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The 1986 DA and 1986 EB: M-class asteroids in near-Earth orbitsThe Earth-approaching asteroid population is composed of asteroids in orbits with short lifetimes compared with the age of the solar system. These objects which are comprised of Aten, Apollo, and Amor asteroids must be replenished from either cometary or mainbelt asteroid sources since lifetimes against collision with or ejection by a planet are on the order of 10 to 100 million years. The physical study of Earth-approaching asteroids is constrained by the generally long period between favorable apparitions and poorly known orbits. Broadband spectrophotometry on the Johnson UBVR system and the Eight-Color Asteroid Survey system were obtained at Kitt Peak National Observatory and on the Johnson JHK system and at 10 and 20 microns at the NASA Infrared Telescope Facility at Mauna Kea Observatory. These observations were used to determine the absolute visual magnitudes and to derive the visual geometric albedos and diameters on the IRAS system. The spectral reflectance properties and geometric albedos of the M-class asteroids are consistent compositions analogous to the iron nickel meteorites or the enstatite-metal assemblages of the enstatite chondrites. The issue of the source(s) of the near-Earth asteroids population was examined by comparing the classifications on the scheme employed by Gradie and Tedesco of 38 such asteroids. Most of the near-Earth objects is indeed the asteroid belt as the observations suggest, then a method for removing extinct nuclei of short period comets must be found since the rate of production of short period comets from the long period comets is relatively large.
Document ID
19870013938
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Gradie, Jonathan (Hawaii Inst. of Geophysics Honolulu., United States)
Tedesco, Edward (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
September 5, 2013
Publication Date
May 1, 1987
Publication Information
Publication: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986
Subject Category
Astrophysics
Accession Number
87N23371
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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