THE ALBEDO DISTRIBUTION of NEAR EARTH ASTEROIDS

Edward L. Wright, Amy Mainzer, Joseph Masiero, Tommy Grav, James Bauer

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

The cryogenic Wide-field Infrared Survey Explorer (WISE) mission in 2010 was extremely sensitive to asteroids and not biased against detecting dark objects. The albedos of 428 near Earth asteroids (NEAs) observed by WISE during its fully cryogenic mission can be fit quite well by a three parameter function that is the sum of two Rayleigh distributions. The Rayleigh distribution is zero for negative values, and follows for positive x. The peak value is at x = σ, so the position and width are tied together. The three parameters are the fraction of the objects in the dark population, the position of the dark peak, and the position of the brighter peak. We find that 25.3% of the NEAs observed by WISE are in a very dark population peaking at p V = 0.030, while the other 74.7% of the NEAs seen by WISE are in a moderately dark population peaking at p V = 0.168. A consequence of this bimodal distribution is that the congressional mandate to find 90% of all NEAs larger than 140 m diameter cannot be satisfied by surveying to H = 22 mag, since a 140 m diameter asteroid at the very dark peak has H = 23.7 mag, and more than 10% of NEAs are darker than p V = 0.03.

Original languageEnglish (US)
Article number79
JournalAstronomical Journal
Volume152
Issue number4
DOIs
StatePublished - Oct 2016
Externally publishedYes

Keywords

  • asteroids: general
  • minor planets

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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