Compositional properties of planet-crossing asteroids from astronomical surveys

TL;DR

This study characterizes the compositions of a large sample of planet-crossing asteroids using survey data, revealing compositional trends related to their orbits and physical properties, which aids understanding of their origins and potential threats.

Contribution

It provides an extensive taxonomic classification of over 7,400 NEOs using multi-survey data, and analyzes compositional dependencies on orbital parameters, enhancing knowledge of asteroid diversity and distribution.

Findings

Confirmed perihelion dependence of spectral slope in S-type NEOs.

Identified clustering of A-type NEOs around 1.5-2 AU.

Provided updated photometry for 470 NEOs and classified 7,401 NEOs.

Abstract

Context. The study of planet-crossing asteroids is of both practical and fundamental importance. As they are closer than asteroids in the Main Belt, we have access to a smaller size range, and this population frequently impacts planetary surfaces and can pose a threat to life. Aims. We aim to characterize the compositions of a large corpus of planet-crossing asteroids and to study how these compositions are related to orbital and physical parameters. Methods. We gathered publicly available visible colors of near-Earth objects (NEOs) from the Sloan Digital Sky Survey (SDSS) and SkyMapper surveys. We also computed SDSS-compatible colors from reflectance spectra of the Gaia mission and a compilation of ground-based observations. We determined the taxonomy of each NEO from its colors and studied the distribution of the taxonomic classes and spectral slope against the orbital parameters and diameter. Results. We provide updated photometry for 470 NEOs from the SDSS, and taxonomic classification of 7,401 NEOs. We classify 42 NEOs that are mission-accessible, including six of the seven flyby candidates of the ESA Hera mission. We confirm the perihelion dependance of spectral slope among S-type NEOs, likely related to a rejuvenation mechanism linked with thermal fatigue. We also confirm the clustering of A-type NEOs around 1.5-2 AU, and predict the taxonomic distribution of small asteroids in the NEO source regions in the Main Belt.