19 Fortuna
| Discovery | |
|---|---|
| Discovered by | John Russell Hind |
| Discovery date | 22 August 1852 |
| Designations | |
| (19) Fortuna | |
| Pronunciation | /fɔːrˈtjuːnə/ |
Named after | Fortūna |
| A902 UG | |
| Main belt | |
| Adjectives | Fortunian /fɔːrˈtjuːniən/ |
| Symbol | (historical) |
| Orbital characteristics | |
| Epoch 17.0 October 2024 (JD 2460600.5) | |
| Aphelion | 2.831 AU (423.443 Gm) |
| Perihelion | 2.052 AU (307.028 Gm) |
| 2.441 AU (365.235 Gm) | |
| Eccentricity | 0.159 |
| 3.81 a (1393.378 d) | |
Average orbital speed | 18.94 km/s |
| 268.398° | |
| Inclination | 1.573° |
| 211.379° | |
| 182.091° | |
| Earth MOID | 1.06316 AU |
| Jupiter MOID | 2.60305 AU |
| TJupiter | 3.483 |
| Physical characteristics | |
| Dimensions | (225 × 205 × 195) ± 12 km (242 × 203 × 192) ± 10 km |
| 211±2 km 225 km | |
| Flattening | 0.21 |
| Mass | (8.8±1.4)×1018 kg 12.7×1018 kg |
Mean density | 1.80±0.29 g/cm3 2.70±0.48 g/cm3 |
Equatorial surface gravity | ~0.0629 m/s² |
Equatorial escape velocity | ~0.1190 km/s |
| 7.4432 h (0.3101 d) 7.443224±0.000001 h | |
| 29° | |
Pole ecliptic latitude | 60°±3° |
Pole ecliptic longitude | 103°±3° |
| 0.056 0.037 | |
| Temperature | ~180 K |
| G | |
| 8.88 to 12.95 | |
| 7.49 7.13 | |
| 0.25" to 0.072" | |
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19 Fortuna is one of the largest main-belt asteroids. It has a composition similar to 1 Ceres: a darkly colored surface that is heavily space-weathered with the composition of primitive organic compounds, including tholins.
Fortuna is 225 km in diameter and has one of the darkest known geometric albedos for an asteroid over 150 km in diameter. Its albedo has been measured at 0.028 and 0.037. The spectra of the asteroid displays evidence of aqueous alteration.
The Hubble Space Telescope observed Fortuna in 1993. It was resolved with an apparent diameter of 0.20 arcseconds (4.5 pixels in the Planetary Camera) and its shape was found to be nearly spherical. Satellites were searched for but none were detected.
Stellar occultations by Fortuna have been observed several times. Fortuna has been studied by radar.
It was discovered by J. R. Hind on 22 August 1852, and named after Fortuna, the Roman goddess of luck. Its historical symbol was a star over Fortune's wheel; it is in the pipeline for Unicode 17.0 as U+1CECC ().
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Fortuna has been perturbed by the 80 km 135 Hertha and was initially estimated by Baer to have a mass of 1.08×1019 kg. A more recent estimate by Baer suggests it has a mass of 1.27×1019 kg.
On 21 December 2012, Fortuna (~200 km) harmlessly passed within 6.5 Gm of asteroid 687 Tinette.