Compositional properties of planet-crossing asteroids from astronomical surveys^★

¹ Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, France
e-mail: alexey.v.sergeyev@gmail.com
² V. N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv 61022, Ukraine
³ European Southern Observatory (ESO), Alonso de Cordova 3107, 1900 Casilla Vitacura, Santiago, Chile
⁴ Department of Earth, Atmospheric and Planetary Sciences, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
⁵ Astronomical Institute, Academy of Sciences of the Czech Republic, 25165 Ondřejov, Czech Republic
⁶ INAF – Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monte Porzio Catone, Italy
⁷ Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
⁸ INAF – Osservatorio Astronomico di Roma, Monte Porzio Catone (RM), Italy
⁹ INAF – Department of Physics and Astronomy, University of Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy
¹⁰ Agenzia Spaziale Italiana (ASI), Via del Politecnico, 00133 Roma, Italy

Received: 13 March 2023
Accepted: 18 July 2023

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 7401 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 dependence 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.