2019/01/21 by F. Valdés, Valdes, Francisco, Francisco Valdés
Earth and Planetary Sciences · Environmental Science · Physics and Astronomy · #Astro and Planetary Science #Atmospheric Ozone and Climate #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Isotope Analysis in Ecology #Planetary Science and Exploration #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.1901.07111
openalex publication_date 2019/01/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The distribution of solar system absolute magnitudes (H) for the near-Earth\nasteroids (NEAs) observable near opposition -- i.e. Amors, Apollos, and Atens\n(A3) -- is derived from the set of ALL currently known NEAs. The result is\nbased only on common sense assumptions of uniformly random distributions and\nthat the orbital phase space and H-magnitude distribution of known NEAs is\nrepresentative of the total population. There is no population or other\nmodeling and no assumption on albedo except in interpreting the result as a\nsize-frequency distribution (SFD). The analysis is based on the 18355 A3\nNEAs cataloged by the MPC as of June 2018. The observations from 9 of the top\nprograms (in terms of number of distinct NEAs observed) and the smaller but\ndeeper DECam NEO Survey are used, comprising 74696 measurements of 13466 NEAs\nobserved within 30 deg of opposition. The only parameter in the analysis is an\nestimate of the detection magnitude limits for each program.\n A single power-law slope for the cumulative distribution,\n\log(N<H)=0.50\±0.03H, for H < 27 is found with no evidence for additional\nstructure. A turn-over fainter than 27th magnitude may occur, but the\npopulation of known NEAs is dropping off rapidly because they are difficult to\ndetect and so possibly is a completeness effect. Connecting to the nearly\ncomplete census of the brightest/biggest NEAs (diameter > \∼2Km) provides\na normalization that estimates \∼108 A3 NEAs with H < \∼27\ncorresponding to NEAs greater than \∼10m in diameter for reasonable\ntypical albedos.\n Restricting the analysis to Earth crossing asteroids (10839 known, 7336\nselected, 36541 observed) produces the same power-law slope.\n