3 Juno
Juno seen at four wavelengths with a large crater in the dark (Hooker telescope, 2003)
|
|
| Discovery | |
|---|---|
| Discovered by | Karl Ludwig Harding |
| Discovery date | September 1, 1804 |
| Designations | |
| Pronunciation | /ˈdʒuːnoʊ/ |
|
Named after
|
Juno (Latin: Iūno) |
| none | |
| Main belt (Juno clump) | |
| Adjectives | Junonian /dʒuːˈnoʊniən/ |
| Orbital characteristics | |
| Epoch JD 2457000.5 (9 December 2014) | |
| Aphelion | 3.35293 AU (502.050 Gm) |
| Perihelion | 1.98847 AU (297.40 Gm) |
| 2.67070 AU (399.725 Gm) |
|
| Eccentricity | 0.25545 |
| 4.36463 yr (1594.18 d) |
|
|
Average orbital speed
|
17.93 km/s |
| 33.077° | |
| Inclination | 12.9817° |
| 169.8712° | |
| 248.4100° | |
| Proper orbital elements | |
|
Proper semi-major axis
|
2.6693661 AU |
|
Proper eccentricity
|
0.2335060 |
|
Proper inclination
|
13.2515192° |
|
Proper mean motion
|
82.528181 deg / yr |
|
Proper orbital period
|
4.36215 yr (1593.274 d) |
|
Precession of perihelion
|
43.635655 arcsec / yr |
|
Precession of the ascending node
|
−61.222138 arcsec / yr |
| Physical characteristics | |
| Dimensions | (320×267×200)±6 km (233 km) |
| 216 000 km2 | |
| Volume | 8 950 000 km3 |
| Mass | 2.67 ×1019 kg |
|
Mean density
|
3.20 ± 0.56 g/cm³ |
| 0.12 m/s2 | |
| 0.18 km/s | |
| 7.21 hr (0.3004 d) | |
|
Equatorial rotation velocity
|
31.75 m/s |
| Albedo | 0.238 (geometric) |
| Temperature | ~163 K max: 301 K (+28°C) |
|
Spectral type
|
S-type asteroid |
| 7.4 to 11.55 | |
| 5.33 | |
| 0.30" to 0.07" | |
Juno, minor-planet designation 3 Juno in the Minor Planet Center catalogue system, is an asteroid in the asteroid belt. Juno was the third asteroid discovered, on 1 September 1804 by German astronomer Karl L. Harding. It is the 11th-largest asteroid, and one of the two largest stony (S-type) asteroids, along with 15 Eunomia. It is estimated to contain 1% of the total mass of the asteroid belt.
Juno was discovered in 1804 by Karl Ludwig Harding. It was the third asteroid found, but was initially considered to be a planet; it was reclassified as an asteroid and minor planet during the 1850s.
3 Juno is named after the mythological Juno, the highest Roman goddess. The adjectival form is Junonian (jūnōnius).
With two exceptions, 'Juno' is the international name, subject to local variation: Italian Giunone, French Junon, Russian Yunona, etc. Its planetary symbol is ③. An older symbol, still occasionally seen, is ⚵ (
).
Juno is one of the larger asteroids, perhaps tenth by size and containing approximately 1% the mass of the entire asteroid belt. It is the second-most-massive S-type asteroid after 15 Eunomia. Even so, Juno has only 3% the mass of Ceres.
The orbital period of 3 Juno is 4.36578 years.
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Wikipedia