2014/06/19 by Michael Mommert, M. Mommert, Davide Farnocchia +14 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Albedo (alchemy) #Asteroid #Astro and Planetary Science #Astrobiology #Astronomy #Astrophysics #Flux (metallurgy) #Geology #High-pressure geophysics and materials #Materials science #Meteorite #Near-Earth object #Physics #Planetary Science and Exploration #Rubble #Spitzer Space Telescope #Telescope #astro-ph.EP
paper · pdf · doi:10.1088/2041-8205/789/1/l22
published as M. Mommert et al. 2014, ApJL, 789, L22 · 20 pages, 4 figures
openalex publication_date 2014/06/19 · arxiv created 2014/06/20 · arxiv updated 2014/06/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report on observations of near-Earth asteroid 2011 MD with the Spitzer Space Telescope . We have spent 19.9 hr of observing time with channel 2 (4.5 μm) of the Infrared Array Camera and detected the target within the 2σ positional uncertainty ellipse. Using an asteroid thermophysical model and a model of nongravitational forces acting upon the object, we constrain the physical properties of 2011 MD, based on the measured flux density and available astrometry data. We estimate 2011 MD to be (6 ) m in diameter with a geometric albedo of 0.3 (uncertainties are 1σ). We find the asteroid's most probable bulk density to be (1.1 ) g cm −3 , which implies a total mass of (50–350) t and a macroporosity of ⩾65%, assuming a material bulk density typical of non-primitive meteorite materials. A high degree of macroporosity suggests that 2011 MD is a rubble-pile asteroid, the rotation of which is more likely to be retrograde than prograde.