Nature of bright C-complex asteroids

TL;DR

This study investigates bright C-complex asteroids through spectroscopic analysis, revealing their mineral composition, potential origins involving impact heating, and possible links to specific meteorite types and parent bodies.

Contribution

It provides new spectroscopic classifications of bright C-complex asteroids and links their spectral features to specific meteorite analogs and thermal alteration processes.

Findings

Bright C-complex asteroids are classified as DeMeo C-type with concave curvature.

Salts may have occurred in the parent bodies of some asteroids, indicating high-temperature processes.

Impact heating and metamorphism are key factors in the brightness of C-complex asteroids.

Abstract

Most C-complex asteroids have albedo values less than 0.1, but there are some high-albedo (bright) C-complex asteroids with albedo values exceeding 0.1. To reveal the nature and origin of bright C-complex asteroids, we conducted spectroscopic observations of the asteroids in visible and near-infrared wavelength regions. As a result, the bright B-, C-, and Ch-type (Bus) asteroids, which are subclasses of the Bus C-complex, are classified as DeMeo C-type asteroids with concave curvature, B-, Xn-, and K-type asteroids. Analogue meteorites and material (CV/CK chondrites, enstatite chondrites/achondrites, and salts) associated with these spectral types of asteroids are thought to be composed of minerals and material exposed to high temperatures. A comparison of the results obtained in this study with the SDSS photometric data suggests that salts may have occurred in the parent bodies of 24 Themis and 10 Hygiea, as well as 2 Pallas. The bright C-complex asteroids in other C-complex families were likely caused by impact heating. Bright C-complex asteroids that do not belong to any families are likely to be impact metamorphosed carbonaceous chondrites, CV/CK chondrites, or enstatite chondrites/achondrites.