Part of the largest cluster of asteroid families in the asteroid belt
TheNysa family (adj.Nysian;FIN:405) is part of theNysa–Polana complex, the largest cluster ofasteroid families in theasteroid belt.[1]: 23 It is located in theinner region of the asteroid belt, orbiting the Sun between 2.41 and 2.5 AU. Asteroids in this complex haveeccentricities between 0.12 and 0.21 andinclinations of 1.4 to 4.3.[2] The family derives its name from its most massive member,44 Nysa. It has also been known as theHertha family(adj. Herthian) named after135 Hertha.
Asteroids in this complex are typically divided into the stony Nysa and carbonaceous Polana subgroups, two mineralogically different families:[3]
The much brighterS-type Nysian subgroup (i.e. the Nysa family, in the narrower sense) includes44 Nysa and135 Hertha.
In the low-albedo subgroup of the complex lies thePolana family(adj Polanian), a family of darkF-type asteroids named after142 Polana, the largest asteroid in this section.[4] New JWST Spectroscopy of (142) Polana suggests that the near-Earth asteroids (101955) Bennu, which was the target of NASA’s OSIRIS-REx mission, and (162173) Ryugu, which was the target of JAXA’s Hayabusa-2 mission, are also members of this family.[5] More recently an additional family, theEulalia family has also been identified inside this subgroup.[3][1]: 4, 8
^abWalsh, Kevin J.; Delbó, Marco; Bottke, William F.; Vokrouhlický, David; Lauretta, Dante S. (July 2013). "Introducing the Eulalia and new Polana asteroid families: Re-assessing primitive asteroid families in the inner Main Belt".Icarus.225 (1):283–297.arXiv:1305.2821.Bibcode:2013Icar..225..283W.doi:10.1016/j.icarus.2013.03.005.
