Friday 14 June 2013

Imaging near-Earth asteroid (162421) 2000 ET70.

Near-Earth asteroid (162421) 2000 ET70 is a 2.6 km rocky asteroid which crosses the Earths orbital path twice during its own 336 day orbit about the Sun. This makes it fairly dangerous from an Earth-based point of view, but also particularly suitable for detailed observation, though its low albedo (dark colouration) makes this hard to do with conventional light telescopes.

In a paper published on the online arXiv database at Cornell University Library on 29 May 2013, a team of scientists led by Shantanu Naidu of the Department of Earth and Space Sciences at the University of California, Los Angeles, present the results of a study of the asteroid made during a close approach to the Earth in February 2012 using the Arecibo S-band (2380 MHz, 13 cm) radar in Puerto Rico and the Goldstone X-band (8560 MHz, 3.5 cm) radar in California.

Naidu et al. report that (162421) 2000 ET70 is significantly elongated. The region around the north pole has two ridges that are 1-1.5 km in length and almost 100 m higher than their surroundings. These ridges enclose a concavity that seems more asymmetric than most impact craters. Along the negative x-axis a large protrusion is visible. Such a feature could arise if the asteroid were made up of multiple large components resting on each other. The asteroid a spin period of approximately 8.96 hours (538 minutes).

Radar images of (162421) 2000 ET70 Naidu et al. (2013).

Orbital diagram for (162421) 2000 ET70. JPL Small Body Database Browser.

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