60558 Echeclus
Encyclopedia
60558 Echeclus is a centaur
in the outer Solar System
. It was discovered by Spacewatch
in 2000 and initially classified as an asteroid
with provisional designation (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 the Committee on Small Bodies Nomenclature (CSBN) gave it the comet
ary designation 174P/Echeclus.
) that has an asteroid-like name (rather than the name of its discoverer(s) as with other comets). 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).
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
.
showed the coma of Echeclus to be very close to the sky background limit.
in 2015.
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 kiloannum.
Centaur (planetoid)
Centaurs are an unstable orbital class of minor planets that behave with characteristics of both asteroids and comets. They are named after the mythological race of beings, centaurs, which were a mixture of horse and human...
in the outer Solar System
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
. It was discovered by Spacewatch
Spacewatch
Spacewatch is a project at the University of Arizona led by Robert S. McMillan that specializes in the study of minor planets, including various types of asteroids and comets...
in 2000 and initially classified as an asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
with provisional designation (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
Coma (cometary)
frame|right|The [[153P/Ikeya-Zhang|comet Ikeya-Zhang]] exhibiting a bright, condensed coma In astronomy, a coma is the nebulous envelope around the nucleus of a comet. It is formed when the comet passes close to the Sun on its highly elliptical orbit; as the comet warms, parts of it sublimate...
was detected. In early 2006 the Committee on Small Bodies Nomenclature (CSBN) gave it the comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
ary designation 174P/Echeclus.
Name
Echeclus is only the second comet (after Chiron2060 Chiron
2060 Chiron is a minor planet in the outer Solar System. Discovered in 1977 by Charles T. Kowal , it was the first-known member of a new class of objects now known as centaurs, with an orbit between Saturn and Uranus.Although it was initially classified as an asteroid, it was later found to...
) that has an asteroid-like name (rather than the name of its discoverer(s) as with other comets). 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
118401 LINEAR
118401 LINEAR is an asteroid and main-belt comet which was discovered by the Lincoln Near-Earth Asteroid Research 1-metre telescopes in Socorro, New Mexico on September 7, 1999. LINEAR was discovered to be cometary on November 26, 2005, by Henry H. Hsieh and David C...
(176P/LINEAR).
Chunk
On 30 December 2005, when 13.1 AUAstronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
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
Volatiles
In planetary science, volatiles are that group of chemical elements and chemical compounds with low boiling points that are associated with a planet's or moon's crust and/or atmosphere. Examples include nitrogen, water, carbon dioxide, ammonia, hydrogen, and methane, all compounds of C, H, O...
.
2011 outburst
Echeclus appears to have outburst again around June 2011 when it was 8.5 AU from the Sun. On 24 June 2011, follow up imaging with the 2 meter Haleakala-Faulkes Telescope SouthFaulkes Telescope South
The Faulkes Telescope South is a clone of the Liverpool Telescope and is located at Siding Spring Observatory. It is a Ritchey-Chrétien telescope....
showed the coma of Echeclus to be very close to the sky background limit.
Orbit
Echeclus comes to perihelionApsis
An apsis , plural apsides , is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system...
in 2015.
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 kiloannum.
External links
- Orbital simulation from JPL (Java) / Ephemeris
- Elements and Ephemeris for 174P/Echeclus (IAU Minor Planet Center)
- BAA Comet Section : Comets discovered in 2006
- 60558 - 0174P/ Echeclus (2011 Jun 08)
- Comet 174P Echeclus chased by Asteroid 2716 Tuulikki (Animation by Joseph Brimacombe on 30 May 2011)