89 Julia
Julia (minor planet designation: 89 Julia) is a large main-belt asteroid that was discovered by French astronomer Édouard Stephan on August 6, 1866. This was first of his two asteroid discoveries; the other was 91 Aegina. 89 Julia is believed to be named after Saint Julia of Corsica. A stellar occultation by Julia was observed on December 20, 1985.
VLT-SPHERE image of Julia. The large crater Nonza, half the diameter of the asteroid, is centered on the upper left quadrant. | |
| Discovery | |
|---|---|
| Discovered by | Édouard Stephan |
| Discovery date | 6 August 1866 |
| Designations | |
MPC designation | (89) Julia |
| Pronunciation | /ˈdʒuːliə/ |
Named after | Julia of Corsica |
Minor planet category | Main belt |
| Adjectives | Julian /ˈdʒuːliən/ |
| Orbital characteristics | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 149.68 yr (54672 d) |
| Aphelion | 3.0202 AU (451.82 Gm) |
| Perihelion | 2.08017 AU (311.189 Gm) |
Semi-major axis | 2.55016 AU (381.499 Gm) |
| Eccentricity | 0.18430 |
Orbital period (sidereal) | 4.07 yr (1487.5 d) |
Mean anomaly | 255.367° |
Mean motion | 0° 14m 31.272s / day |
| Inclination | 16.128° |
Longitude of ascending node | 311.563° |
| 45.461° | |
| Physical characteristics | |
| Dimensions | c/a = 0.70±0.03 (89±2)×(80±1)×(62±3) km |
Mean diameter | 140±3 km 151±3 km 148±8 km |
| Mass | (4.3±3.2)×1018 kg (4.3±3.6)×1018 kg (6.7±1.8)×1018 kg |
Mean density | 3.0±2.2 g/cm3 3.0±2.6 g/cm3 4.0±1.3 g/cm3 |
Synodic rotation period | 11.388336±0.000001 h (0.4745 day) |
| 0.216 (calculated) 0.1764±0.007 0.176 | |
| S | |
| 8.74 to 12.61 | |
| 6.60 | |
| 0.18" to 0.052" | |
The spectrum of 89 Julia shows the signature of silicate rich minerals with possible indications of an abundant calcic clinopyroxene component. It is classified as an S-type asteroid. The asteroid has an estimated diameter of 151.4±3.1 km. Photometry from the Oakley Observatory during 2006 produced a lightcurve that indicated a sidereal rotation period of 11.38±0.01 with an amplitude of 0.20±0.02 in magnitude.