAM, Aix-Marseille Univ., France), developed an innovative method to track the rotational motion of Uranus’ aurorae: spectacular light displays generated in the upper atmosphere by the influx of energetic particles near the planet’s magnetic poles. This technique revealed that Uranus completes a full rotation in 17 hours, 14 minutes, and 52 seconds — 28 seconds longer than the estimate obtained by NASA’s Voyager 2 during its 1986 flyby.
Animation of 2024 YR4’s Earth impact probability over time (credit: NASA/JPL Center for Near-Earth Object Studies)
https://lira.obspm.fr/-Spectro-imageur-MIRS-pour-la-mission-MMX-de-la-JAXA- Cette mission inédite, développée par la JAXA, sera la première au monde à réaliser un aller-retour vers le système martien ! Son objectif ? Étudier les satellites de Mars et rapporter des échantillons de Phobos pour percer les mystères de l’histoire martienne.
Ecliptic projection of the asteroid orbit (in red). Credit: ESA / PDO
https://www.esa.int/Science_Exploration/Space_Science/BepiColombo/Top_three_images_from_BepiColombo_s_sixth_Mercury_flyby
Le LIRA (Laboratoire d’instrumentation et de recherche en astrophysique)