Cybele orbital region

The Cybele group, usually not considered part of the main belt, is located beyond the 2J:-1A mean motion resonance in semi-major axis and its orbital region is usually defined to lie between 3.27 and 3.70 AU in proper a and to i < 30o.  Currently, there are 1111 asteroid in the Cybele orbital region.  The largest collisional family in the region is associated with (87) Sylvia, a binary asteroid (Vokrouhlický et al. 2010).  The same authors investigated the orbital region of the two other large binary asteroids in the region, (107) Camila and (121) Hermione, that are currently not part of any recognizable family.  They concluded that, while it is possible that Yarkovsky/YORP driven mobility in the orbital region of these asteroids may have depleted possible local collisional families in time-scales of 4 Byr, other mechanisms, such as resonance sweeping or other perturbing effects associated with the late Jupiter's inward migration may have been at play in the region in order to justify the current lack of dynamical groups.  The AstDyS report three more families in the region of the Cybele group: Huberta, Ulla, and (2000) EK76.  No halo group was found for the (2000) EK76 AstDyS cluster, that will not therefore be treated in this section.  There were 128 asteroids in our multi-domain sample in this region; the vast majority of asteroids in the Cybele region are dark objects, typical of CX-complex taxonomy.

Cybele density
Cybele aiz
Cybele pv
Contour plot of the number density of asteroids in the proper element sample. 
Superimposed, we display the orbital location of asteroids of families in the CX-complex (plus signs) and S-complex (circles).
An (a*,i-z) projection of Cybele-region
asteroids in the in our multi-domain sample.
A histogram of number frequency values ni/NTot as a function of geometric albedo pV for Cybele-region asteroids in our multi-domain sample.

First halo
member
dmd [m/s]
Number of
members
Spectral
complex
Number of
SDSS-MOC4
interlopers
Number of
albedo
interlopers
(87) Sylvia: (18959)
395
13
CX
0
1
(260) Huberta: (260)
495
4
CX
0
1
(909) Ulla: (85036)
    220
  4
CX
0
0