Hektor family explained

The Hektor family (004[1]) is a small collisional asteroid family of at least 12 known asteroids,[2] named for its largest member, the 225km (140miles)-across asteroid 624 Hektor. It lies within the larger dynamical group of Jupiter trojans, a group of asteroids in an orbital resonance with Jupiter such that they stay about 60 degrees ahead of/behind the planet in its orbit at all times in the Lagrange points L4 and L5, with the Hektor family being part of the leading cloud around L4, also known as the Greek camp. All members of the family are dark D-type asteroids with albedos of around 0.03-0.04.

An asteroid family is a group of physically-related asteroids usually created by a collision with an original larger asteroid, with the fragments continuing on similar orbits to the original. This is distinct from a dynamical group in that the members of a dynamical group only share similar orbits because of gravitational interactions with planets, which concentrate asteroids in a particular orbital range. Members of the Hektor family are both part of the wider Trojan dynamical group, and fragments of 624 Hektor. The family is considered a non-catastrophic asteroid family because 624 Hektor, its largest member, makes up nearly all of the family's total mass, rather than simply being the largest of a number of fragments each making up a small fraction of the original destroyed asteroid.[3]

The age of the family is very poorly constrained due to the lack of known small members to model, with different methods of analysis suggesting ages of 1-4 billion and 0.1-2.5 billion years.[4]

Large members

The 10 brightest Hektor family members
Name Size (km) proper
a
(AU)
proper
i
7.39 225 5.2963 0.054 19.021
12.60 21 5.2879 0.056 18.960
12.61 21 5.2875 0.052 18.994
12.73 20 5.3002 0.056 18.944
13.00 17 5.2859 0.055 18.931
13.08 17 5.2912 0.055 18.949
13.21 16 5.2879 0.055 18.925
13.35 15 5.2929 0.056 18.931
13.65 13 5.2941 0.054 18.951
13.70 13 5.2886 0.055 18.903

Notes and References

  1. Nesvorny . D. . Broz . M. . Carruba . V. . Identification and Dynamical Properties of Asteroid Families . 2015 . 10.48550/arXiv.1502.01628 . Asteroids IV . 28 July 2024.
  2. Nesvorný . David . Nesvorny HCM Asteroid Families PDS SBN Asteroid/Dust Subnode . 14 August 2020 . 10.26033/6cg5-pt13 . NASA Planetary Data System . 28 July 2024.
  3. Holsapple . K.A. . Housen . K.R. . The catastrophic disruptions of asteroids: History, features, new constraints and interpretations . Planetary and Space Science . December 2019 . 179 . 104724 . 10.1016/j.pss.2019.104724 . 30 July 2024.
  4. Rozehnal . J. . Brož . M. . Nesvorný . D. . Durda . D. D. . Walsh . K. . Richardson . D. C. . Asphaug . E. . Hektor – an exceptional D-type family among Jovian Trojans . Monthly Notices of the Royal Astronomical Society . 1 November 2016 . 462 . 3 . 2319–2332 . 10.1093/mnras/stw1719 . 30 July 2024. 1607.04677 .