(21047) Hodierna Outer Main-belt Asteroid
Discovered on 22 September 1990 by E. W. Elst at La Silla.
Giovanni Battista Hodierna (1597-1660) was a catholic priest who taught mathematics and astronomy in Ragusa, Sicily. An enthusiastic follower of Galileo, he observed the rings of Saturn and the eclipses of Jupiter's satellites. His best-known work was Medicaeorum Ephemerides.Naming citation (20040928/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Hodierna is today
Seen from above the solar system on 2026-10-14: Hodierna is 4.59 au from the Sun and 5.54 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 21047 |
| Provisional designation | 1990 SE5 |
| Orbit class | Outer Main-belt Asteroid |
| Diameter | 16.0 km (#2,884 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.0520 |
| Absolute magnitude (H) | 13.07 |
| Orbital period | 7.91 years |
| Semi-major axis | 3.97 au |
| Perihelion – aphelion | 3.27 – 4.67 au |
| Eccentricity | 0.177 |
| Inclination | 4.50° |
| Closest distance between its orbit and Earth's (MOID) | 2.26 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.
Also named after someone called Giovanni
- (6509) Giovannipratesi
- (6852) Nannibignami
- (7317) Cabot
- (7328) Casanova
- (8123) Canaletto
- (9878) Sostero
- (10928) Caprara
- (12433) Barbieri
- (12812) Cioni
- (15036) Giovannianselmi
- (15950) Dallago
- (16682) Donati
All asteroids named after someone called Giovanni
Also discovered on 22 September 1990
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- (6012) Williammurdoch
- (6268) Versailles
- (6605) Carmontelle
- (7412) Linnaeus
- (7578) Georgbohm
- (7649) Bougainville
- (7871) Tunder
- (9949) Brontosaurus
- (10088) Digne
- (10089) Turgot
- (10316) Williamturner