Hektor - an exceptional D-type family among Jovian Trojans

J. Rozehnal, M. Brož, D. Nesvorný, D. D. Durda, K. Walsh, D. C. Richardson, E. Asphaug

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Abstract

In this work, we analyse 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, we study a twice larger sample. Apart from Eurybates, Ennomos and 1996 RJ families, we have found three more clusters - namely families around asteroids (20961) Arkesilaos, (624) Hektor in the L4 libration zone and (247341) 2001UV209 in L5. 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 and dynamical evolution using a modified SWIFT integrator. Within the framework of our evolutionary model, we were able to constrain the age of the Hektor family to be either 1-4 Gyr or, less likely, 0.1-2.5 Gyr, depending on initial impact geometry. Since (624) Hektor itself seems to be a bilobed-shape body with a satellite, 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. This is also the first case of a family associated with a D-type parent body.

Original languageEnglish (US)
Article numberstw1719
Pages (from-to)2319-2332
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume462
Issue number3
DOIs
StatePublished - Nov 1 2016

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Keywords

  • Celestial mechanics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Rozehnal, J., Brož, M., Nesvorný, D., Durda, D. D., Walsh, K., Richardson, D. C., & Asphaug, E. (2016). Hektor - an exceptional D-type family among Jovian Trojans. Monthly Notices of the Royal Astronomical Society, 462(3), 2319-2332. [stw1719]. https://doi.org/10.1093/mnras/stw1719