LIRA, a pioneer in astrophysics and instrumentation, pushes back the frontiers of knowledge
LIRA
Laboratory for Instrumentation and Research in Astrophysics
Deep-learning maps of fresh crater rays on Mercury
25 May 2026On Mercury, some young impact craters are surrounded by bright, filamentary “rays”: ejecta made of relatively immature material excavated by the primary impact and by secondary impacts. Over time, space weathering (micrometeoroid bombardment and solar-wind irradiation) darkens these deposits and the rays fade, making them a useful indicator of geologically young surfaces (hundreds of Myr). In his PhD work at LIRA, Michele Lissoni developed a deep-learning approach that combines a connection model (is a tile linked to a crater by a ray?) with a segmentation model (where is the ejecta?), trained on the global MDIS Enhanced Color mosaic at 665 m/pixel. The resulting global product overlays ejecta masks from many craters—each in a different color—opening the door to systematic studies of ray geometry, spectral properties, crater ages, and impact dynamics.
Colloquia du LIRA ESCAPE project: investigating observing and image processing methods for exoplanet direct imaging with future space...
Séminaires du pôle Étoiles et Galaxies Massive runaway stars in the Milky Way: new insights from Gaia and multiwavelength studies
Théminaires Planétologie La chimie radiative est l’ange caché et la chimie de l’eau est le démon caché
News
Elsa Huby, winner of the 2026 Charles Defforey Foundation–Institut de France Grand Prize for Science
The Milky Way was shaped by a galactic collision that occurred earlier than expected
Presentation
LIRA, a CNRS joint research unit at Paris Observatory, is a laboratory of excellence in astrophysics and instrumentation. It studies astrophysical objects, from the Solar System to our Galaxy and beyond, through five thematic areas. Through international collaboration and instrumental innovation, it pushes back the frontiers of science and contributes to the training and dissemination of knowledge.
Our projects
MIRS on the JAXA MMX mission
The Martian Moons eXploration (MMX) mission of JAXA (Japan Aerospace Exploration Agency) is the first sample-return mission from the Phobos satellite. It also includes an exploration of the Martian system. The mission’s primary objective is to decipher the origin of Martian moons, which will provide important information on planet formation and the conditions for the emergence of water on Earth-like planets.
The MIRS (MMX InfraRed Spectrometer) instrument, developed under the leadership of LESIA (now LIRA), is an imaging spectrometer that will characterize the composition of the Martian system and help select candidate sites for sample collection.
GRAVITY+
The GRAVITY instrument, installed on the European Southern Observatory’s Very Large Telescope Interferometer (VLTI/ESO), has produced spectacular and transformative results on the supermassive black hole at the centre of the Milky Way, the active nuclei of other galaxies, proto-planetary disks around young stars and exoplanets. GRAVITY+ aims to modernise both VLTI and GRAVITY to make them ≈ 100 times more sensitive, while increasing sky coverage by a factor of ≈ 100, and contrast in the vicinity of bright objects by a factor of ≈ 10. These gains will benefit all the VLTI’s current and future instruments for the next 20 years, and will perpetuate it as a unique infrastructure in the world.
All projects
Projets en développement
Projets en exploitation
Projets passés
Contacts
Contacts
Postal address
Observatoire de Paris
5, place Jules Janssen
92195 Meudon
Phone
01 45 07 77 01
Meudon site
LIRA
Observatoire de Paris
5, place Jules Janssen
92195 MEUDON Cedex
Paris site
LIRA
Observatoire de Paris
77, Avenue Denfert-Rochereau
75014 Paris
Cergy site
LIRA - Site de Neuville II
UFR Sciences et Techniques - Département de physique
5, mail Gay Lussac
95000 Neuville-sur-Oise