624 Hektor
From Wikipedia, the free encyclopedia
|
Discovery
|
|
|---|---|
| Discovered by | August Kopff |
| Discovery date | February 10, 1907 |
|
Designations
|
|
| Alternative names | 1907 XM; 1948 VD |
| Minor planet category |
Trojan asteroid |
| Epoch October 22, 2004 (JD 2453300.5) | |
| Aphelion | 800.220 Gm (5.349 AU) |
| Perihelion | 762.145 Gm (5.095 AU) |
| Semi-major axis | 781.183 Gm (5.222 AU) |
| Eccentricity | 0.024 |
| Orbital period | 4358.521 d (11.93 a) |
| Average orbital speed | 13.03 km/s |
| Mean anomaly | 94.752° |
| Inclination | 18.198° |
| Longitude of ascending node | 342.791° |
| Argument of perihelion | 183.579° |
|
Physical characteristics
|
|
| Dimensions | 370 × 195 km[1] |
| Mass | ~1.4×1019 kg |
| Mean density | 2 ? g/cm³ |
| Equatorial surface gravity | ~0.067 m/s² |
| Escape velocity | ~0.13 km/s |
| Rotation period | 0.2884 d (6.92 h)[2] |
| Albedo | 0.025 (geometric) [3] |
| Temperature | ~122 K |
| Spectral type | D |
| Apparent magnitude | 13.79 to 15.26 |
| Absolute magnitude | 7.49 |
| Angular diameter | 0.078" to 0.048" |
624 Hektor (pronounced /ˈhektɔr/ hek'-tor) is the largest of the Jovian Trojan asteroids. It was discovered in 1907 by August Kopff.
Hektor is a D-type asteroid, dark and reddish in colour. It lies in Jupiter's leading Lagrangian point, L4, called the 'Greek' node after one of the two sides in the legendary Trojan War. Ironically, Hektor is named after the Trojan hero Hektor, and is thus one of two Trojan asteroids that is "misplaced" in the wrong camp (the other being 617 Patroclus in the Trojan node).
Hektor is one of the most elongated bodies of its size in the solar system, being 370 × 200 km. It is thought that Hektor might be a contact binary (two asteroids joined by gravitational attraction) like 216 Kleopatra. Hubble Space Telescope observations of Hektor in 1993 did not show an obvious bilobated shape because of a limited angular resolution. On July 17 2006, the Keck-10m II telescope and its Laser guide star Adaptive Optics (AO) system indicated a bilobated shape for Hektor. Additionally, since this AO system provides an excellent and stable correction (angular resolution of 0.060 arcsec in K band), a 15-km moonlet at 1000 km of Hektor's primary was detected. The satellite's provisional designation is S/2006 (624) 1[4]. Hektor is, so far, the only known binary trojan asteroid in the L4 point and the first Trojan with a satellite companion. 617 Patroclus, another large Trojan asteroid located in the L5, is composed of two same-sized components.
[edit] References
- ^ Storrs, Alex; Weiss, B.; Zellner, B.; et.al. (1998). "Imaging Observations of Asteroids with Hubble Space Telescope". Icarus 137: 260-268.
- ^ Pole, albedo and shape of the minor planets 624 Hektor and 43 Ariadne. Retrieved on 2007-09-22.
- ^ JPL Small-Body Database Search Engine. Retrieved on 2007-09-22.
- ^ IAUC 8732: S/2006 (624) 1 (Satellite Discovery). Retrieved on 2006-07-23.
[edit] External links
- Orbital simulation from JPL (Java) / Ephemeris
[edit] Hektor in fiction
- See Asteroids in fiction.
|
|||||
