3554 Amun is an M-type

M-type asteroid

M-type asteroids are asteroids of partially known composition; they are moderately bright . Some, but not all, are made of nickel-iron, either pure or mixed with small amounts of stone. These are thought to be pieces of the metallic core of differentiated asteroids that were fragmented by impacts,...

 Aten asteroid

Aten asteroid

The Aten asteroids are a group of near-Earth asteroids, named after the first of the group to be discovered . They are defined by having semi-major axes of less than one astronomical unit...

 (meaning it crosses Earth's orbit) and a Venus-crosser

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...

. It was discovered on 4 March 1986 by Carolyn  and Eugene Shoemaker at Mount Palomar Observatory. Its estimated diameter

Diameter

In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...

 is 2.5 kilometers, making it one of the smallest known M-type asteroids.

Amun was once considered metallic, based on its M-type spectrum. However, like the asteroids 22 Kalliope

22 Kalliope

22 Kalliope is a large main belt M-type asteroid discovered by J. R. Hind on November 16, 1852. It is named after Calliope, the Greek Muse of epic poetry...

 and 21 Lutetia

21 Lutetia

21 Lutetia is a large main-belt asteroid of an unusual spectral type. It measures about 100 kilometers in diameter . It was discovered in 1852 by Hermann Goldschmidt, and is named after Lutetia, the Latin name for Paris....

, the radar albedo

Radar astronomy

Radar astronomy is a technique of observing nearby astronomical objects by reflecting microwaves off target objects and analyzing the echoes. This research has been conducted for six decades. Radar astronomy differs from radio astronomy in that the latter is a passive observation and the former an...

 of the object is inconsistent with a metallic composition. In Mining the Sky

Mining the Sky: Untold Riches from the Asteroids, Comets, and Planets

Mining the Sky: Untold Riches from the Asteroids, Comets, and Planets is a book by John S. Lewis which discusses the development of interplanetary space within our solar system....

, planetary scientist John S. Lewis

John S. Lewis

John S. Lewis is a professor of planetary science at the University of Arizona’s Lunar and Planetary Laboratory. His interests in the chemistry and formation of the solar system and the economic development of space have made him a leading proponent of turning potentially hazardous near-Earth...

 calculated the value of 3554 Amun at $20 trillion dollars http://www.nss.org/resources/books/non_fiction/NF_011_miningthesky.html.

(6178) 1986 DA

(6178) 1986 DA

1986 DA is a 2.3-kilometre-diameter M-type Mars-crosser and near-Earth asteroid, notable for being significantly more radar-reflective than other asteroids...

is another M-type near-Earth asteroid with lower inclination that is actually metallic.

Amun passes closest to Venus, and in 1964, 2034, and 2103 comes within 10 Gm of it. http://chemistry.unina.it/~alvitagl/solex/

External links

• Economic value of asteroid 3554 Amun