11 Parthenope

11 Parthenope
Deconvolved VLT-SPHERE image of Parthenope
Discovery
Discovered byAnnibale de Gasparis
Discovery siteNaples Obs.
Discovery date11 May 1850
Designations
Pronunciation/pɑːrˈθɛnəpi/ par-THEN-ə-pee
Named after
Parthenopē
Main belt
AdjectivesParthenopean (/ˌpɑːrθənəˈpiːən/ PARTH-ə-nə-PEE-ən)
Parthenopian (/ˌpɑːrθəˈnoʊpiən/ PARTH-ə-NOH-pee-ən)
Symbol𜻄 or 🝺 (historical)
Orbital characteristics
Epoch 17.0 October 2024 (JD 2460600.5)
Uncertainty parameter 0
Observation arc63626 days (174.20 yr)
Aphelion2.69732 AU (403.513 Gm)
Perihelion2.20942 AU (330.525 Gm)
2.45337 AU (367.019 Gm)
Eccentricity0.09943
3.84 yr (1403.6 d)
19.02 km/s
71.503°
0° 15m 23.342s / day
Inclination4.63153°
125.506°
2027-Nov-16
196.071°
Earth MOID1.197 AU (179.1 Gm)
Jupiter MOID2.54059 AU (380.067 Gm)
TJupiter3.483
Physical characteristics
Dimensions156 × 152 × 138 ± 6 km
149±2 km
Mass(4.85±0.12)×1018 kg (2025)
(6.45±0.55)×1018 kg (2023)
Mean density
2.81±0.13 g/cm3 (2025)
3.72±0.35 g/cm3 (2023)
Equatorial surface gravity
0.0578 m/s2
Equatorial escape velocity
0.0941 km/s
13.72204±0.00001 h
73°
312°±2°
17°±4°
0.187 (calculated)
0.191±0.021
Temperature~174 K
S-type asteroid
8.68 to 12.16
6.73
6.55
0.178" to 0.057"

11 Parthenope (also known as A850 JA) is a large, bright asteroid located in the main asteroid belt between the planets of Mars and Jupiter. Parthenope is an S-type asteroid that contains high amounts of silicate material, nickel, and iron.

History & Discovery

Parthenope was discovered by Annibale de Gasparis on 11 May 1850, the second of his nine asteroid discoveries. It was named after Parthenopē, one of the Sirens in Greek mythology, said to have founded the city of Naples. De Gasparis "used his utmost endeavours to realise a 'Parthenope' in the heavens, such being the name suggested by Sir John Herschel on the occasion of the discovery of Hygiea in 1849". Two symbols were proposed for Parthenope: a fish and a star (encoded in Unicode 17.0 as U+1CEC4 𜻄 11 Parthenope fish symbol) while such symbols were still in use, and later a lyre (encoded in Unicode 17.0 as U+1F77A 🝺 11 Parthenope lyre symbol) in lists of symbols. Both are obsolete.

In 1988 a search for satellites or dust orbiting this asteroid was performed using the UH88 telescope at the Mauna Kea Observatories, but the effort came up empty.

Orbit

An orbital diagram of 11 Parthenope, with the orbits of the inner planets and Jupiter shown.

Parthenope orbits the Sun at an average distance (its semi-major axis) of 2.5 astronomical units (AU), with an orbital period of 3.8 years. Its distance from the Sun that varies from 2.20 AU at its perihelion to 2.7 AU at its aphelion, indicated by its orbital eccentricity of 0.1. Parthenope’s orbit is inclined by 4.6° with respect to the ecliptic plane. Parthenope is classified as a background asteroid, as it does not belong to any known asteroid family.

Physical Characteristics

In 2007, Baer and Chesley calculated a higher mass and density for Parthenope based on perturbations by the 90 km asteroid 17 Thetis. Baer and Chesley calculated a mass of 6.3×1018 kg with a density of 3.3 g/cm3. 2008 estimates by Baer suggest a mass of 6.15×1018 kg. The 1997 and 2001 estimates by Viateau and Rapaport were closer to 5×1018 kg with a density of 2.7 g/cm3.

