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The Color–Magnitude Distribution of Hilda Asteroids: Comparison with Jupiter Trojans

Wong, Ian and Brown, Michael E. (2017) The Color–Magnitude Distribution of Hilda Asteroids: Comparison with Jupiter Trojans. Astronomical Journal, 153 (2). Art. No. 69. ISSN 0004-6256. doi:10.3847/1538-3881/153/2/69.

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Current models of solar system evolution posit that the asteroid populations in resonance with Jupiter are comprised of objects scattered inward from the outer solar system during a period of dynamical instability. In this paper, we present a new analysis of the absolute magnitude and optical color distribution of Hilda asteroids, which lie in 3:2 mean-motion resonance with Jupiter, with the goal of comparing the bulk properties with previously published results from an analogous study of Jupiter Trojans. We report an updated power-law fit of the Hilda magnitude distribution through H = 14. Using photometric data listed in the Sloan Moving Object Catalog, we confirm the previously reported strong bimodality in visible spectral slope distribution, indicative of two subpopulations with differing surface compositions. When considering collisional families separately, we find that collisional fragments follow a unimodal color distribution with spectral slope values consistent with the bluer of the two subpopulations. The color distributions of Hildas and Trojans are comparable and consistent with a scenario in which the color bimodality in both populations developed prior to emplacement into their present-day locations. We propose that the shallower magnitude distribution of the Hildas is a result of an initially much larger Hilda population, which was subsequently depleted as smaller bodies were preferentially ejected from the narrow 3:2 resonance via collisions. Altogether, these observations provide a strong case supporting a common origin for Hildas and Trojans as predicted by current dynamical instability theories of solar system evolution.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Wong, Ian0000-0001-9665-8429
Brown, Michael E.0000-0002-8255-0545
Additional Information:© 2017 The American Astronomical Society. Received 2016 October 10; revised 2016 December 14; accepted 2016 December 15; published 2017 January 13.
Group:Astronomy Department
Subject Keywords:minor planets, asteroids: general
Issue or Number:2
Record Number:CaltechAUTHORS:20170120-103217399
Persistent URL:
Official Citation:Ian Wong and Michael E. Brown 2017 AJ 153 69
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73572
Deposited By: Tony Diaz
Deposited On:22 Jan 2017 17:04
Last Modified:11 Nov 2021 05:18

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