69230 Hermes
Encyclopedia
69230 Hermes is an Apollo
, Mars-
and Venus-crosser asteroid
that passed Earth at about twice the distance of the Moon on October 30, 1937. It is named after the Greek god Hermes
.
At the time, this was the closest known approach of an asteroid
to the Earth. Not until 1989 was a closer approach (by 4581 Asclepius
) observed. At closest approach, Hermes was moving 5° per hour across the sky and reached 8th magnitude.
It was discovered by Karl Reinmuth in images taken on October 28, 1937. Only four days of observations could be made before Hermes became too faint to be seen in the telescopes of the day. This was not enough to calculate an orbit, and Hermes was "lost" (see lost asteroids
). It thus did not receive a number, but Reinmuth nevertheless named it after the Greek god Hermes
. It was the only unnumbered but named asteroid, having only the provisional designation 1937 UB.
On October 15, 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. The orbit is now well known, and Hermes has been assigned sequential number 69230. In retrospect it turned out that Hermes came even closer to the Earth in 1942 than in 1937, within 1.7 Moon distances, without being observed. On 1937-Oct-30 it passed 0.00494 AU from the Earth and on 1942-Apr-26 it passed 0.0042415 AU from Earth.
Hermes is an S-type asteroid
, a classification first reported by Andy Rivkin and Richard Binzel. Radar observations led by Jean-Luc Margot
at Arecibo Observatory
and Goldstone
in October and November 2003 showed Hermes to be a binary asteroid
. The primary and secondary components have nearly identical radii of 300–450 m (984.3–1,476.4 ft), and their orbital separation is only 1200 m.
Apollo asteroid
The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, the first asteroid of this group to be discovered by Karl Wilhelm Reinmuth...
, Mars-
Mars-crosser asteroid
A Mars-crosser is an asteroid whose orbit crosses that of Mars. The known numbered Mars-crossers are listed here. They include the two numbered Mars trojans 5261 Eureka and ....
and Venus-crosser asteroid
Venus-crosser asteroid
A Venus-crosser is an asteroid whose orbit crosses that of Venus. The known numbered Venus-crossers and outer-grazers are listed below .Venus also has a quasi-satellite, 2002 VE68...
that passed Earth at about twice the distance of the Moon on October 30, 1937. It is named after the Greek god Hermes
Hermes
Hermes is the great messenger of the gods in Greek mythology and a guide to the Underworld. Hermes was born on Mount Kyllini in Arcadia. An Olympian god, he is also the patron of boundaries and of the travelers who cross them, of shepherds and cowherds, of the cunning of thieves, of orators and...
.
At the time, this was the closest known approach of an asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
to the Earth. Not until 1989 was a closer approach (by 4581 Asclepius
4581 Asclepius
-External links:* from JPL /...
) observed. At closest approach, Hermes was moving 5° per hour across the sky and reached 8th magnitude.
It was discovered by Karl Reinmuth in images taken on October 28, 1937. Only four days of observations could be made before Hermes became too faint to be seen in the telescopes of the day. This was not enough to calculate an orbit, and Hermes was "lost" (see lost asteroids
Lost asteroids
Lost asteroids or lost planets are asteroids that observers lose track of after discovering. Many early lost asteroids were rediscovered in the 1980s and 1990s, but a number of asteroids and other types of small Solar System bodies continue to be lost...
). It thus did not receive a number, but Reinmuth nevertheless named it after the Greek god Hermes
Hermes
Hermes is the great messenger of the gods in Greek mythology and a guide to the Underworld. Hermes was born on Mount Kyllini in Arcadia. An Olympian god, he is also the patron of boundaries and of the travelers who cross them, of shepherds and cowherds, of the cunning of thieves, of orators and...
. It was the only unnumbered but named asteroid, having only the provisional designation 1937 UB.
On October 15, 2003, Brian A. Skiff
Brian A. Skiff
Brian A. Skiff is an American astronomer noted for discovering a number of comets including the periodic comets 114P/Wiseman-Skiff and 140P/Bowell-Skiff...
of the LONEOS project made an asteroid observation that, when the orbit was calculated backwards in time (by Timothy B. Spahr
Timothy B. Spahr
Timothy B. Spahr is an American astronomer.He works at the Harvard-Smithsonian Center for Astrophysics as director of the Minor Planet Center, has discovered numerous asteroids and is credited as a co-discoverer of one satellite of Jupiter and one of Saturn .He also discovered two periodic comets...
, Steven Chesley and Paul Chodas), turned out to be a rediscovery of Hermes. The orbit is now well known, and Hermes has been assigned sequential number 69230. In retrospect it turned out that Hermes came even closer to the Earth in 1942 than in 1937, within 1.7 Moon distances, without being observed. On 1937-Oct-30 it passed 0.00494 AU from the Earth and on 1942-Apr-26 it passed 0.0042415 AU from Earth.
Hermes is an S-type asteroid
S-type asteroid
S-type asteroids are of a stony composition, hence the name. Approximately 17% of asteroids are of this type, making it the second most common after the C-type.-Characteristics:...
, a classification first reported by Andy Rivkin and Richard Binzel. Radar observations led by Jean-Luc Margot
Jean-Luc Margot
Jean-Luc Margot is a Belgian-born astronomer and a Professor at UCLA. He specializes in planetary sciences. He was awarded the H. C. Urey Prize by the American Astronomical Society in 2004....
at Arecibo Observatory
Arecibo Observatory
The Arecibo Observatory is a radio telescope near the city of Arecibo in Puerto Rico. It is operated by SRI International under cooperative agreement with the National Science Foundation...
and Goldstone
Goldstone
-Places:*Goldstone, a small village in Shropshire, England*Goldstone Lake, a dry lake in the Mojave Desert of San Bernardino County, California*Goldstone Vallis, a valley on Mercury-Things:* Goldstone , a gemstone simulant...
in October and November 2003 showed Hermes to be a binary asteroid
Binary asteroid
A binary asteroid is a system of two asteroids orbiting their common center of mass, in analogy with binary stars. 243 Ida was the first binary asteroid to be identified when the Galileo spacecraft did a flyby in 1993...
. The primary and secondary components have nearly identical radii of 300–450 m (984.3–1,476.4 ft), and their orbital separation is only 1200 m.
In popular culture
- In the 1978 novel The Hermes Fall by John BaxterJohn Baxter (author)John Baxter is an Australian-born writer, journalist, and film-maker.Baxter has lived in Britain and the United States as well as in his native Sydney, but has made his home in Paris since 1989, where he is married to the film-maker Marie-Dominique Montel...
, the asteroid endangers the Earth in 1980.