(6178) 1986 DA
|Discovered by||Minoru Kizawa|
|Discovery date||February 16, 1986|
|Minor planet category||Amor asteroid|
|Epoch July 14, 2004 (JD 2453200.5)|
|Aphelion||666.686 Gm (4.457 AU)|
|Perihelion||173.713 Gm (1.161 AU)|
|Semi-major axis||420.199 Gm (2.809 AU)|
|Orbital period||1719.466 d (4.71 a)|
|Average orbital speed||17.77 km/s|
|Longitude of ascending node||64.795°|
|Argument of perihelion||127.171°|
|Dimensions||2.3 km 1|
|Mean density||5 g/cm³|
|Equatorial surface gravity||? m/s²|
|Escape velocity||? km/s|
|Rotation period||0.149 d |
|Spectral type||M-type asteroid|
|Absolute magnitude (H)||15.1|
(6178) 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. It is an Amor asteroid, which means it approaches the orbit of Earth from the outside but does not cross it.
Radar measurements suggest it is composed of nickel and iron and that it was derived from the center of a much larger object that experienced melting and differentiation. The observed radar albedo was 0.58 and the optical albedo was 0.14.
This asteroid was most probably formed from a larger body through a catastrophic collision with another object. Radar measurements of this body indicate that the surface is relatively smooth on scales of less than a meter, but it is highly irregular on scales of 10–100 meters.
1986 DA reached perihelion in its orbit on March 6, 2005.
Asteroid 1986 DA achieved its most notable recognition when scientists revealed that it contained over "10,000 tons of gold and 100,000 tons of platinum", or an approximate value at the time of its discovery of "$90 billion for the gold and a cool trillion dollars for the platinum, plus loose change for the asteroid's 10 billion tons of iron and a billion tons of nickel."
In 2012 the estimated value of 100,000 tons of platinum was worth approximately five trillion US dollars.
- S. J. OSTRO, D. B. CAMPBELL, J. F. CHANDLER, A. A. HINE, R. S. HUDSON, K. D. ROSEMA, and I. I. SHAPIRO (7 June 1991). "Asteroid 1986 DA: Radar Evidence for a Metallic Composition". Science 252 (5011): 1399–1404. Bibcode:1991Sci...252.1399O. doi:10.1126/science.252.5011.1399. PMID 17772910.
- "Delta-v for spacecraft rendezvous with all known near-Earth asteroids". NASA. 2006-06-01. Retrieved 2006-06-08.
- staff, editorial (1991-06-08). "Gems In Space -- Undreamed Treasures In A Passing Nugget". The Seattle Times. Archived from the original on 2009-04-18. Retrieved 2009-04-05.
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