(162173) 1999 JU3

162173 Ryugu

Discovery
Discovered by	LINEAR
Discovery date	10 May 1999
Designations
Named after	Ryūgū-jō
Alternative names	1999 JU3
Minor planet category	Apollo asteroid
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc	9567 days (26.19 yr)
Aphelion	1.4158 AU (211.80 Gm)
Perihelion	0.96328 AU (144.105 Gm)
Semi-major axis	1.1895 AU (177.95 Gm)
Eccentricity	0.19021
Orbital period	1.30 yr (473.88 d)
Mean anomaly	58.18147°
Mean motion	0.759682°/day
Inclination	5.8836°
Longitude of ascending node	251.6034°
Argument of perihelion	211.4547°
Earth MOID	0.000320643 AU (47,967.5 km)
Jupiter MOID	3.70493 AU (554.250 Gm)
Physical characteristics
Dimensions	980 ± 29 m[2]
Rotation period	7.627 h (0.3178 d)
Spectral type	Cg
Absolute magnitude (H)	19.2

162173 Ryugu (provisional designation 1999 JU₃) is an Apollo asteroid. It is planned that the Japanese space probe Hayabusa 2 returns samples from this asteroid by December 2020. It is the rare spectral type Cg, having qualities of both a C-type asteroid and a G-type asteroid.

History

Discovery

Ryugu was discovered in 1999 by the LINEAR project, and was given the provisional designation 1999 JU₃.

Name

The asteroid was officially named Ryugu on 5 October 2015.^[3] Its name refers to Ryūgū-jō (Dragon's Palace), a wonderful and magical palace on the bottom of the ocean where Urashima Tarō, in a Japanese folktale, was brought by a turtle. When he returned, he brought back with him a mysterious box—much as Hayabusa 2 will bring back a capsule with samples.

See also

• List of asteroids targeted for spacecraft visitation

References

1. "JPL Small-Body Database Browser: 162173 Ryugu (1999 JU3)". Jet Propulsion Laboratory. Retrieved 26 March 2016.
2. Hasegawa, S.; et al. (2008). "Albedo, Size, and Surface Characteristics of Hayabusa-2 Sample-Return Target 162173 1999 JU3 from AKARI". Publications of the Astronomical Society of Japan 60 (SP2): S399–S405. doi:10.1093/pasj/60.sp2.s399.
3. "Name Selection of Asteroid 1999 JU3 Target of the Asteroid Explorer “Hayabusa2”" (Press release). JAXA. October 5, 2015. Retrieved 2015-10-06.

Bibliography

• Abe, M.; et al. (2008). Ground-based observational campaign for asteroid 162173 1999 JU3 (PDF). 37th COSPAR Scientific Assembly. Lunar and Planetary Science 39. p. 1594.
• Campins, H.; et al. (2009). "Spitzer observations of spacecraft target 162173 (1999 JU3)". Astronomy and Astrophysics Letters 503: L17. arXiv:0908.0796. Bibcode:2009A&A...503L..17C. doi:10.1051/0004-6361/200912374.
• Hasegawa, S.; et al. (2008). "Albedo, Size, and Surface Characteristics of Hayabusa-2 Sample-Return Target 162173 1999 JU3 from AKARI". Publications of the Astronomical Society of Japan 60 (SP2): S399–S405. doi:10.1093/pasj/60.sp2.s399.
• Vilas, F. (2008). "Spectral Characteristics of Hayabusa 2 Near-Earth Asteroid Targets 162173 1999 Ju3 and 2001 Qc34". Astronomical Journal 135: 1101. Bibcode:2008AJ....135.1101V. doi:10.1088/0004-6256/135/4/1101.
• "International Symposium Marco Polo and other Small Body Sample Return Missions: Programme and Presentations". European Space Agency. 18–20 May 2009.

External links

• 162173 Ryugu at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters