5 Astraea
Astraea (/æˈstriːə/) (minor planet designation: 5 Astraea) is an asteroid in the asteroid belt. Its surface is highly reflective and its composition is probably a mixture of nickel–iron with silicates of magnesium and iron. It is an S-type asteroid in the Tholen classification system.
Lightcurve-based 3D-model of Astraea | |
| Discovery | |
|---|---|
| Discovered by | K. L. Hencke |
| Discovery site | Driesen Obs. |
| Discovery date | 8 December 1845 |
| Designations | |
| (5) Astraea | |
| Pronunciation | /æˈstriːə/ |
Named after | Astraea (Greek goddess) |
| 1969 SE | |
| main-belt · (middle) Astraea | |
| Adjectives | Astraean |
| Symbol | (historical astronomical), (modern astrological) |
| Orbital characteristics | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 171.93 yr (62,799 d) |
| Aphelion | 3.0659 AU |
| Perihelion | 2.0810 AU |
| 2.5735 AU | |
| Eccentricity | 0.1914 |
| 4.13 yr (1,508 d) | |
| 186.83° | |
| 0° 14m 19.32s / day | |
| Inclination | 5.3677° |
| 141.58° | |
| 358.75° | |
| Proper orbital elements | |
Proper semi-major axis | 2.5761849 AU |
Proper eccentricity | 0.1980486 |
Proper inclination | 4.5118628° |
Proper mean motion | 87.046396 deg / yr |
Proper orbital period | 4.13573 yr (1510.574 d) |
Precession of perihelion | 52.210903 arcsec / yr |
Precession of the ascending node | −57.357951 arcsec / yr |
| Physical characteristics | |
| Dimensions | 167 km × 123 km × 82 km |
Mean diameter | 119 km |
| 48 300 km2 | |
| Volume | 882 000 km3 |
| Mass | 2.9×1018 kg (assumed) |
Mean density | ~3.3 g/cm3 |
| 0.700 03 d (16.801 h) | |
Equatorial rotation velocity | 6.44 m/s |
| 0.227 | |
| S | |
| 8.74 to 12.89 | |
| 6.85 | |
| 0.15" to 0.041" | |
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