41 Daphne

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Not to be confused with Daphnis (moon). ‹See Tfd›
41 Daphne
41Daphne-Keck.jpg
Daphne and satellite as seen by the W.M. Keck II telescope in 2008
Discovery[1]
Discovered by H. Goldschmidt
Discovery date May 22, 1856
Designations
Pronunciation /ˈdæfn/
Named after
Daphnē
1949 TG
Minor planet category Main belt
Adjectives Daphnean /ˈdæfnən/
Orbital characteristics[1]
Epoch December 31, 2006 (JD 2454100.5)
Aphelion 526.144 Gm (3.517 AU)
Perihelion 301.220 Gm (2.014 AU)
413.682 Gm (2.765 AU)
Eccentricity 0.272
1,679.618 d (4.60 a)
17.58 km/s
247.500°
Inclination 15.765°
178.159°
46.239°
Known satellites S/2008 (41) 1
Physical characteristics
Dimensions 174.0 ± 11.2 km (IRAS)[1]
189 km[2]
213×160 km[3]
239x183x153 km[4]
Mass ~6.8×1018 kg[5]
Mean density
~1.95 g/cm³[4]
5.9 hr[1]
Albedo 0.083[1]
Temperature ~167 K
Spectral type
C[1]
7.12[1]

41 Daphne is a large 174 km main-belt asteroid.[1] This dark-surfaced body is probably composed of primitive carbonaceous chondrites. 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.[6]

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.[7]

In 1999, Daphne occulted three stars, and on July 2, 1999 produced eleven chords indicating an ellipsoid of 213×160 km.[3] Daphnean lightcurves also suggest that the asteroid is irregular in shape. Daphne was observed by Arecibo radar in April 2008.[8][9] Based upon radar data, the near surface solid density of the asteroid is 2.4+0.7
−0.5
g cm–3.[10]

Satellite[edit]

41 Daphne has at least one satellite, named S/2008 (41) 1.[11] It was identified on March 28, 2008, and has a projected separation of 443 km, an orbital period of approximately 1.1 days,[4] 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.[12]

References[edit]

  1. ^ a b c d e f g h Yeomans, Donald K., "41 Daphne", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 2013-04-07. 
  2. ^ Matter, Alexis; Marco Delbo, Sebastiano Ligori, Nicolas Crouzet, Paolo Tanga (2011). "Determination of physical properties of the asteroid (41) Daphne from interferometric observations in the thermal infrared". Icarus 215 (1): 47–56. arXiv:1108.2616. Bibcode:2011Icar..215...47M. doi:10.1016/j.icarus.2011.07.012. 
  3. ^ a b "1999 European Asteroidal Occultation Results". euraster.net (a website for Asteroidal Occultation Observers in Europe). 2009-02-09. Retrieved 2008-12-01.  (1999-Jul-02 Chords)
  4. ^ a b c Conrad, Al; Carry, B.; Drummond, J. D.; Merline, W. J.; Dumas, C.; Owen, W. M.; Chapman, C. R.; Tamblyn, P. M.; Goodrich, R. W.; Campbell, R. D. (2008). "Shape and Size of Asteroid (41) Daphne from AO Imaging". American Astronomical Society 40 (28.12): 438. Bibcode:2008DPS....40.2812C. 
  5. ^ Using the volume of an ellipsoid of 239x183x153km * a density of 1.95 g/cm³ yields a mass (m=d*v) of 6.8E+18 kg
  6. ^ Appletons' annual cyclopaedia and register of important events of the year: 1862. New York: D. Appleton & Company. 1863. p. 173. 
  7. ^ Šidlichovský, M. (1999), "Resonances and chaos in the asteroid belt", in Svoren, J.; Pittich, E. M.; Rickman, H., Evolution and source regions of asteroids and comets : proceedings of the 173rd colloquium of the International Astronomical Union, held in Tatranska Lomnica, Slovak Republic, August 24–28, 1998: 297–308, Bibcode:1999esra.conf..297S. 
  8. ^ Mike Nolan (2012-01-18). "Scheduled Arecibo Radar Asteroid Observations". Planetary Radar at Arecibo Observatory. Retrieved 2012-01-23. 
  9. ^ "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. Retrieved 2012-01-23. 
  10. ^ Magri, C. et al. (December 2001), "Radar constraints on asteroid regolith compositions using 433 Eros as ground truth", Meteoritics & Planetary Science 36 (12): 1697–1709, Bibcode:2001M&PS...36.1697M, doi:10.1111/j.1945-5100.2001.tb01857.x. 
  11. ^ "IAUC 8930: COMET P/2006 B7 (ODAS); S/2008 (41) 1; 196P; STEREO SPACECRAFT". IAU Central Bureau for Astronomical Telegrams. 2008-03-31. Retrieved 2008-03-31. 
  12. ^ "Discovery of an Extreme Mass-Ratio Satellite of (41) Daphne in a Close Orbit". Lunar and Planetary Institute. 2008. Retrieved 2011-10-13. 

External links[edit]