(6178) 1986 DA

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(6178) 1986 DA
Discovery [1]
Discovered by M. Kizawa
Discovery site Shizuoka (883)
Discovery date 16 February 1986
Designations
MPC designation (6178) 1986 DA
1986 DA
Amor · NEO[1]
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 38.03 yr (13,890 days)
Aphelion 4.4650 AU
Perihelion 1.1804 AU
2.8227 AU
Eccentricity 0.5818
4.74 yr (1,732 days)
150.13°
0° 12m 28.08s / day
Inclination 4.3049°
64.654°
127.33°
Earth MOID 0.1901 AU
Jupiter MOID 0.5212 AU
Physical characteristics
Dimensions 2.3 km (dated)[1]
3.149 km[2]
3.15 km (taken)[3]
3.199±0.207 km[4]
3.50 h[5][a]
3.51 h[6]
0.0778[2]
0.15[1]
0.161±0.034[4]
B–V = 0.677[1]
U–B = 0.267[1]
M[3][7]
15.1[1][4]
15.40±0.1 (R)[a]
15.9±0.112[2][3]
16.11[6]

(6178) 1986 DA is a metallic asteroid, classified as near-Earth object of the Amor group, approximately 3 kilometers in diameter. It was discovered on 16 February 1986, by Japanese astronomer Minoru Kizawa at Shizuoka Observatory, Japan.[8]

As an eccentric Amor asteroid has an Earth minimum orbit intersection distance of 0.1901 AU (28,400,000 km) and approaches the orbit of Earth from the outside but does not cross it. It crosses however the orbit of Mars and can be classified as a Mars-crosser and also approaches the orbit of Jupiter within 0.5 AU.[1] The asteroid orbits the Sun at a distance of 1.2–4.5 AU once every 4 years and 9 months (1,732 days). Its orbit has a high eccentricity of 0.58 and an inclination of 4° with respect to the plane of the ecliptic.[1] The first precovery was taken at Siding Spring Observatory in 1977, extending the asteroid's observation arc by 9 years prior to its discovery.[8]

It 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.[citation needed] Several light-curve analysis gave it a concurring rotation period of 3.50 to 3.51 hours with a relatively high brightness amplitude between 0.03 and 0.48 in magnitude, indicating an irregular shape (U=3/3/n.a.).[5][a][6]

The metallic M-type asteroid is notable for being significantly more radar-reflective than other asteroids. 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.[7]

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid has an albedo of 0.08 and 0.16, and a diameter of 3.1 to 3.2 kilometers, respectively.[2][4] The Collaborative Asteroid Lightcurve Link selects 3.15 kilometers as best result, while the first estimate from 1994 gave a diameter of 2.3 kilometers.[1]

The asteroid 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."[9] In 2012 the estimated value of 100,000 tons of platinum was worth approximately five trillion US dollars. The delta-v for a spacecraft rendezvous with this asteroid from low earth orbit is 7.1 km/s.[10]

References[edit]

  1. ^ a b c Pravec (1999) web: rotation period 3.50 hours with a brightness amplitude of 0.3 mag. H = 15.4. No LCDB quality code assigned. No lightcurve published (note: "N"). Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (6178) and Pravec, P.; Wolf, M.; Sarounova, L. (1999)
  1. ^ a b c d e f g h i j k "JPL Small-Body Database Browser: 6178 (1986 DA)" (2015-07-28 last obs.). Jet Propulsion Laboratory. Retrieved 26 May 2016. 
  2. ^ a b c d Pravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus. 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026. Retrieved 26 May 2016. 
  3. ^ a b c "LCDB Data for (6178)". Asteroid Lightcurve Database (LCDB). Retrieved 26 May 2016. 
  4. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407free to read. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 26 May 2016. 
  5. ^ a b Zeigler, K. W. (March 1990). "Photoelectric Photometry of Asteroids 81 Terpsichore, 381 Myrrha, and 1986 DA". The Minor Planet Bulletin. 17.: 1. Bibcode:1990MPBu...17....1Z. Retrieved 26 May 2016. 
  6. ^ a b c Wisniewski, W. Z. (June 1987). "Photometry of six radar target asteroids". Icarus: 566–572. Bibcode:1987Icar...70..566W. doi:10.1016/0019-1035(87)90096-0. ISSN 0019-1035. Retrieved 26 May 2016. 
  7. ^ a b Ostro, S. J.; Rosema, K. D.; Campbell, D. B.; Chandler, J. F.; Hine, A. A.; Hudson, R. S. (June 1991). "Asteroid 1986 DA - Radar evidence for a metallic composition". Science: 1399–1404.NASA–supportedresearch.(SciHomepage). Bibcode:1991Sci...252.1399O. doi:10.1126/science.252.5011.1399. ISSN 0036-8075. Retrieved 1 February 2016. 
  8. ^ a b "6178 (1986 DA)". Minor Planet Center. Retrieved 26 May 2016. 
  9. ^ Ostro, Steven J.; Campbell, D. B.; Chandler, J. F.; Hine, A. A.; Hudson, R. S.; Rosema, K. D.; et al. (October 1991). "Asteroid 1986 DA: Radar evidence for a metallic composition". In NASA. Bibcode:1991plas.rept..174O. Retrieved 1 February 2016. 
  10. ^ "Delta-v for spacecraft rendezvous with all known near-Earth asteroids". NASA. 2006-06-01. Retrieved 8 June 2006. 

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