Speakers
Description
The Gaia mission has revolutionized our understanding of the Solar System by providing unprecedented astrometric and photometric data for small bodies, despite not being originally designed for this purpose. To date, Gaia has delivered high-precision astrometry for over 150,000 asteroids and photometric measurements for tens of thousands of objects, along with reflectance spectra for approximately 60,000 asteroids in the visible range. These achievements have opened new avenues for studying asteroid taxonomy, rotational properties, and phase curves. However, Gaia’s capabilities are limited to the optical domain, leaving the near-infrared (NIR) region largely unexplored from space.
GaiaNIR represents a transformative opportunity to extend Gaia’s legacy into the NIR, covering wavelengths between 0.8 and 2.5 μm. This spectral range includes diagnostic absorption features of silicates (near 0.9 and 2.0 μm), hydrated minerals, and volatiles such as water ice (around 1.5 and 2.0 μm), as well as providing critical information on continuum slopes. These measurements are essential for disentangling compositional classes within the asteroid belt and for probing the distribution of primitive and thermally altered materials. While a single broad NIR filter would enable improved phase-curve studies and rotational characterization, the real scientific breakthrough lies in spectroscopic capability. Low-resolution spectra across this range would allow robust taxonomic classification and compositional mapping, complementing ground-based surveys and addressing key questions about Solar System formation and evolution.
GaiaNIR’s expected sensitivity, assuming performance comparable to Gaia, would enable characterization of objects down to absolute magnitude Hr ≈ 17, corresponding to diameters of several kilometers in the main belt. This complements the Rubin Observatory’s LSST, which will complete the inventory of main-belt asteroids down to Hr ≈ 20 (∼1 km), and surpasses the spectrophotometric capabilities of missions like Euclid. By combining GaiaNIR’s NIR spectroscopy with LSST’s deep optical survey, we can achieve an unprecedented multi-wavelength dataset for hundreds of thousands of small bodies, enabling studies of space weathering, thermal evolution, and volatile retention across diverse populations.
In this presentation, we will review Gaia’s contributions to Solar System science in the visible domain and outline the scientific objectives of GaiaNIR. We will discuss its potential to characterize asteroid composition, constrain dynamical families, and identify reservoirs of volatiles, as well as its synergy with upcoming surveys. GaiaNIR will not only fill a critical observational gap but also provide a cornerstone for comparative planetology, linking small-body populations to the processes that shaped the early Solar System
