Photometric analysis of asteroids in the Phocaea region

TL;DR

This study analyzes the physical properties of 44 Phocaea region asteroids using photometric data, revealing the influence of Yarkovsky and YORP effects and suggesting a link to H chondrite meteorites, which helps understand NEA origins.

Contribution

It provides new physical property measurements for Phocaea family members and links their composition to H chondrites, highlighting their role as potential NEA sources.

Findings

Yarkovsky and YORP effects significantly influence Phocaea asteroids.

Estimated densities suggest rubble pile structures.

The Phocaea family likely originated from H chondrite-like parent material.

Abstract

The Phocaea asteroid family, one of the large ancient families located in the inner main belt, may be the sources of near-Earth asteroids (NEAs) due to the nearby 3:1 mean motion resonance with Jupiter, the v6 secular resonance, and the Yarkovsky and YORP effects. Thus, understanding the influence of the Yarkovsky and YORP effects on the Phocaea family is one of the keys to figuring out the source of NEAs. However, the physical properties of most of the Phocaea family members are unknown at present. We perform a photometric analysis for 44 asteroids in the Phocaea region using photometric data obtained by ground-based and space-based telescopes (i.e., TESS and Gaia). Based on the derived physical properties, we find significant footprints of the Yarkovsky and YORP effects on the Phocaea family members. Selecting five asteroids nearby the inside boundary of the V-shape in the absolute-magnitude semimajor-axis (H, a) space, we estimate their densities considering their migration in semimajor-axis arises from the Yarkovsky effect. The bulk density of (852) Wladilena ({3.54 g/cm3) suggests a link to the H chondrite meteorites. Incorporating the grain density of the H chondrites, we estimate the macroporosities of the asteroids (290) Bruna, (1164) Kobolda, and (587) Hypsipyle, respectively 41%, 47%, and 65%, implying rubble pile structures. Considering the H chondrites link to asteroid (25) Phocaea, we suggest the parent body of the Phocaea family has been composed of H chondrite like material and the Phocaea family may be one of the sources of H chondrite meteorites.