Astronomy8 papers
Binary asteroids
IŽ
Ivana Milić Žitnik
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Asteroid pairs: A complex picture
P. Pravec et al. (2019)
- Published
- Nov 1, 2019
- Journal
- Icarus · Vol. 333
- DOI
- 10.1016/j.icarus.2019.05.014
At a Glance
Survey of 93 asteroid pairs reveals widespread rotational-fission signatures, frequent paired binaries, and puzzling high–mass-ratio outliers.
Summary
Using a greatly expanded sample of 93 genetically related asteroid pairs, this work shows that most pairs obey the predicted link between primary spin rate and pair mass ratio, strengthening rotational fission as the dominant formation path. It also uncovers a surprisingly high incidence of binaries (and even triples) among the fastest-rotating primaries, implying that pair formation often involves more complex multi-body evolution than a simple two-body split. The paper highlights four secure, high–mass-ratio pairs that fall outside existing theory, and explores (but cannot yet physically justify) an extreme scenario where a flattened parent fissions and the components reshape to enable near-equal-mass escape. Overall, it reframes asteroid pairs as a diverse population that constrains YORP-driven fission, post-fission spin/orbit evolution, and the boundary between “pairs,” “clusters,” and “paired binaries.”
Method Snapshot
Combined backward orbit integrations with Yarkovsky-enabled clone ensembles and multi-apparition photometric lightcurve analysis (plus limited TPM/WISE refinement) to derive ages, spins, poles, and mass ratios.
Background
Comfort with asteroid dynamics (Yarkovsky/YORP, resonances), lightcurve-based rotation/shape inference, and basic binary-asteroid angular-momentum concepts.