Hektor - an exceptional D-type family among Jovian Trojans

Abstract

In this work, we analyze Jovian Trojans in the space of suitable resonant elements and we identify clusters of possible collisional origin by two independent methods: the hierarchical clustering and a so-called "randombox". Compared to our previous work (Brož and Rozehnal 2011), we study a twice larger sample. Apart from Eurybates, Ennomos and $1996\mathrm{RJ}$ families, we have found three more clusters --- namely families around asteroids (20961)~Arkesilaos, (624)~Hektor in the $L_4$ libration zone and (247341)~$2001\mathrm{U}{\mathrm{V}}_{209}$ in $L_5$. The families fulfill our stringent criteria, i.e. a high statistical significance, an albedo homogeneity and a steeper size-frequency distribution than that of background. In order to understand their nature, we simulate their long term collisional evolution with the Boulder code (Morbidelli et al. 2009) and dynamical evolution using a modified SWIFT integrator (Levison and Duncan, 1994). Within the framework of our evolutionary model, we were able to constrain the the age of the Hektor family to be either 1 to 4 Gyr or, less likely, 0.1 to 2.5 Gyr, depending on initial impact geometry. Since (624) Hektor itself seems to be a bilobed--shape body with a satellite (Marchis et al. 2014), i.e. an exceptional object, we address its association with the D--type family and we demonstrate that the moon and family could be created during a single impact event. We simulated the cratering event using a Smoothed Particle Hydrodynamics (SPH, Benz and Asphaug, 1994). This is also the first case of a family associated with a D--type parent body.

arXiv commentaccepted to MNRAS

References in corpus (17)

• Catastrophic disruptions revisited
• Asteroids Were Born Big
• High order symplectic integrators for perturbed Hamiltonian systems
• Capture of Trojans by Jumping Jupiter
• Evidence from the asteroid belt for a violent past evolution of Jupiter's orbit
• Final Stages of Planet Formation
• Standing on the shoulders of giants: Trojan Earths and vortex trapping in low mass self-gravitating protoplanetary disks of gas and solids
• NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results
• Near-Infrared Spectroscopy of Trojan Asteroids: Evidence for Two Compositional Groups
• WISE/NEOWISE Observations of the Jovian Trojans: Preliminary Results
• Constraining the cometary flux through the asteroid belt during the late heavy bombardment
• WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy
• The Puzzling Mutual Orbit of the Binary Trojan Asteroid (624) Hektor
• Constraints on the original ejection velocity fields of asteroid families
• The Eos family halo
• Asteroids Observed by The Sloan Digital Sky Survey
• Eurybates - the only asteroid family among Trojans?

Cited by in corpus (14)

• Dynamical Evolution of the Early Solar System
• Origin and evolution of long-period comets
• On the Ages of Resonant, Eroded and Fossil Asteroid Families
• Toward Understanding the Origin of Asteroid Geometries: Variety in Shapes Produced by Equal-Mass Impacts
• Stability of Jovian Trojans and their collisional families
• Origin and Evolution of Jupiter's Trojan Asteroids
• Implications for the collisional strength of Jupiter Trojans from the Eurybates family
• The young Hobson family: Possible binary parent body and low-velocity dispersal
• Astrocladistics of the Jovian Trojan Swarms
• Rotationally-resolved spectroscopy of Jupiter Trojans (624) Hektor and (911) Agamemnon
• Orbital Stability Close to Asteroid 624 Hektor using the Polyhedral Model
• Photometric Confirmation and Characterization of the Ennomos Collisional Family in the Jupiter Trojans
• A pair of Jovian Trojans at the L4 Lagrange point
• Ultraviolet Spectroscopy of Lucy Mission Targets with the Hubble Space Telescope