Astronomy:5335 Damocles

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(5335) Damocles Damocles symbol.svg
Discovery
Discovered byR. H. McNaught
Discovery siteSiding Spring Obs.
Discovery date18 February 1991
Designations
(5335) Damocles
Pronunciation/ˈdæməklz/[5]
Named afterDamocles (Greek mythology)[1]
1991 DA
Minor planet categorydistant[2]
centaur[3] · damocloid [4]
AdjectivesDamoclean (/dæməˈkliːən/)[6]
Orbital characteristics[3]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 4
Observation arc1.51 yr (551 days)
|{{{apsis}}}|helion}}22.078 AU
|{{{apsis}}}|helion}}1.5741 AU
11.826 AU
Eccentricity0.8669
Orbital period40.67 Jyr (14,854 days)
Mean anomaly236.35°
Mean motion0° 1m 27.12s / day
Inclination61.875°
Longitude of ascending node314.14°
191.26°
Mars MOID0.05787 AU[2]
TJupiter1.149
Physical characteristics
Dimensions~ 10 km[7]
Apparent magnitude26.56[8]
Absolute magnitude (H)13.3[3][8]


(5335) Damocles /ˈdæməklz/, provisional designation 1991 DA, is a centaur and the namesake of the damocloids, a group of minor planets which may be inactive nuclei of the Halley-type and long-period comets. It was discovered on 18 February 1991, by Australian astronomer Robert McNaught at Siding Spring Observatory in Australia. It is named after Damocles, a figure of Greek mythology.[1]

Description

When Damocles was discovered, it was found to be on an orbit completely different from all others known. Damocles's orbit reached from inside the aphelion of Mars to as far as Uranus. It seemed to be in transition from a near-circular outer Solar System orbit to an eccentric orbit taking it to the inner Solar System.[9] Duncan Steel, Gerhard Hahn, Mark Bailey, and David Asher carried out projections of its long-term dynamical evolution, and found a good probability that it will become an Earth-crosser asteroid, and may spend a quarter of its life in such an orbit. Damocles has a stable orbit for tens of thousands of years before and after the present, because its highly inclined orbit does not take it near Jupiter or Saturn.[10][11]

There is some speculation that Damocles may have a meteor shower associated with it on Mars from the direction of Draco.[12] The object has a Mars minimum orbit intersection distance (Mars MOID) of 0.057 astronomical unit|AU (8,500,000 km; 5,300,000 mi) and a Uranus MOID of 0.3 AU (45,000,000 km; 28,000,000 mi).[2]

(As of 2019), Damocles is 19.6 AU from the Sun with an apparent magnitude of 26.3 .[8] It reached its furthest point from the Sun in 2011.

The adjectival form is Damoclean, /dæməˈkliːən/.[6] The official naming citation was published by the Minor Planet Center on 1 September 1993 (M.P.C. 22508).[13]

See also

  • The sword of Damocles – an over-hanging threat, a long-standing political metaphor from ancient Greece.

References

  1. 1.0 1.1 Schmadel, Lutz D. (2007). "(5335) Damocles". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 457. doi:10.1007/978-3-540-29925-7_5143. ISBN 978-3-540-00238-3. 
  2. 2.0 2.1 2.2 "(5335) Damocles (1991 DA)". https://www.minorplanetcenter.net/db_search/show_object?object_id=5335. 
  3. 3.0 3.1 3.2 "1992-08-22 last obs.". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2005335. 
  4. Akimasa Nakamura and bas (2 May 2009). "List of Damocloids (Oort cloud asteroids)". Lowell Observatory. http://ftp.lowell.edu/pub/bas/damocloid. 
  5. Webster, Noah (1884). A Practical Dictionary of the English Language. 
  6. 6.0 6.1 Oxford English Dictionary
  7. Johnston, Wm. Robert (25 May 2019). "List of known trans-Neptunian objects". http://www.johnstonsarchive.net/astro/tnoslist.html. 
  8. 8.0 8.1 8.2 "AstDyS Damocles Ephemerides". Department of Mathematics, University of Pisa, Italy. https://newton.spacedys.com/astdys/index.php?pc=1.1.3.0&n=Damocles. 
  9. Steel, D. (1995). Rogue Asteroids and Doomsday Comets. Wiley & Sons. pp. 127–128. 
  10. "Asteroid (5335) Damocles and its implications for cometary dynamics". Monthly Notices of the Royal Astronomical Society 267: 26. 1994. doi:10.1093/mnras/267.1.26. Bibcode1994MNRAS.267...26A. 
  11. Asher, David; Bailey, Mark; Hahn, Gerhard; Steel, Duncan (27 May 1993). "Asteroid (5335) Damocles and its implications for cometary dynamics". Monthly Notices of the Royal Astronomical Society 267: 26–42. doi:10.1093/mnras/267.1.26. Bibcode1994MNRAS.267...26A. 
  12. "Meteor Showers and Their Parent Bodies". http://star.arm.ac.uk/~aac/showers.jpg. 
  13. "MPC/MPO/MPS Archive". https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html. 

External links