The application acceptance was finished. Thank you.

1999 JU3 is a minor planet, which is a target of HAYABUSA2. HAYABUSA2 will reach 1999 JU3 in June or July 2018, and return to the Earth in 2020 with sample of 1999 JU3.

Please name 1999 JU3 according to the naming rules of minor planets. No conditions are required. Applying multiple times is also possible.

Message from the project manager of the "Hayabusa2"


August 31, 2015 at 23:59 (Japan Standard Time). (Extended from 10:00)

Asteroid naming guidelines

Asteroids can't be named just anything; the International Astronomical Union (IAU) has rules. The following are conditions stipulated by IAU for naming an asteroid.

  • 16 characters or less in length. (We are sorry that our application form cannot accept the name including any spaces or punctuation)
  • preferably one word
  • pronounceable (in some language)
  • non-offensive
  • not too similar to an existing name of a minor planet or natural planetary satellite
  • Names for persons or events known primarily for their military or political activities are acceptable only after 100 years elapsed since the person died or the event occurred.
  • Names of pet animals are discouraged.
  • Names of a purely or principally commercial nature are not allowed.
  • Names not identical with or even too similar to an existing name of a minor planet or natural planetary satellite.

Near-Earth Objects (including 1999 JU3) are to receive names from mythology, except names associated with creation or underworld themes.
However, we can accept any name suggestions not only from mythology but also others.

How to submit a name

The call for application was closed. Thank you.

How is 1999 JU3 named?

  1. The entries will be judged by a selection committee experts consisted of inside and outside JAXA. The committee will inform the selected name to the Lincoln Near Earth Asteroid Research (LINEAR) Team of the U.S., that has right to suggest the name for 1999 JU3, and the LINEAR will propose the name to the IAU.
  2. The Committee for Small-Body nomenclature of the IAU will review the name.
  3. The name will be finalized when it appears in the issue of "Minor Planet Circulars (MPCs)" published by the Minor Planet Center (MPC), a subordinate organization of the IAU. The publication timeframe is not clear at this moment, but it is expected to be sometime around the end of November 2015. For your information, the MPCs is issued monthly. Please check it on the following website.

Additional Information

Table 1. Summary of 1999 JU3 and Itokawa (which was a HAYABUSA's target)


None(Not decided yet)


Provisional Designation 1999 JU3 1998 SF36
Minor planet number 162173 25143
Dimensions About 900m (diameter) 540x270x210 (m)
Shape Almost sphere Shaped like two rocks combined. Looks like "Sea otter".
Rotation period 7h 38m 12h 8m
Geometric albedo 0.05 0.25
Spectral type C-Group S-Group
Distance from the Sun Max 1.42 au, Min 0.96 au Max 1.69 au, Min 0.95 au
Semi-major axis About 178,000,000 km About 198,000,000 km
Orbital period 1.30 year 1.52 year

* 1 au(astronomical unit) = 149,597,870,700 m, from the mean distance between the Earth and the Sun.

Animation of 1999 JU3 No.1 [mp4: 413KB]
Animation of 1999 JU3 No.2 [mp4: 401KB]
Animation of 1999 JU3 No.3 [mp4: 627KB]

Fig.2 The size comparison of 1999 JU3 and Itokawa

Fig.1 The orbit and the estimated model 1999 JU3 © JAXA

Fig.3 Provisional designation of minor planets

Fig.2 The size comparison of 1999 JU3 and Itokawa © JAXA

Fig.3 Provisional designation of minor planets

Fig.3 Provisional designation of minor planets © JAXA


Fig.4 An infrared image of 1999 JU3 taken by the Japanese Infrared Imaging Surveyor "AKARI" © JAXA / Fumihiko Usui (The University of Tokyo)