Based upon a light curve that was generated from photometric observations of Parthenope at Pulkovo Observatory, it has a rotation period of 13.722 ± 0.001 hours and varies in brightness by 0.10 ± 0.0s in magnitude. The light curve displays three maxima and minima per cycle. The coloration of the Parthenopean surface is about the average greyish color a typical asteroid would have on their surface area.

See also

Notes

  1. ↑ Calculated from its standard gravitational parameter GM = 0.324±0.008 km3/s2.

References

  1. ↑ Noah Webster (1884) A Practical Dictionary of the English Language
  2. ↑ "Parthenopean". Oxford English Dictionary (online ed.). Oxford University Press. (Subscription or participating institution membership required.), "Parthenopian". Oxford English Dictionary (online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  3. 1 2 3 4 5 "JPL Small-Body Database Browser: 11 Parthenope" (2024-11-29 last obs). Retrieved 20 December 2024.
  4. ↑ "Horizons Batch for 11 Parthenope on 2027-Nov-16" (Perihelion occurs when rdot flips from negative to positive). JPL Horizons. Retrieved 24 October 2026. (JPL#143 Soln.date: 2026-Oct-22)
  5. 1 2 3 4 5 6 7 8 Vernazza, P.; et al. (October 2021). "VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis". Astronomy & Astrophysics. 654: A56. Bibcode:2021A&A...654A..56V. doi:10.1051/0004-6361/202141781. hdl:10045/118969.
  6. 1 2 Fuentes-Muñoz, Oscar; Farnocchia, Davide; Giorgini, Jon D.; Park, Ryan S. (1 December 2025). "Asteroid Mass Estimation by Mutual Perturbations During Close Encounters After Gaia Focused Product Release". The Astronomical Journal. 170 (6): 353. Bibcode:2025AJ....170..353F. doi:10.3847/1538-3881/ae0cc9. ISSN 0004-6256. S2CID 283347135.
  7. 1 2 Li 李, Fan 凡; Yuan 袁, Ye 烨; Fu 傅, Yanning 燕宁; Chen 陈, Jian 健 (1 September 2023). "Dynamical Masses of 20 Asteroids Determined with Gaia DR3 Asteroid Observations". The Astronomical Journal. 166 (3): 93. Bibcode:2023AJ....166...93L. doi:10.3847/1538-3881/ace52b. ISSN 0004-6256. S2CID 260534542.
  8. ↑ "AstDys (11) Parthenope Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 26 June 2010.
  9. ↑ De Gasparis, Annibale (May 1850). "The New Planet Parthenope". Monthly Notices of the Royal Astronomical Society. 10: 144–147. Bibcode:1850MNRAS..10..144D. doi:10.1093/mnras/10.7.144.
  10. ↑ Bala, Gavin Jared; Miller, Kirk (18 September 2023). "Unicode request for historical asteroid symbols" (PDF). unicode.org. Unicode. Retrieved 26 September 2023.
  11. ↑ "Miscellaneous Symbols Supplement" (PDF). unicode.org. The Unicode Consortium. 2025. Retrieved 9 September 2025.
  12. ↑ "Alchemical Symbols" (PDF). unicode.org. The Unicode Consortium. 2025. Retrieved 17 September 2025.
  13. ↑ Gradie, J.; Flynn, L. (March 1988), "A Search for Satellites and Dust Belts Around Asteroids: Negative Results", Abstracts of the Lunar and Planetary Science Conference, vol. 19, pp. 405–406, Bibcode:1988LPI....19..405G.
  14. ↑ "(11) Parthenope – Proper Elements". Asteroids Dynamic Site. Retrieved 24 January 2026.
  15. 1 2 Baer, James; Steven R. Chesley (2008). "Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris". Celestial Mechanics and Dynamical Astronomy. 100 (2008). Springer Science+Business Media B.V. 2007: 27–42. Bibcode:2008CeMDA.100...27B. doi:10.1007/s10569-007-9103-8.
  16. ↑ Jim Baer (2008). "Recent Asteroid Mass Determinations". Personal Website. Archived from the original on 2 July 2013. Retrieved 6 December 2008.
  17. ↑ Pilcher, Frederick (October 2011), "Rotation Period Determinations for 11 Parthenope, 38 Leda, 111 Ate 194 Prokne, 217 Eudora, and 224 Oceana", The Minor Planet Bulletin, vol. 38, no. 4, pp. 183–185, Bibcode:2011MPBu...38..183P.