Physical properties of near-Earth Asteroid (33342) 1998 WT24

Michael W. Busch, Lance A.M. Benner, Steven J. Ostro, Jon D. Giorgini, Raymond F. Jurgens, Randy Rose, Daniel J. Scheeres, Christopher Magri, Jean Luc Margot, Michael C. Nolan, Alice A. Hine

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

During its close Earth approach in 2001, the E-class near-Earth Asteroid (33342) 1998 WT24 was the focus of extensive radar, optical, and thermal infrared observations. We present a physical model of this object, estimated from Arecibo and Goldstone radar images that cover multiple rotations and span over 100° of sky motion. The asteroid has an equivalent diameter of 415 ± 40   m and a diffuse radar scattering law that is identical in both senses of circular polarization, implying a surface that is extremely rough on centimeter-to-decimeter scales. The shape is dominated by three large basins, which may be impact craters or a relic of past dynamical disruption of the object. Analysis of YORP perturbations on WT24's spin state predicts that the asteroid's spin rate is decreasing at a rate of 2 × 10-7   deg s-1 yr-1. Simply extrapolating this rate suggests that the asteroid will despin over the next 150 kyr and was spinning at its surface disruption rate 75 kyr ago, but the rotational evolution of WT24 depends on the surface's thermal properties and probably is more complex than a simple spin-down.

Original languageEnglish (US)
Pages (from-to)614-621
Number of pages8
JournalIcarus
Volume195
Issue number2
DOIs
StatePublished - Jun 2008
Externally publishedYes

Keywords

  • Asteroids
  • composition
  • dynamics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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