2012/10/02 by F. Marchis, Franck Marchis, J. Emilio Enriquez +20 · 8 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #High-pressure geophysics and materials #Planetary Science and Exploration #astro-ph.EP
paper · pdf · doi:10.1016/j.icarus.2012.09.013
published as Icarus, Volume 221, Issue 2, November-December 2012, Pages 1130-1161 · 69 pages, 5 Figures, 8 Tables
openalex publication_date 2012/10/02 · arxiv created 2016/04/19 · arxiv updated 2016/04/20 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Photometric lightcurves were also obtained for 14 of them during the Spitzer observations to provide the context of the observations and reliable estimates of their absolute magnitudes. The extracted mid-IR spectra were analyzed using a modified standard thermal model (STM) and a thermophysical model (TPM) that takes into account the shape and geometry of the large primary at the time of the Spitzer observation. We derived a reliable estimate of the size, albedo, and beaming factor for each of these asteroids, representing three main taxonomic groups: C, S, and X. For large (volume-equivalent system diameter Deq \lt 130 km) binary asteroids, the TPM analysis indicates a low thermal inertia (Γ < ∼100 J s-1/2K-1m-2) and their emissivity spectra display strong mineral features, implying that they are covered with a thick layer of thermally insulating regolith. The smaller (surface-equivalent system diameter Deff \lt17 km) asteroids also show some emission lines of minerals, but they are significantly weaker, consistent with regoliths with coarser grains, than those of the large binary asteroids. The average bulk densities of these multiple asteroids vary from 0.7-1.7 g/cm3 (P-, C- type) to ∼2 g/cm3 (S-type). The highest density is estimated for the M-type (22) Kalliope (3.2 ± 0.9 g/cm3). The spectral energy distributions (SED) and emissivity spectra, made available as a supplement document, could help to constrain the surface compositions of these asteroids.