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.
See also Asteroid 2013 LR6 passes between the Earth and the Moon, The Arietid Meteors, The Main-Belt Comet P/2012 T1 (PANSTARRS), Asteroid 1998 QE2 to pass Earth at about 5 800 000 km on Friday and Second meteorite from New Haven County, Connecticut.
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