162173 Ryugu
OVERVIEW
] ASTEROID162173 Ryugu is an Apollo near-Earth asteroid. Its absolute magnitude () is 19.55. It orbits the Sun at a mean distance of 1.191 . It has a mass of 4.49×10¹¹ and an effective radius of 0.45 . It is catalogued as 162173 Ryugu (1999 JU3). It was discovered in 1999.
A carbon-rich rubble pile sampled by Hayabusa2; the returned grains contain amino acids older than the Earth.
- WHAT IT IS
- Apollo near-Earth asteroid
- HOW FAR
- 1.191
- HOW BIG
- 0.45
- HOW BRIGHT IN ITSELF (H)
- ONE ORBIT TAKES
- 475
Its average distance from the Sun, not from Earth.
The radius of a ball that would look the same size — the body itself is not round.
How bright it would look from a fixed, standard distance — a measure of the object rather than of the view from here.
One trip round the Sun.
IMAGES
] 1 FRAMES- Original image taken by JAXA/ISAS, processed by User:Anonymsiy, image adjusted by User:Nrco0e
CC BY 4.0
OBSERVING
] FROM WHERE YOU AREWhat it takes to see 162173 Ryugu for yourself. Everything in this part of the page is worked out for a real horizon, a real night and the equipment you say you have.
CATALOG DATA
] 17 FIELDSThe raw catalogue values, as the source published them, with the error bars where one was published — sorted by what each set of figures is about rather than by the order they happened to be stored in.
WHAT IT IS MADE OF
What the object is in itself, rather than how it happens to look from here.
- Spectral type (SMASS II)
- Cb
- Rotation period
- 7.63262
HOW BRIGHT IT IS
What the light adds up to, measured through one filter at a time. A magnitude is a brightness on a backwards scale — the smaller the number, the brighter the object.
- Albedo
THE ORBIT
The shape of the path, where the object sits on it, and the instant those figures were true of. An orbit is a fit to observations and drifts away from the real one either side of its epoch.
- Orbital period
- 475
- Eccentricity
- Inclination
- 5.87
- Longitude of ascending node
- 251.29
- Argument of perihelion
- 211.61
- Mean anomaly
- 62.34
- Element epoch
- 2461200.5000
- Perihelion passage
- 2461118.3000
- Minimum distance from Earth's orbit
- 0.000539
- Orbit class
- APO
WHEN IT WAS FOUND
Who first saw it, from where, and by what method.
- Discovered by
- LINEAR
- Discovered from
- Socorro
- Discovered on
- 1999-05-10
- First observed
- 1986-04-14
ALSO KNOWN AS
] 3 DESIGNATIONS- Asteroid 162173
- Asteroid 162173 Ryugu (1999 JU3)
- Common name Ryugu
LOOK IT UP ELSEWHERE
] 1 SERVICEEach link carries the identifier printed beside it. Nothing on this page is a measurement of our own, so a number that disagrees with one of these is worth reporting — and a service that has never catalogued this object under this name will say so plainly.
- JPL Small-Body Database162173
The orbit these elements were taken from, with its uncertainty, its close approaches and every observation behind the fit.
CITE THIS PAGE
] DR1This page is live and its numbers move when an upstream refreshes, so the citation names the release the rows belong to rather than the day you read them. The release itself is frozen, republished as a bundle, and is what a data-availability statement should point at.
SpaceCatalog. 162173 Ryugu [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/162173-ryugu
@misc{spacecatalog_162173-ryugu,
author = {{SpaceCatalog}},
title = {{162173 Ryugu}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/162173-ryugu},
note = {Catalogue entry, data release DR1 (2026-08-21). Values from JPL Small-Body Database.}
}The values above were taken from JPL Small-Body Database — Public domain (NASA/JPL). Citing this page does not replace citing that catalogue.