162173 Ryugu

"Ryugu" redirects here. For the Japanese folklore palace, see Ryūgū-jō.

162173 Ryugu
Color image of Ryugu taken by Hayabusa2, 2018
Discovery[1]
Discovered byLINEAR
Discovery siteLincoln Lab's ETS
Discovery date10 May 1999
Designations
(162173) Ryugu
Pronunciation/riˈuːɡuː/
Japanese: [ɾjɯːɡɯː]
Named after
Ryūgū[1]
("Dragon palace")
1999 JU3
Apollo · NEO · PHA[1][2]
Orbital characteristics[2]
Epoch 12 December 2011 (JD 2455907.5)
Uncertainty parameter 0
Observation arc30.32 yr (11,075 d)
Aphelion1.4159 AU
Perihelion0.9633 AU
1.1896 AU
Eccentricity0.1902
1.30 yr (474 d)
3.9832°
0° 45m 34.56s / day
Inclination5.8837°
251.62°
211.43°
Earth MOID0.0006 AU (0.2337 LD)
Physical characteristics
Dimensions1004 m × 876 m[3]
448±2 m[3]
Equatorial radius
502±2 m[3]
Polar radius
438±2 m[3]
Volume0.377±0.005 km3[3]
Mass(4.50±0.06)×1011 kg[3][4]
Mean density
1.19±0.03 g cm−3[3]
Equatorial surface gravity
1/80,000 g[4]
7.63262±0.00002 h[3]
171.64°±0.03°[3]
North pole right ascension
+96.40°±0.03°[3]
North pole declination
−66.40°±0.03°[3]
0.037±0.002[5]
0.042±0.003[6]
0.047±0.003[7]
0.063±0.020[8]
0.07±0.01[9]
0.078±0.013[10]
SMASS = Cg[2] · C[7] · Cb[11]
18.69±0.07 (R)[10]
18.82[8]
19.2[5]
19.25±0.03[7]
19.3[1][2]

162173 Ryugu (provisional designation 1999 JU3) is a near-Earth object and a potentially hazardous asteroid of the Apollo group. It measures approximately 900 metres (3,000 ft) in diameter and is a dark object of the rare spectral type Cb,[11] with qualities of both a C-type asteroid and a B-type asteroid. In June 2018, the Japanese spacecraft Hayabusa2 arrived at the asteroid.[12] After making measurements and taking samples, Hayabusa2 left Ryugu for Earth in November 2019[13][14] and returned the sample capsule to Earth on 5 December 2020.[14] The samples showed the presence of organic compounds, such as uracil (one of the four components in RNA) and vitamin B3.

  1. ^ a b c d Cite error: The named reference MPC-object was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference jpldata was invoked but never defined (see the help page).
  3. ^ a b c d e f g h i j k Cite error: The named reference Watanabe et al. 2019 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference SpaceFlightNow was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Abe-2008 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Liang-liang-2014 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Muller-2017a was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Hasegawa-2008 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Campins-2009b was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Kim-2013 was invoked but never defined (see the help page).
  11. ^ a b Sugita, S.; Honda, R.; Morota, T.; Kameda, S.; Sawada, H.; Tatsumi, E.; Honda, C.; Yokota, Y.; Yamada, M.; Kouyama, T.; Sakatani, N. (July 2019). "Ryugu's Parent-Body Processes Estimated from Hayabusa2 Multi-Band Optical Observations". 82nd Annual Meeting of The Meteoritical Society, held 7-12 July, 2019 in Sapporo, Japan. LPI Contribution. Vol. 2157. p. 6366. Bibcode:2019LPICo2157.6366S. ISSN 0161-5297.{{cite book}}: CS1 maint: date and year (link)
  12. ^ Chang, Kenneth; Stirone, Shannon (19 March 2019). "The Asteroid Was Shooting Rocks Into Space. 'Were We Safe in Orbit?'". The New York Times. Retrieved 21 March 2019. NASA's Osiris-Rex and Japan's Hayabusa2 spacecraft reached the space rocks they are surveying last year, and scientists from both teams announced early findings on Tuesday.
  13. ^ Stephen Clark (13 November 2019). "Japanese sample return craft departs asteroid, heads for Earth"./
  14. ^ a b Cite error: The named reference NYT-20201205 was invoked but never defined (see the help page).