astro.wikisort.org - Asteroid

60558 Echeclus /ˈɛkɪkləs/ is a centaur, approximately 84 kilometers (52 miles) in diameter, located 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 indicated that it was not a comet, but in December 2005 a cometary coma was detected. In early 2006[6] the Committee on Small Bodies Nomenclature (CSBN) gave it the cometary designation 174P/Echeclus. It last came to perihelion in April 2015,[1] and was expected to reach about apparent magnitude 16.7 near opposition in September 2015.[7]

60558 Echeclus
174P/Echeclus

Discovery
Discovered by	Spacewatch
Discovery site	Kitt Peak Obs.
Discovery date	3 March 2000
Designations
MPC designation	(60558) Echeclus
Pronunciation	/ˈɛkɪkləs/
Named after	Ἔχεκλος Ekheklos
Alternative designations	2000 EC98, 2002 GJ27
Minor planet category	Centaur
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)
Semi-major axis	10.680 AU (1.5977 Tm)
Eccentricity	0.45537
Orbital period (sidereal)	34.90 yr (12749 d)
Average orbital speed	8.58 km/s
Mean anomaly	7.51102°
Mean motion	0° 1m 41.657s / day
Inclination	4.3445°
Longitude of ascending node	173.335°
Argument of perihelion	162.889°
Jupiter MOID	0.838867 AU (125.4927 Gm)
TJupiter	3.031
Proper orbital elements
Proper mean motion	0.0282 deg / yr
Proper orbital period	12765.95745 yr (4662765.957 d)
Physical characteristics
Mean diameter	84 km[2][3]
Synodic rotation period	26.802 h (1.1168 d)[1]
Geometric albedo	0.04[3]
Temperature	~85 K
Spectral type	B–V = 0.841±0.072[4] V–R = 0.502±0.065[4]
Apparent magnitude	~18.8[5]
Absolute magnitude (H)	9.6[1]

Name

Echeclus is a centaur in Greek mythology.

60558 Echeclus is only the second comet (after Chiron) that was named as a minor planet, 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 Echeclus, eight other objects are cross-listed as both comets and numbered minor planets: 2060 Chiron (95P/Chiron), 4015 Wilson–Harrington (107P/Wilson–Harrington), 7968 Elst–Pizarro (133P/Elst–Pizarro), 118401 LINEAR (176P/LINEAR), (323137) 2003 BM80 (282P/2003 BM₈₀), (300163) 2006 VW139 (288P/2006 VW₁₃₉), (457175) 2008 GO98 (362P/2008 GO₉₈),[8] and (248370) 2005 QN173 (433P/2005 QN₁₇₃).[9]

Chunk

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.[10]

Outbursts

Echeclus appears to have outburst again around June 2011 when it was 8.5 AU from the Sun.[11][12] 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.[13]

Echeclus outburst again around 7 December 2017 when it was 7.3 AU from the Sun, and was 4 magnitudes brighter than expected.[14]

Presence of gas

In 2016, carbon monoxide was detected in Echeclus in very small amounts, and the derived CO production rate was calculated to be sufficient to account for the observed coma. The calculated CO production rate from Echeclus is substantially lower than what is typically observed for 29P/Schwassmann–Wachmann, another distantly active comet often classified as a centaur.[15]

Orbit

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.[16]

See also

• List of centaurs (small Solar System bodies) § 60558

References

External links

• Elements and Ephemeris for 174P/Echeclus (IAU Minor Planet Center)
• BAA Comet Section : Comets discovered in 2006
• 60558 - 0174P/ Echeclus (2011 June 8)
• Comet 174P Echeclus chased by Asteroid 2716 Tuulikki (Animation by Joseph Brimacombe on 30 May 2011)
• Comet 174P/ Echeclus during its 2016 outburst (Virtual Telescope Project)
• 60558 Echeclus at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 60558 Echeclus at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

Numbered comets
Previous 173P/Mueller	174P/Echeclus	Next 175P/Hergenrother

На других языках

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[de] (60558) Echeclus

(60558) Echeclus ist ein Asteroid des Zentauren-Typs, der am 3. März 2000 im Rahmen des Spacewatch-Programms entdeckt wurde.

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- [en] 60558 Echeclus

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[es] (60558) Echeclus

60558 Echeclus es un planeta menor del Sistema Solar exterior, descubierto por el Spacewatch en 2000 e inicialmente clasificado como un asteroide con la designación provisional 2000 EC98 (también 2000 EC98). Observado en 2001 por Rousselot y Petit en el observatorio Besançon en Francia no mostró evidencias de actividad como cometa, pero a finales de diciembre de 2005 se le detectó una coma. A principios de 2006[3] el CSBN le dio la designación cometaria 174P/Echeclus.

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[ru] (60558) Эхекл

(60558) Эхе́кл (лат. Echeclus) — небольшой астероид из группы кентавров, также известный как комета 174P/Эхекл. Он был открыт 3 марта 2000 года группой американских астрономов в составе Джеймса Скотти, A. E. Gleason, J. L. Montani и M. T. Read во время работы в обсерватории Китт-Пик в рамках проекта Spacewatch. Он был описан как звёздоподобный объект 21,0 m звёздной величины и получил временное обозначение 2000 EC98, а чуть позже порядковый номер и название. Поскольку орбита объекта указывала на его принадлежность к группе кентавров, то и имя он получил в честь мифического кентавра Эхекла, погибшего в битве с лапифами.

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