小惑星6番 ヘーベ (6)Hebe
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(6) Hebe
Hebe (/'hi:bi:/ HEE-bee; minor planet designation: 6 Hebe) is a large main-belt asteroid, containing around half a percent 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,[8] and can reach +7.5 at an opposition near perihelion. Hebe is probably the parent body of the H chondrite meteorites, which account for about 40% of all meteorites striking Earth. |
2019年01月16日 8.8等