Colors of Dynamically Associated Asteroid Pairs

TL;DR

This study investigates the colors and spectra of asteroid pairs to understand their formation, finding that pair components share similar colors and their distribution matches that of main belt asteroids, supporting a common origin.

Contribution

It provides the first comprehensive photometric and spectroscopic survey of asteroid pairs, revealing their compositional similarity and supporting formation theories like binary disruption or rotational fission.

Findings

Pair components have similar colors within uncertainties.

Color distribution of pairs matches that of all Main Belt asteroids.

Supports formation from a common progenitor, likely via binary disruption or rotational fission.

Abstract

Recent dynamical studies have identified pairs of asteroids that reside in nearly identical heliocentric orbits. Possible formation scenarios for these systems include dissociation of binary asteroids, collisional disruption of a single parent body, or spin-up and rotational fission of a rubble-pile. Aside from detailed dynamical analyses and measurement of rotational light curves, little work has been done to investigate the colors or spectra of these unusual objects. A photometric and spectroscopic survey was conducted to determine the reflectance properties of asteroid pairs. New observations were obtained for a total of 34 individual asteroids. Additional photometric measurements were retrieved from the Sloan Digital Sky Survey Moving Object Catalog. Colors or spectra for a total of 42 pair components are presented here. The main findings of this work are: (1) the components in the observed pair systems have the same colors within the uncertainties of this survey, and (2) the color distribution of asteroid pairs appears indistinguishable from that of all Main Belt asteroids. These findings support a scenario of pair formation from a common progenitor and suggest that pair formation is likely a compositionally independent process. In agreement with previous studies, this is most consistent with an origin via binary disruption and/or rotational fission.