|Discovered by||Karl Ludwig Hencke|
|Discovery date||1 July 1847|
|Epoch 26 November 2005 (JD 2453700.5)|
|Aphelion||2.914 AU (435.996 Gm)|
|Perihelion||1.937 AU (289.705 Gm)|
|2.426 AU (362.851 Gm)|
|3.78 a (1379.756 d)|
Average orbital speed
|Proper orbital elements|
Proper semi-major axis
Proper mean motion
|95.303184 deg / yr|
Proper orbital period
Precession of perihelion
|31.568209 arcsec / yr|
Precession of the ascending node
|−41.829042 arcsec / yr|
|Dimensions||205 km × 185 km × 170 km|
|109 000 km2|
|Volume||3 380 000 km3|
Equatorial surface gravity
Equatorial escape velocity
|~0.13 km/s (468 km/h)|
Equatorial rotation velocity
|Temperature||~170 K |
max: ~269 K (−4°C)
|7.5 to 11.50|
|0.26" to 0.065"|
Hebe // (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 or even Mars), 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.
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 Titan, and can reach +7.5 at an opposition near perihelion.
Hebe was discovered on 1 July 1847 by Karl Ludwig Hencke, the sixth asteroid discovered. It was the second and final asteroid discovery by Hencke, after 5 Astraea. The name Hebe, goddess of youth, was proposed by Carl Friedrich Gauss at Hencke's request. Gauss chose a wineglass as its symbol.
Hebe was once thought to be the probable parent body of the H chondrite meteorites and the IIE iron meteorites. This would imply that it is the source of about 40% of all meteorites striking Earth. Evidence for this connection includes the following:
However, observations by the VLT in 2017 indicate that the depressions cause by impacts on 6 Hebe are only 20% the volume of the nearby H-chondrite asteroid families, suggesting the Hebe is not the most likely or primary source of H-chondrite meteorites.
Lightcurve analysis suggests that Hebe has a rather angular shape, which may be due to several large impact craters. Hebe rotates in a prograde direction, with the north pole pointing towards ecliptic coordinates (β, λ) = (45°, 339°) with a 10° uncertainty. This gives an axial tilt of 42°.
It has a bright surface and, if its identification as the parent body of the H chondrites is correct, a surface composition of silicate chondritic rocks mixed with pieces of iron–nickel. A likely scenario for the formation of the surface metal is as follows:
As a result of the aforementioned 1977 occultation, a small moon around Hebe was reported by Paul D. Maley. It was nicknamed "Jebe" (see heebie-jeebies). This was the first modern-day suggestion that asteroids have satellites. It was 17 years later when the first asteroid moon was formally discovered (Dactyl, the satellite of 243 Ida). The discovery of Hebe's moon was never confirmed.
Hofrath Gauß gab auf Hencke's Ansuchen diesem neuen Planetoiden den Namen Hebe mit dem Zeichen (ein Weinglas).