# # Program information file # PROGRAM_ID 2022A049 PROGRAM_TITLE SpeX validation of the high abundance of olivine-rich asteroids from Gaia spectra. PROGRAM_INV1 Marco Delbo PROGRAM_INV2 Jules Bourdelle de Micas PROGRAM_INV3 Chrysa Avdellidou PROGRAM_INV4 Paolo Tanga PROGRAM_INV5 Sonia Fornasier PROGRAM_SCICAT main-belt / Trojan asteroids PROGRAM_ABSTRACT_BEG During the validation process of the asteroid spectra obtained by ESA's Gaia space mission, an unexpected overabundance of asteroids with a spectral class that indicates an olivine-rich composition was identified. SpeX at the IRTF is asked for confirming Gaia olivine-rich asteroids. If validated, this finding would solve the 'missing mantle problem' of planetary science in a direction opposite to our current understanding. Namely, it has been shown that the currently-perceived low abundance of olivine-rich asteroids is because differentiated asteroids, that should have formed during the planetary formation era of our solar system, are not present in the main belt. On the other hand, Gaia's spectra indicate an abundance of olivine-rich asteroids that is 10 times larger than what previously found, in particular within some asteroids collisional families, which are logical to be expected to form from the break up of a differentiated parent body. Moreover, the abundance of Gaia olivine-rich asteroid is strongly dependent on the heliocentric distance, contrasting with previous findings. If the Gaia data will be positively validated by SpeX observations, the Gaia and IRTF data could finally show the presence of the long-searched-for differentiated asteroids. PROGRAM_ABSTRACT_END