41 Daphne
Main-belt asteroid
From Wikipedia, the free encyclopedia
41 Daphne is a large asteroid from the asteroid belt.[1] It is a dark-surfaced body 174 km in diameter is probably composed of primitive carbonaceous chondrites. The spectra of the asteroid displays evidence of aqueous alteration.[8] It was discovered by H. Goldschmidt on May 22, 1856, and named after Daphne, the nymph in Greek mythology who was turned into a laurel tree. Incorrect orbital calculations initially resulted in 56 Melete being mistaken for a second sighting of Daphne. Daphne was not sighted again until August 31, 1862.[9]
 | |
| Discovery[1] | |
|---|---|
| Discovered by | H. Goldschmidt |
| Discovery date | May 22, 1856 |
| Designations | |
| (41) Daphne | |
| Pronunciation | /ˈdæfni/[2] |
Named after | Daphne |
| 1949 TG | |
| Main belt | |
| Adjectives | Daphnean /ˈdæfniən/[3] |
| Orbital characteristics[1] | |
| Epoch 31 December 2006 (JD 2454100.5) | |
| Aphelion | 3.517 AU (526.144 million km) |
| Perihelion | 2.014 AU (301.220 million km) |
| 2.765 AU (413.682 million km) | |
| Eccentricity | 0.272 |
| 4.60 a (1,679.618 d) | |
| 247.500° | |
| Inclination | 15.765° |
| 178.159° | |
| 46.239° | |
| Known satellites | Peneius /pɛˈniːəs/ (S/2008 (41) 1) |
| Physical characteristics | |
| Dimensions | 213×160 km[4] 239x183x153 km[5] |
| 187±13 km[6] 205.495±1.881[1] 189 km[7] | |
| Flattening | 0.35[a] |
| Mass | (6.1±0.9)×1018 kg[6] ≈ 6.8×1018 kg[b] |
Mean density | 1.78±0.45 g/cm3[6] ≈ 1.95 g/cm3[5] |
| 5.988 hr[1] | |
| 0.052 (calculated)[6] 0.059±0.007[1] | |
| C[1] | |
| 7.61[1] | |
The orbit of 41 Daphne places it in a 9:22 mean motion resonance with the planet Mars. The computed Lyapunov time for this asteroid is 14,000 years, indicating that it occupies a chaotic orbit that will change randomly over time because of gravitational perturbations of the planets.[10]
In 1999, Daphne occulted three stars, and on July 2, 1999, produced eleven chords indicating an ellipsoid of 213×160 km.[4] Daphnean lightcurves also suggest that the asteroid is irregular in shape. Daphne was observed by Arecibo radar in April 2008.[11][12] Based upon radar data, the near surface solid density of the asteroid is 2.4+0.7
−0.5 g cm−3.[13]
Satellite
 Daphne and Peneius as seen by the W.M. Keck II telescope in 2008 | |
| Designations | |
|---|---|
| (41) Daphne I | |
| Pronunciation | /pɛˈniːəs/ |
| S/2008 (41) 1 | |
| Adjectives | Peneian /pɛˈniːən/ |
| Orbital characteristics | |
| Inclination | ° |
41 Daphne has at least one satellite, named Peneius (provisionally S/2008 (41) 1).[14][15] It was identified on March 28, 2008, and has a projected separation of 443 km, an orbital period of approximately 1.1 days,[5] and an estimated diameter of less than 2 km. If these preliminary observations hold up, this binary system has the most extreme size ratio known.[16] In Greek myth, Pēneios is the god of the river of that name, and father of Daphne.
Notes
- Using the formula for volume of an ellipsoid (m = v × d), 239 × 183 × 153 km times a density of 1.95 g/cm3 yields a mass of 6.8×1018 kg
