Size-Based Spectrophotometric Analysis of the Polana-Eulalia Complex

TL;DR

This study investigates how the visible spectrophotometric slopes of asteroid families in the Polana-Eulalia Complex vary with size, revealing family-specific trends and potential causes for slope differences, which may inform asteroid source identification.

Contribution

It presents the first size-based analysis of spectrophotometric slopes within the Polana-Eulalia Complex using SDSS and Gaia data, highlighting size-related slope variability and family differences.

Findings

Eulalia family members have lower slopes than Polana members.

Size < 9 km correlates with slope differences.

No statistically significant slope distinction between families.

Abstract

The Polana-Eulalia Complex (PEC) is an Inner Main Belt, C-complex asteroid population that may be the source of the near-Earth asteroid spacecraft mission targets (101955) Bennu and (162173) Ryugu. Here, we report a size-based investigation of the visible (VIS; 0.47 -- 0.89 um) spectrophotometric slopes of the PEC's constituent families, the New Polana and Eulalia Families. Using two releases of the Sloan Digital Sky Survey's Moving Object Catalog as well as the 3rd data release of the Gaia catalog, we present evidence of size-based slope variability within each family. We find that Eulalia family members exhibit lower average slopes than Polana family members in all catalogs' samples, particularly for objects < 9 km in diameter. We are unable to conclude that VIS slope distinguishability between the families is statistically significant, but we explore a potential cause of the bulk slope differences between the PEC families, in addition to providing commentary on size-slope trends generally.