Colors and Shapes of the Irregular Planetary Satellites

Abstract

It is widely recognized that the irregular satellites of the giant planets were captured from initially heliocentric orbits. However, the mechanism of capture and the source region from which they were captured both remain unknown. We present an optical color survey of 43 irregular satellites of the outer planets conducted using the LRIS camera on the 10-meter telescope at the Keck Observatory in Hawaii. The measured colors are compared to other planetary bodies in search for similarities and differences that may reflect upon the origin of the satellites. We find that ultrared matter (with color index B-R $\ge$ 1.6), while abundant in the Kuiper belt and Centaur populations, is depleted from the irregular satellites. We also use repeated determinations of the absolute magnitudes to make a statistical estimate of the average shape of the irregular satellites. The data provide no evidence that the satellites and the main-belt asteroids are differently shaped, consistent with collisions as the major agent shaping both.

arXiv comment35 pages, 10 figures

References in corpus (12)

• The Active Centaurs
• The colours of the Sun
• Population and Size Distribution of Small Jovian Trojan Asteroids
• Irregular Satellites of the Planets: Products of Capture in the Early Solar System
• Color Systematics of Comets and Related Bodies
• Reanalyzing the visible colors of Centaurs and KBOs: what is there and what we might be missing
• Photometric Survey of the Irregular Satellites
• The bimodal color distribution of small Kuiper Belt objects
• The shape distribution of asteroid families -- evidence for evolution driven by small impacts
• The Trojan Color Conundrum
• A deeper look at the colors of the Saturnian irregular satellites
• Photometry of Irregular Satellites of Uranus and Neptune

Cited by in corpus (11)

• Kuiper belt: formation and evolution
• OSSOS XX: The Meaning of Kuiper Belt Colors
• Evidence for sulfur-bearing species on Callisto's leading hemisphere: Sourced from Jupiter's irregular satellites or Io?
• Longitudinal Variation of H${}_2$O Ice Absorption on Miranda
• An Astrometric Approach to Measuring the Color of an Object
• Irregular moons possibly injected from the outer solar system by a stellar flyby
• Colors of Irregular Satellites of Saturn with DECam
• Retrograde predominance of small saturnian moons reiterates a recent retrograde collisional disruption
• Nereid as a Regular Satellite of Neptune
• Kilometre-scale Jovian moon characterized for a potential JUICE flyby
• New Moons of Uranus and Neptune from Ultra-Deep Pencil Beam Surveys