60558 Echeclus

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60558 Echeclus
Discovered by Spacewatch
Discovery site Kitt Peak
Discovery date 3 March 2000
Pronunciation /ˈkɛkləs/ e-KEK-ləs
or /ˈɛkkləs/ EK-i-kləs
2000 EC98, 2002 GJ27
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc 13264 days (36.31 yr)
Aphelion 15.544 AU (2.3253 Tm)
Perihelion 5.8168 AU (870.18 Gm)
10.680 AU (1.5977 Tm)
Eccentricity 0.45537
34.90 yr (12749 d)
8.58 km/s
0° 1m 41.657s / day
Inclination 4.3445°
Earth MOID 4.80578 AU (718.934 Gm)
Jupiter MOID 0.838867 AU (125.4927 Gm)
Jupiter Tisserand parameter 3.031
Proper orbital elements
0.0282 deg / yr
12765.95745 yr
(4662765.957 d)
Physical characteristics
Dimensions 84 km[2][3]
26.802 h (1.1168 d)[1]
Temperature ~85 K

60558 Echeclus is a centaur in the outer Solar System. It was discovered by Spacewatch in 2000 and initially classified as a minor planet with provisional designation 2000 EC98 (also written 2000 EC98). Research in 2001 by Rousselot and Petit at the Besançon observatory in France showed no evidence of cometary activity, but in late December 2005 a cometary coma was detected. In early 2006[5] the Committee on Small Bodies Nomenclature (CSBN) gave it the cometary designation 174P/Echeclus. It next comes to perihelion in April 2015,[1] and is expected to reach about apparent magnitude 16.7 near opposition in September 2015.[6]


Echeclus (Greek: Έχεκλος) is a centaur in Greek mythology.

60558 Echeclus is only the second comet (after Chiron) that was named as an asteroid, rather than after the name of its discoverer. Chiron is also a centaur; other centaurs are being observed for signs of a cometary coma.

Besides Chiron, three other objects are cross-listed as both comets and asteroids: 7968 Elst–Pizarro (133P/Elst–Pizarro), 4015 Wilson–Harrington (107P/Wilson–Harrington), and 118401 LINEAR (176P/LINEAR).[7]


On 30 December 2005, when 13.1 AU from the Sun, a large chunk of Echeclus was observed to break off, causing a great cloud of dust. Astronomers have speculated this could have been caused by an impact or by an explosive release of volatile substances.[8]

2011 outburst[edit]

Echeclus appears to have outburst again around June 2011 when it was 8.5 AU from the Sun.[9][10] On 24 June 2011, follow up imaging with the 2 meter Haleakala-Faulkes Telescope South showed the coma of Echeclus to be very close to the sky background limit.[11]


Echeclus came to perihelion in April 2015.[1]

Centaurs have short dynamical lives due to strong interactions with the giant planets. Echeclus is estimated to have an orbital half-life of about 610,000 years.[12]

See also[edit]


  1. ^ a b c d e "60558 Echeclus (2000 EC98)". JPL Small-Body Database. Jet Propulsion Laboratory. SPK-ID: 2060558. Retrieved 12 April 2016. 
  2. ^ Wm. Robert Johnston (22 August 2008). "List of Known Trans-Neptunian Objects". Johnston's Archive. Archived from the original on 16 December 2006. Retrieved 2006-12-26. 
  3. ^ a b John Stansberry; Will Grundy; Mike Brown; Dale Cruikshank; John Spencer; David Trilling; Jean-Luc Margot (2007). "Physical Properties of Kuiper Belt and Centaur Objects: Constraints from Spitzer Space Telescope". arXiv:astro-ph/0702538free to read [astro-ph]. 
  4. ^ "AstDys (60558) Echeclus Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2010-06-28. 
  5. ^ "Homepage of the VdS-Fachgruppe Kometen". Archived from the original on 24 April 2006. Retrieved 2006-04-18. 
  6. ^ "Elements and Ephemeris for 174P/Echeclus". Minor Planet Center. Retrieved 2014-10-31.  (0174P)
  7. ^ Dual-Status Objects
  8. ^ Hecht, Jeff (11 April 2006). "Hybrid comet-asteroid in mysterious break-up". NewScientist.com news service. Retrieved 2006-04-18. 
  9. ^ Giovanni Sostero & Ernesto Guido (June 1, 2011). "Outburst of 174P/Echeclus". Team of observers of Remanzacco Observatory in Italy. Retrieved 2011-06-01. 
  10. ^ Giovanni Sostero & Ernesto Guido (June 9, 2011). "Follow-up of 174P/Echeclus bright phase". Team of observers of Remanzacco Observatory in Italy. Retrieved 2011-06-09. 
  11. ^ Nick Howes; Giovanni Sostero & Ernesto Guido (June 24, 2011). "Further follow-up of 174P/Echeclus". Team of observers of Remanzacco Observatory in Italy. Retrieved 2011-06-24. 
  12. ^ Horner, J.; Evans, N.W.; Bailey, M. E. (2004). "Simulations of the Population of Centaurs I: The Bulk Statistics". Monthly Notices of the Royal Astronomical Society. 354 (3): 798. arXiv:astro-ph/0407400free to read. Bibcode:2004MNRAS.354..798H. doi:10.1111/j.1365-2966.2004.08240.x. 

External links[edit]

Numbered comets
174P/Echeclus Next