Astronomy:41 Daphne

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41 Daphne
Discovery[1]
Discovered byH. Goldschmidt
Discovery dateMay 22, 1856
Designations
(41) Daphne
Pronunciation/ˈdæfni/[2]
Named afterDaphne
1949 TG
Minor planet categoryMain belt
AdjectivesDaphnean /ˈdæfniən/[3]
Orbital characteristics[1]
Epoch 31 December 2006 (JD 2454100.5)
|{{{apsis}}}|helion}}3.517 AU (526.144 Gm)
|{{{apsis}}}|helion}}2.014 AU (301.220 Gm)
2.765 AU (413.682 Gm)
Eccentricity0.272
Orbital period4.60 a (1,679.618 d)
Mean anomaly247.500°
Inclination15.765°
Longitude of ascending node178.159°
46.239°
Known satellitesPeneius /pɛˈniːəs/
(S/2008 (41) 1)
Physical characteristics
Dimensions213×160 km[4]
239x183x153 km[5]
Mean diameter187±13 km[6]
205.495±1.881[1]
189 km[7]
Flattening0.35[lower-alpha 1]
Mass(6.1±0.9)×1018 kg[6]
≈ 6.8×1018 kg[lower-alpha 2]
Mean density1.78±0.45 g/cm3[6]
≈ 1.95 g/cm3[5]
Rotation period5.988 hr[1]
Geometric albedo0.052 (calculated)[6]
0.059±0.007[1]
C[1]
Absolute magnitude (H)7.61[1]


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]

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

Peneius
Daphne and Peneius as seen by the W.M. Keck II telescope in 2008
Designations
(41) Daphne I
Pronunciation/pɛˈniːəs/
S/2008 (41) 1
AdjectivesPeneian /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

  1. ↑ Flattening derived from the maximum aspect ratio (c/a): f=1−ca, where (c/a) = 0.65±0.08.[6]
  2. ↑ 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

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Yeomans, Donald K., "41 Daphne", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=41, retrieved 2013-04-07. 
  2. ↑ "Daphne". Daphne. Oxford University Press. http://www.lexico.com/definition/Daphne. 
  3. ↑ Daphne (3rd ed.), Oxford University Press, September 2005, http://oed.com/search?searchType=dictionary&q=Daphne  (Subscription or UK public library membership required.)
  4. ↑ 4.0 4.1 "1999 European Asteroidal Occultation Results". euraster.net (a website for Asteroidal Occultation Observers in Europe). 2009-02-09. http://www.euraster.net/results/1999/index.html.  (1999-Jul-02 Chords)
  5. ↑ 5.0 5.1 5.2 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". American Astronomical Society 40 (28.12): 438. Bibcode: 2008DPS....40.2812C. http://www2.keck.hawaii.edu/inst/people/conrad/research/pub/dps08oct2008v4b.pdf. 
  6. ↑ 6.0 6.1 6.2 6.3 6.4 P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
  7. ↑ 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. doi:10.1016/j.icarus.2011.07.012. Bibcode: 2011Icar..215...47M. 
  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, doi:10.1051/aas:1999161, Bibcode: 1999A&AS..135...65F. 
  9. ↑ Appletons' annual cyclopaedia and register of important events of the year: 1862. New York: D. Appleton & Company. 1863. p. 173. https://archive.org/stream/1862appletonsan02newyuoft#page/n180/mode/1up. 
  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 (2012-01-18). "Scheduled Arecibo Radar Asteroid Observations". Planetary Radar at Arecibo Observatory. http://www.naic.edu/~pradar/sched.shtml. 
  12. ↑ "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. http://echo.jpl.nasa.gov/asteroids/. 
  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, doi:10.1111/j.1945-5100.2001.tb01857.x, Bibcode: 2001M&PS...36.1697M. 
  14. ↑ "MPEC 2019-E58 : SATELLITE OF (41) Daphne". IAU Minor Planet Center. 2019-03-06. https://www.minorplanetcenter.net/mpec/K19/K19E58.html. 
  15. ↑ "IAUC 8930: COMET P/2006 B7 (ODAS); S/2008 (41) 1; 196P; STEREO SPACECRAFT". IAU Central Bureau for Astronomical Telegrams. 2008-03-31. http://www.cbat.eps.harvard.edu/iauc/08900/08930.html#Item2. 
  16. ↑ "Discovery of an Extreme Mass-Ratio Satellite of (41) Daphne in a Close Orbit". Lunar and Planetary Institute. 2008. http://www.lpi.usra.edu/meetings/acm2008/pdf/8370.pdf. 

vec:Lista de asteroidi#41 Dafne



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