41 Daphne

Daphne (minor planet designation: 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]

Not to be confused with Daphnis (moon).
41 Daphne
Daphne and Peneius as seen by the W.M. Keck II telescope in 2008
Discovery[1]
Discovered byH. Goldschmidt
Discovery dateMay 22, 1856
Designations
(41) Daphne
Pronunciation/ˈdæfniː/[2]
Named after
Daphnē
1949 TG
Main belt
AdjectivesDaphnean /ˈdæfniən/[3]
Orbital characteristics[1]
Epoch 31 December 2006 (JD 2454100.5)
Aphelion3.517 AU (526.144 Gm)
Perihelion2.014 AU (301.220 Gm)
2.765 AU (413.682 Gm)
Eccentricity0.272
4.60 a (1,679.618 d)
247.500°
Inclination15.765°
178.159°
46.239°
Known satellitesPeneius /pɛˈniːəs/
(S/2008 (41) 1)
Physical characteristics
Dimensions174.0 ± 11.2 km[1]
189 km[4]
213×160 km[5]
239x183x153 km[6]
Mass~6.8×1018 kg[7]
Mean density
~1.95 g/cm³[6]
5.9 hr[1]
0.083[1]
C [1]
7.12[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.[5] 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

    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,[6] 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]

    References
    1. Yeomans, Donald K., "41 Daphne", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 7 April 2013.
    2. Noah Webster (1884) A Practical Dictionary of the English Language
    3. "Daphne". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public library membership required.)
    4. 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.
    5. "1999 European Asteroidal Occultation Results". euraster.net (a website for Asteroidal Occultation Observers in Europe). 9 February 2009. Retrieved 1 December 2008. (1999-Jul-02 Chords)
    6. Conrad, Al; Carry, B.; Drummond, J. D.; Merline, W. J.; Dumas, C.; Owen, W. M.; et al. (2008). "Shape and Size of Asteroid (41) Daphne from AO Imaging" (PDF). American Astronomical Society. 40 (28.12): 438. Bibcode:2008DPS....40.2812C. Archived from the original (PDF) on 18 September 2009.
    7. 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
    8. Fornasier, S.; et al. (February 1999), "Spectroscopic comparison of aqueous altered asteroids with CM2 carbonaceous chondrite meteorites", Astronomy and Astrophysics Supplement, 135: 65−73, Bibcode:1999A&AS..135...65F, doi:10.1051/aas:1999161.
    9. Appletons' annual cyclopaedia and register of important events of the year: 1862. New York: D. Appleton & Company. 1863. p. 173.
    10. Šidlichovský, M. (1999), Svoren, J.; Pittich, E. M.; Rickman, H. (eds.), "Resonances and chaos in the asteroid belt", 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, pp. 297–308, Bibcode:1999esra.conf..297S.
    11. Mike Nolan (18 January 2012). "Scheduled Arecibo Radar Asteroid Observations". Planetary Radar at Arecibo Observatory. Retrieved 23 January 2012.
    12. "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. Retrieved 23 January 2012.
    13. 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.
    14. "MPEC 2019-E58 : SATELLITE OF (41) Daphne". IAU Minor Planet Center. 6 March 2019. Retrieved 7 March 2019.
    15. "IAUC 8930: COMET P/2006 B7 (ODAS); S/2008 (41) 1; 196P; STEREO SPACECRAFT". IAU Central Bureau for Astronomical Telegrams. 31 March 2008. Retrieved 31 March 2008.
    16. "Discovery of an Extreme Mass-Ratio Satellite of (41) Daphne in a Close Orbit" (PDF). Lunar and Planetary Institute. 2008. Retrieved 13 October 2011.

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