306 Unitas
Unitas (minor planet designation: 306 Unitas) is a typical main belt asteroid that was discovered by Elia Millosevich on 1 March 1891 in Rome. The asteroid was named by the director of the Modena Observatory in honor of the Italian astronomer Angelo Secchi (author of Unità delle forze fisiche) and the unification of Italy. It is classified as an S-type asteroid.
A three-dimensional model of 306 Unitas based on its light curve | |
| Discovery | |
|---|---|
| Discovered by | Elia Millosevich |
| Discovery date | 1 March 1891 |
| Designations | |
MPC designation | (306) Unitas |
| Pronunciation | /ˈjuːnɪtæs/ |
Alternative designations | A891 EA |
Minor planet category | Main belt |
| Orbital characteristics | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 124.78 yr (45575 d) |
| Aphelion | 2.71480 AU (406.128 Gm) |
| Perihelion | 2.0009 AU (299.33 Gm) |
Semi-major axis | 2.35785 AU (352.729 Gm) |
| Eccentricity | 0.15139 |
Orbital period (sidereal) | 3.62 yr (1322.4 d) |
Mean anomaly | 88.9729° |
Mean motion | 0° 16m 20.014s / day |
| Inclination | 7.2779° |
Longitude of ascending node | 141.912° |
| 168.008° | |
| Physical characteristics | |
| Dimensions | 46.70±2.3 km 52.88 ± 3.48 km |
| Mass | (5.33 ± 5.77) × 1017 kg |
Synodic rotation period | 8.736 h (0.3640 d) 8.73875 h |
| 0.2112±0.023 0.211 | |
| S | |
| 8.96 | |
In the late 1990s, a network of astronomers worldwide gathered light curve data that was ultimately used to derive the spin states and shape models of 10 new asteroids, including (306) Unitas. The computed shape model for this asteroid is regular, while the light curve displays two maxima per rotation. Lightcurve data has also been recorded by observers at the Antelope Hill Observatory, which has been designated as an official observatory by the Minor Planet Center.
Measurements of the thermal inertia of 306 Unitas give an estimate range from 100 to 260 m−2 K−1 s−1/2, compared to 50 for lunar regolith and 400 for coarse sand in an atmosphere.
Although 306 Unitas has an orbit similar to the Vesta family asteroids, it was found to be an unrelated interloper on the basis of its non-matching spectral type.
- Orbir diagram of 306 Unitas