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Spin rate distribution of small asteroids |
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| Authors: | P Pravec AW Harris BD Warner K Hornoch D Higgins A Galád Š Gajdoš J Világi YuN Krugly V Chiorny WR Cooney Jr D Terrell RD Stephens V Reddy F Colas R Durkee RA Koff |
| Institution: | a Astronomical Institute, Academy of Sciences of the Czech Republic, Fri?ova 1, CZ-25165 Ond?ejov, Czech Republic b Space Science Institute, 4603 Orange Knoll Ave., La Canada, CA 91011, USA c Institute of Astronomy, Charles University, V Holešovi?kách 2, CZ-18000 Prague 8, Czech Republic d Palmer Divide Observatory, 17995 Bakers Farm Rd., Colorado Springs, CO 80908, USA e Carbuncle Hill Observatory, P.O. Box 946, Coventry, RI 02816, USA f Hunters Hill Observatory, Ngunnawal, Canberra, Australia g Leura Observatory, Leura, N.S.W., Australia h Modra Observatory, Department of Astronomy, Physics of the Earth, and Meteorology, FMFI UK, Bratislava SK-84248, Slovakia i Astronomical Institute of the Slovak Academy of Sciences, SK-05960 Tatranská Lomnica, Slovak Republic j Institute of Astronomy of Kharkiv National University, Sumska Str. 35, Kharkiv 61022, Ukraine k Crimean Astrophysical Observatory, Simeiz, Crimea, Ukraine l Sonoita Research Observatory, 77 Paint Trail, Sonoita, AZ 85637, USA m Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302, USA n Goat Mountain Astronomical Research Station, Riverside Astronomical Society, 8300 Utica Avenue, Suite 105, Rancho Cucamonga, CA 91730, USA o Badlands Observatory, 12 Ash Street, P.O. Box 37, Quinn, SD 57775, USA p Department of Earth System Science and Policy, University of North Dakota, Grand Forks, ND 58202, USA q The University of Texas at Austin, Astronomy Department/McDonald Observatory, 1 University Station C1400, Austin, TX 78712-0259, USA r IMCCE-CNRS-Observatoire de Paris, 77 avenue Denfert Rochereau, 75014 Paris, France s LESIA-Observatoire de Meudon, Place Jules Janssen, 92195 Meudon, France t Shed of Science Observatory, 5213 Washburn Ave. S, Minneapolis, MN 55410, USA u Bellatrix Astronomical Observatory, Via Madonna de Loco 47, I-03023 Ceccano, Italy v Campo Catino Observatory, I-03016 Guarcino, Italy w Antelope Hills Observatory, 980 Antelope Drive West, Bennett, CO 80102, USA x Obs. Ast. de Linhaceira, Escola Superior de Tecnologia de Tomar, Instituto Politecnico de Tomar, 2300-313 Tomar, Portugal |
| Abstract: | The spin rate distribution of main belt/Mars crossing (MB/MC) asteroids with diameters 3-15 km is uniform in the range from f=1 to 9.5 d−1, and there is an excess of slow rotators with f<1 d−1. The observed distribution appears to be controlled by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect. The magnitude of the excess of slow rotators is related to the residence time of slowed down asteroids in the excess and the rate of spin rate change outside the excess. We estimated a median YORP spin rate change of ≈0.022 d−1/Myr for asteroids in our sample (i.e., a median time in which the spin rate changes by 1 d−1 is ≈45 Myr), thus the residence time of slowed down asteroids in the excess is ≈110 Myr. The spin rate distribution of near-Earth asteroids (NEAs) with sizes in the range 0.2-3 km (∼5 times smaller in median diameter than the MB/MC asteroids sample) shows a similar excess of slow rotators, but there is also a concentration of NEAs at fast spin rates with f=9-10 d−1. The concentration at fast spin rates is correlated with a narrower distribution of spin rates of primaries of binary systems among NEAs; the difference may be due to the apparently more evolved population of binaries among MB/MC asteroids. |
| Keywords: | Asteroids rotation Photometry Near-Earth objects Satellites of asteroids |
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