60558 Echeclus
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| Discovery A | |
|---|---|
| Discoverer | Spacewatch |
| Discovery date | March 3, 2000 |
| Alternate designations B |
2000 EC98 |
| Category | centaur |
| Orbital elements C | |
|
|
|
| Eccentricity (e) | 0.456 |
| Semi-major axis (a) | 1611.498 Gm (10.772 AU) |
| Perihelion (q) | 876.276 Gm (5.858 AU) |
| Aphelion (Q) | 2346.719 Gm (15.687 AU) |
| Orbital period (P) | 12913.822 d (35.36 a) |
| Mean orbital speed | 8.58 km/s |
| Inclination (i) | 4.335° |
| Longitude of the ascending node (Ω) |
173.319° |
| Argument of perihelion (ω) |
162.366° |
| Mean anomaly (M) | 275.435° |
| Physical characteristics D | |
| Dimensions | 70 km[1] |
| Mass | 3.6×1017? kg |
| Density | 2.0? g/cm³ |
| Surface gravity | 0.0196? m/s² |
| Escape velocity | 0.0370? km/s |
| Rotation period | ? d |
| Spectral class | ? |
| Absolute magnitude | 9.5 |
| Albedo (geometric) | 0.10? |
| Mean surface temperature |
~85 K |
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 2000 EC98, also written as 2000 EC98. Research in 2001 by Rousselot and Petit at the Besancon observatory in France showed no evidence of cometary activity, but in late December 2005 a cometary coma was detected. In early 2006[2] the Committee on Small Bodies Nomenclature gave it the cometary designation 174P/Echeclus.
Echeclus is only the second comet (after Chiron) that has the same name as an asteroid (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.
Three other objects are cross-listed as both comets and asteroids: 133P/Elst-Pizarro (7968 Elst-Pizarro), 4015 Wilson-Harrington (107P/Wilson-Harrington), and 118401 LINEAR (176P/LINEAR (LINEAR 52)).
On 11 April 2006, 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.[3]
[edit] References
- ^ http://www.johnstonsarchive.net/astro/tnoslist.html
- ^ Homepage of the VdS-Fachgruppe Kometen. Retrieved on 2006-04-18.
- ^ Hecht, Jeff (11 April 2006). Hybrid comet-asteroid in mysterious break-up. NewScientist.com news service. Retrieved on 2006-04-18.
[edit] External links
| Minor planets | ||
|---|---|---|
| Previous minor planet | 60558 Echeclus | Next minor planet |
| List of asteroids | ||
| Comets | ||
|---|---|---|
| Previous periodic comet | 174P/Echeclus | Next periodic comet |
| List of periodic comets | ||
Vulcanoids · Near-Earth asteroids · Main belt · Jupiter Trojans · Centaurs · Damocloids · Comets · Trans-Neptunians (Kuiper belt • Scattered disc • Oort cloud)
For other objects and regions, see Asteroid groups and families, Binary asteroids, Asteroid moons and the Solar System.
For a complete listing, see List of asteroids. See also Pronunciation of asteroid names and Meanings of asteroid names.
