Radar imaging and physical characterization of near-Earth Asteroid (162421) 2000 ET70

被引：13

作者：

Naidu, Shantanu P. ^{[1
]}

Margot, Jean-Luc ^{[1
,2
]}

Busch, Michael W. ^{[1
]}

Taylor, Patrick A. ^{[3
]}

Nolan, Michael C. ^{[3
]}

Brozovic, Marina ^{[4
]}

Benner, Lance A. M. ^{[4
]}

Giorgini, Jon D. ^{[4
]}

Magri, Christopher ^{[5
]}

机构：

[1] Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA

[2] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA

[3] Arecibo Observ, Arecibo, PR 00612 USA

[4] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA

[5] Univ Maine, Farmington, ME 04938 USA

来源：

ICARUS | 2013年 / 226卷 / 01期

基金：

美国国家航空航天局; 美国国家科学基金会;

关键词：

Near-Earth objects; Asteroids; Radar observations; Orbit determination; OPTICAL OBSERVATIONS; 1999; KW4; BINARY; POPULATION; IMAGES; MODEL; EVOLUTION; GOLEVKA; ORIGIN; SHAPE;

D O I：

10.1016/j.icarus.2013.05.025

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We observed near-Earth Asteroid (162421) 2000 ET70 using the Arecibo and Goldstone radar systems over a period of 12 days during its close approach to the Earth in February 2012. We obtained continuous wave spectra and range-Doppler images with range resolutions as fine as 15 m. Inversion of the radar images yields a detailed shape model with an effective spatial resolution of 100 m. The asteroid has overall dimensions of 2.6 km x 2.2 km x 2.1 km (5% uncertainties) and a surface rich with kilometer-scale ridges and concavities. This size, combined with absolute magnitude measurements, implies an extremely low albedo (similar to 2%). It is a principal axis rotator and spins in a retrograde manner with a sidereal spin period of 8.96 +/- 0.01 h. In terms of gravitational slopes evaluated at scales of 100 m, the surface seems mostly relaxed with over 99% of the surface having slopes less than 30 degrees, but there are some outcrops at the north pole that may have steeper slopes. Our precise measurements of the range and velocity of the asteroid, combined with optical astrometry, enables reliable trajectory predictions for this potentially hazardous asteroid in the interval 460-2813. (C) 2013 Elsevier Inc. All rights reserved.

引用

页码：323 / 335

页数：13

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