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.
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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).
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An (a*,i-z) projection of Cybele-region
asteroids in the in our multi-domain sample.
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A histogram of number frequency values ni/NTot as a function of geometric albedo pV for Cybele-region asteroids in our multi-domain sample.
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First halo
member
|
dmd [m/s]
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Number of
members
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Spectral
complex
|
Number of
SDSS-MOC4
interlopers
|
Number of
albedo
interlopers
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(87) Sylvia: (18959)
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395
|
13
|
CX
|
0
|
1
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(260) Huberta: (260)
|
495
|
4
|
CX
|
0
|
1
|
(909) Ulla: (85036)
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220
|
4
|
CX
|
0
|
0
|