Keck, Gemini, and Palomar 200-inch visible photometry of red and very-red Neptunian Trojans

Abstract

Neptunian Trojans (NTs), trans-Neptunian objects in 1:1 mean-motion resonance with Neptune, are generally thought to have been captured from the original trans-Neptunian protoplanetary disk into co-orbital resonance with the ice giant during its outward migration. It is possible, therefore, that the colour distribution of NTs is a constraint on the location of any colour transition zones that may have been present in the disk. In support of this possible test, we obtained $g$, $r$, and $i$-band observations of 18 NTs, more than doubling the sample of NTs with known visible colours to 31 objects. Out of the combined sample, we found $\approx$4 objects with $g$-$i$ colours of $>$1.2 mags placing them in the very red (VR) category as typically defined. We find, without taking observational selection effects into account, that the NT $g$-$i$ colour distribution is statistically distinct from other trans-Neptunian dynamical classes. The optical colours of Jovian Trojans and NTs are shown to be less similar than previously claimed with additional VR NTs. The presence of VR objects among the NTs may suggest that the location of the red to VR colour transition zone in the protoplanetary disk was interior to 30-35 au.

arXiv comment8 pages, 3 figures, 3 tables, accepted for publication in MNRAS:Letters

References in corpus (25)

• Cosmic-Ray Rejection by Laplacian Edge Detection
• Protoplanetary Disks and Their Evolution
• The Pan-STARRS1 Photometric System
• Empirical Color Transformations Between SDSS Photometry and Other Photometric Systems
• Solar System evolution from compositional mapping of the asteroid belt
• The Absolute Magnitude of the Sun in Several Filters
• A Correlation Between Inclination and Color in the Classical Kuiper Belt
• Kuiper belt: formation and evolution
• Colours of minor bodies in the outer solar system - II: A statistical analysis revisited
• A hypothesis for the color bimodality of Jupiter Trojans
• The Color Differences of Kuiper Belt Objects in Resonance with Neptune
• The bimodal color distribution of small Kuiper Belt objects
• A search of the full six years of the Dark Energy Survey for outer Solar System objects
• Col-OSSOS: The Colours of the Outer Solar System Origins Survey
• The differing magnitude distributions of the two Jupiter Trojan color populations
• OSSOS XX: The Meaning of Kuiper Belt Colors
• The color-magnitude distribution of small Jupiter Trojans
• High Efficiency UV/Optical/NIR Detectors for Large Aperture Telescopes and UV Explorer Missions: Development of and Field Observations with Delta-doped Arrays
• Characterization of the Nucleus, Morphology and Activity of Interstellar Comet 2I/Borisov by Optical and Near-Infrared GROWTH, Apache Point, IRTF, ZTF and Keck Observations
• The Trojan Color Conundrum
• Initial Characterization of Active Transitioning Centaur, P/2019 LD2 (ATLAS), using Hubble, Spitzer, ZTF, Keck, APO and GROWTH Visible & Infrared Imaging and Spectroscopy
• 2011 HM102: Discovery of a High-Inclination L5 Neptune Trojan in the Search for a post-Pluto New Horizons Target
• The discovery and characterization of a kilometre sized asteroid inside the orbit of Venus
• OSSOS: The Eccentricity and Inclination Distributions of the Stable Neptunian Trojans
• Evidence for Color Dichotomy in the Primordial Neptunian Trojan Population

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