# # Program information file # PROGRAM_ID 2024B009 PROGRAM_TITLE Spectroscopic characterisation of the first D-type families of the main belt. PROGRAM_INV1 Chrysa Avdellidou PROGRAM_INV2 Marco Delbo PROGRAM_INV3 Kevin Walsh PROGRAM_INV4 Sunao Hasegawa PROGRAM_INV5 Ullas Bhat PROGRAM_SCICAT main-belt / Trojan asteroids PROGRAM_ABSTRACT_BEG The primitive asteroid population of the main belt includes objects with low geometric visible albedos [pV<0.10] and red spectral slopes. These asteroids are classified as X/P, T, D- and Z-types for increasingly spectral slope in the wavelength range between 0.4-2.5 um. Dynamical evolution models of the early Solar System show that such Z- and D-types originate from the transneptunian region and were implanted into the asteroid main belt due to the orbital instability of the giant planets. Although we observe an increasing slope between these primitive, dark populations [X/P, T, D and Z-types], we lack an understanding of what actually causes this spectral variation. An excess of D-type objects has been observed in near-Earth space compared to the main belt. Although these objects should originate from main belt sources, previous spectroscopic and spectrophotometric surveys have not identified any primitive, dark, red-sloped family of this type. We discovered that four families appear to be D/T-types of the BusDemeo taxonomic scheme showing red slopes. This is the very first discovery of potential D-type families in the main belt. This proposal aims to characterise these four families in the near-infrared wavelengths to confirm the Gaia DR3 findings and provide a full spectrum in the visible and the near-infrared. We request time to observe 12 objects from all for families using IRTF/SpeX instrument [PRISM 0.7--2.52 um, dichroic 0.7] with the 0.8x15' slit. We will use MORIS for guiding, since most of our targets are faint [>17mag]. The IRTF near-infrared spectra obtained at 0.7--2.5 um will be combined with the Gaia DR3 VIS spectra and with existing ground-based spectrophotometry. Each combined spectrum will be then classified in the Bus-DeMeo taxonomy. PROGRAM_ABSTRACT_END