69230 Hermes

[5] Hermes was discovered by German astronomer Karl Reinmuth in images taken at Heidelberg Observatory on 28 October 1937.

[18] On 15 October 2003, Brian A. Skiff of the LONEOS project made an asteroid observation that, when the orbit was calculated backwards in time (by Timothy B. Spahr, Steven Chesley and Paul Chodas), turned out to be a rediscovery of Hermes.

Additional precovery observations were published by the Minor Planet Center, the earliest being found in images taken serendipitously by the MPG/ESO 2.2-m La Silla telescope on 16 September 2000.

Frequent close approaches to both Earth and Venus make it unusually challenging to forecast its orbit more than a century in advance, though there is no impact risk within that timeframe.

[20] The asteroid has an Earth minimum orbital intersection distance of 0.0041 AU (610,000 km) which translates into 1.6 LD.

[21] In retrospect it turned out that Hermes came even closer to the Earth in 1942 than in 1937, within 1.7 lunar distances; the second pass was unobserved at the height of the Second World War.

Lightcurve analysis gave a well-defined rotation period between 13.892 and 13.894 hours with a brightness variation between and 0.06 and 0.08 magnitude, which indicates that the body has a nearly spherical shape (U=3/3/3).

[15][11][12] [a] Radar observations led by Jean-Luc Margot at Arecibo Observatory and Goldstone in October and November 2003 showed Hermes to be a binary asteroid.

Animation of 69230 Hermes's orbit - close approach in 1942
Sun · Earth · 69230 Hermes
Arecibo radar image from 19 October 2003, showing the relative motion of the components. [ 9 ]