6 Hebe
Hebe /ˈhiːbiː/ (minor planet designation: 6 Hebe) is a large main-belt asteroid, containing around 0.5% of the mass of the belt. However, due to its apparently high bulk density (greater than that of the Moon), Hebe does not rank among the top twenty asteroids by volume. This high bulk density suggests an extremely solid body that has not been impacted by collisions, which is not typical of asteroids of its size – they tend to be loosely-bound rubble piles.
Hebe imaged by the European Southern Observatory's Very Large Telescope | |
| Discovery | |
|---|---|
| Discovered by | Karl Ludwig Hencke |
| Discovery date | 1 July 1847 |
| Designations | |
| (6) Hebe | |
| Pronunciation | /ˈhiːbiː/ |
Named after | Hēbē |
| A847 NA; 1847 JB | |
| Main belt | |
| Adjectives | Hebean /hiːˈbiːən/ |
| Symbol | (historical) |
| Orbital characteristics | |
| Epoch 13 September 2023 (JD 2453300.5) | |
| Aphelion | 2.92 AU (437 million km) |
| Perihelion | 1.93 AU (289 million km) |
| 2.43 AU (364 million km) | |
| Eccentricity | 0.2027 |
| 3.78 yr (1379.85 d) | |
Average orbital speed | 18.93 km/s |
| 144.0° | |
| Inclination | 14.736° |
| 138.63° | |
| 10 March 2022 | |
| 239.59° | |
| Earth MOID | 0.97 AU (145 million km) |
| Proper orbital elements | |
Proper semi-major axis | 2.4252710 AU |
Proper eccentricity | 0.1584864 |
Proper inclination | 14.3511092° |
Proper mean motion | 95.303184 deg / yr |
Proper orbital period | 3.77742 yr (1379.702 d) |
Precession of perihelion | 31.568209 arcsec / yr |
Precession of the ascending node | −41.829042 arcsec / yr |
| Physical characteristics | |
| Dimensions | c/a = 0.75±0.04 205 km × 185 km × 170 km |
Mean diameter | 195±3 km 186 km |
| Mass | (1.24±0.24)×1019 kg (1.27±0.13)×1019 kg |
Mean density | 3.18±0.64 g/cm3 3.77±0.43 g/cm3 |
Equatorial surface gravity | ~0.087 m/s2 |
Equatorial escape velocity | ~0.13 km/s (468 km/h) |
| 0.3031 d | |
Equatorial rotation velocity | 22.4 m/s |
| 0.268 0.268 | |
| Temperature | ~170 K max: ~269 K (−4°C) |
| S | |
| 7.5 to 11.50 | |
| 5.61 | |
| 0.26" to 0.065" | |
In brightness, Hebe is the fifth-brightest object in the asteroid belt after Vesta, Ceres, Iris, and Pallas. It has a mean opposition magnitude of +8.3, about equal to the mean brightness of Saturn's moon Titan, and can reach +7.5 at an opposition near perihelion.
Hebe may be the parent body of the H chondrite meteorites, which account for about 40% of all meteorites striking Earth.