TY - JOUR
T1 - The Debiased Compositional Distribution of MITHNEOS
T2 - Global Match between the Near-Earth and Main-belt Asteroid Populations, and Excess of D-type Near-Earth Objects
AU - Marsset, Michaël
AU - Demeo, Francesca E.
AU - Burt, Brian
AU - Polishook, David
AU - Binzel, Richard P.
AU - Granvik, Mikael
AU - Vernazza, Pierre
AU - Carry, Benoit
AU - Bus, Schelte J.
AU - Slivan, Stephen M.
AU - Thomas, Cristina A.
AU - Moskovitz, Nicholas A.
AU - Rivkin, Andrew S.
N1 - Funding Information:
We thank David Tholen and Julia de León for helpful discussion, and the anonymous reviewer for insightful comments and suggestions. Observations reported here were obtained at the NASA Infrared Telescope Facility, which is operated by the University of Hawaii under contract 80HQTR19D0030 with the National Aeronautics and Space Administration. The authors acknowledge the sacred nature of Maunakea and appreciate the opportunity to observe from the mountain. The MIT component of this work is supported by NASA grant 80NSSC18K0849. Any opinions, findings, and conclusions or recommendations expressed in this article are those of the authors and do not necessarily reflect the views of the National Aeronautics and Space Administration.
Publisher Copyright:
© 2022. The American Astronomical Society. All rights reserved.
PY - 2022/4/1
Y1 - 2022/4/1
N2 - We report 491 new near-infrared spectroscopic measurements of 420 near-Earth objects (NEOs) collected on the NASA InfraRed Telescope Facility as part of the MIT-Hawaii NEO Spectroscopic Survey. These measurements were combined with previously published data from Binzel et al. and bias-corrected to derive the intrinsic compositional distribution of the overall NEO population, as well as of subpopulations coming from various escape routes (ERs) in the asteroid belt and beyond. The resulting distributions reflect well the overall compositional gradient of the asteroid belt, with decreasing fractions of silicate-rich (S- and Q-type) bodies and increasing fractions of carbonaceous (B-, C-, D- and P-type) bodies as a function of increasing ER distance from the Sun. The close compositional match between NEOs and their predicted source populations validates dynamical models used to identify ERs and argues against any strong composition change with size in the asteroid belt between 1/45 km and 1/4100 m. A notable exception comes from the overabundance of D-type NEOs from the 5:2J and, to a lesser extend, the 3:1J and ν 6 ERs, hinting at the presence of a large population of small D-type asteroids in the main belt. Alternatively, this excess may indicate preferential spectral evolution from D-type surfaces to C and P types as a consequence of space weathering, or point to the fact that D-type objects fragment more often than other spectral types in the NEO space. No further evidence for the existence of collisional families in the main belt, below the detection limit of current main-belt surveys, was found in this work.
AB - We report 491 new near-infrared spectroscopic measurements of 420 near-Earth objects (NEOs) collected on the NASA InfraRed Telescope Facility as part of the MIT-Hawaii NEO Spectroscopic Survey. These measurements were combined with previously published data from Binzel et al. and bias-corrected to derive the intrinsic compositional distribution of the overall NEO population, as well as of subpopulations coming from various escape routes (ERs) in the asteroid belt and beyond. The resulting distributions reflect well the overall compositional gradient of the asteroid belt, with decreasing fractions of silicate-rich (S- and Q-type) bodies and increasing fractions of carbonaceous (B-, C-, D- and P-type) bodies as a function of increasing ER distance from the Sun. The close compositional match between NEOs and their predicted source populations validates dynamical models used to identify ERs and argues against any strong composition change with size in the asteroid belt between 1/45 km and 1/4100 m. A notable exception comes from the overabundance of D-type NEOs from the 5:2J and, to a lesser extend, the 3:1J and ν 6 ERs, hinting at the presence of a large population of small D-type asteroids in the main belt. Alternatively, this excess may indicate preferential spectral evolution from D-type surfaces to C and P types as a consequence of space weathering, or point to the fact that D-type objects fragment more often than other spectral types in the NEO space. No further evidence for the existence of collisional families in the main belt, below the detection limit of current main-belt surveys, was found in this work.
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U2 - 10.3847/1538-3881/ac532f
DO - 10.3847/1538-3881/ac532f
M3 - Article
AN - SCOPUS:85126885700
VL - 163
JO - Astronomical Journal
JF - Astronomical Journal
SN - 0004-6256
IS - 4
M1 - 165
ER -