3 Juno
A newer version of this article is available: see 3 Juno at Schools Wikipedia
| Orbital characteristics | |
|---|---|
| Orbit type | Main belt |
| Semimajor axis | 2.669 AU |
| Eccentricity | 0.2579 |
| Orbital period | 4.36 years |
| Inclination | 12.97° |
| Physical characteristics | |
| Diameter | 240 km |
| Mass | 2.0×1019 kg |
| Density | ? g/cm3 |
| Rotation period | 7h 12m |
| Spectral class | S |
| Albedo | 0.16 |
| History | |
| Discoverer | K. Harding, 1804 |
3 Juno was the third asteroid to be discovered, in 1804 by German astronomer Karl L. Harding.
Juno measures 117km in diameter. It is an S-type asteroid, meaning that it is highly reflective and composed of nickel-iron mixed with iron- and magnesium-silicates.
Juno was recently imaged by the Hooker telescope at Mount Wilson Observatory, using adaptive optics. The study revealed that Juno has had a 100-kilometre crater blasted out of it by an ancient impact, which makes the asteroid look as though a 'bite' has been taken out of it.