Surface composition and dynamical evolution of two retrograde objects in the outer solar system: 2008 YB3 and 2005 VD

Abstract

Most of the objects in the trans-Neptunian belt (TNb) and related populations move in prograde orbits with low eccentricity and inclination. However, the list of icy minor bodies moving in orbits with an inclination above 40 deg. has increased in recent years. The origin of these bodies, and in particular of those objects in retrograde orbits, is not well determined, and different scenarios are considered. In this paper, we present new observational and dynamical data of two objects in retrograde orbits, 2008 YB3 and 2005 VD. We find that the surface of these extreme objects is depleted of ices and does not contain the 'ultra-red' matter typical of some Centaurs. Despite small differences, these objects share common colors and spectral characteristics with the Trojans, comet nuclei, and the group of grey Centaurs. All of these populations are supposed to be covered by a mantle of dust responsible for their reddish- to neutral-color. To investigate if the surface properties and dynamical evolution of these bodies are related, we integrate their orbits for 10^(8) years to the past. We find a remarkable difference in their dynamical evolutions: 2005 VD' s evolution is dominated by a Kozai resonance with planet Jupiter while that of 2008 YB3 is dominated by close encounters with planets Jupiter and Saturn. Our models suggest that the immediate site of provenance of 2005 VD is the in the Oort cloud, whereas for 2008 YB3 it is in the trans-Neptunian region. Additionally, the study of their residence time shows that 2005 VD has spent a larger lapse of time moving in orbits in the region of the giant planets than 2008 YB3. Together with the small differences in color between these two objects, with 2005 VD being more neutral than 2008 YB3, this fact suggests that the surface of 2005 VD has suffered a higher degree of processing, probably related to cometary activity episodes.

9 pages, 5 figures, Accepted by Astronomy and Astrophysics: 28 November 2012

References in corpus (10)

• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Near-Infrared Spectroscopy of Trojan Asteroids: Evidence for Two Compositional Groups
• Reopening the TNOs Color Controversy: Centaurs Bimodality and TNOs Unimodality
• Colors and taxonomy of Centaurs and Trans-Neptunian Objects
• An Oort cloud origin for the high-inclination, high-perihelion Centaurs
• The Colors of Extreme Outer Solar System Objects
• Visible spectroscopy of the new ESO Large Program on trans-Neptunian objects and Centaurs: final results
• NICS-TNG infrared spectroscopy of trans-neptunian objects 2000 EB173 and 2000 WR106
• The spectrum of (136199) Eris between 350 and 2350 nm: Results with X-Shooter
• Visible spectroscopy in the neighborhood of 2003 EL61

Cited by in corpus (8)

• Color Systematics of Comets and Related Bodies
• Asteroids in retrograde resonance with Jupiter and Saturn
• Large retrograde Centaurs: visitors from the Oort cloud?
• Absolute magnitudes and phase coefficients of trans-Neptunian objects
• A Statistical Review of Light Curves and the Prevalence of Contact Binaries in the Kuiper Belt
• Dynamical Lifetimes of Asteroids in Retrograde Orbits
• Planck intermediate results. LIII. Detection of velocity dispersion from the kinetic Sunyaev-Zeldovich effect
• Small solar system objects on highly inclined orbits: Surface colours and lifetimes