5335 Damocles

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5335 Damocles
Discovered by Robert H. McNaught
Discovery date 18 February 1991
Named after
1991 DA
Orbital characteristics[2]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 4
Observation arc 551 days (1.51 yr)
Aphelion 22.084 AU (3.3037 Tm)
Perihelion 1.5715 AU (235.09 Gm)
11.828 AU (1.7694 Tm)
Eccentricity 0.86714
40.68 yr (14858 d)
6.67 km/s
0° 1m 27.224s / day
Inclination 62.042°
Earth MOID 0.595945 AU (89.1521 Gm)
Mars MOID 0.05787 AU[1]
Jupiter MOID 3.58771 AU (536.714 Gm)
Jupiter Tisserand parameter 1.144
Physical characteristics
Dimensions ~ 10 km
10.2 h
S[citation needed]

5335 Damocles (/ˈdæməklz/ DAM-ə-kleez) is the archetype of the damocloids, asteroids that are inactive nuclei of the Halley family and long-period comets. It was discovered in 1991 and named after Damocles, a figure of Greek mythology.

When Damocles was discovered, in 1991 by Robert H. McNaught, 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.[4] 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.[5][6]

There is some speculation that 5335 Damocles may have a meteor shower associated with it on Mars from the direction of Draco.[7] The object has a Mars minimum orbit intersection distance (Mars–MOID) of 0.057 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).[1]

As of 2014, Damocles is 21.8 AU from the Sun with an apparent magnitude of 26.9.[3]

The adjectival form is Damoclean, /dæməˈkliːən/.[8]

See also[edit]


  1. ^ a b "(5335) Damocles = 1991 DA Orbit". IAU Minor Planet Center. Retrieved 2014-11-15. 
  2. ^ "5335 Damocles (1991 DA)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 11 April 2016. 
  3. ^ a b "AstDyS Damocles Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2014-04-05. 
  4. ^ Steel, D. (1995). Rogue asteroids and doomsday comets. Wiley & Sons, p. 127–128
  5. ^ Asher, David J.; Bailey; Hahn; Steel (1994). "Asteroid 5335 Damocles and its implications for cometary dynamics". Monthly Notices of the Royal Astronomical Society. 267: 26. Bibcode:1994MNRAS.267...26A. doi:10.1093/mnras/267.1.26. 
  6. ^ Asher, David; Bailey, Mark; Hahn, Gerhard; Steel, Duncan (27 May 1993). "Asteroid 5335 Damocles and its implications for cometary dynamics". mnras.oxfordjournals.org. Royal Astronomical Society. ISSN 0035-8711. Archived from the original on 17 July 2016. Retrieved 17 July 2016. 
  7. ^ Meteor Showers and Their Parent Bodies
  8. ^ OED

External links[edit]