(130) Electra
Asteroid (130) Electra |
|
---|---|
Properties of the orbit ( animation ) | |
Orbit type | Outer main belt |
Major semi-axis | 3.1302 AU |
eccentricity | 0.2080 |
Perihelion - aphelion | 2.4790 AU - 3.7814 AU |
Inclination of the orbit plane | 22.772 ° |
Length of the ascending node | 145.197 ° |
Argument of the periapsis | 236.855 ° |
Time of passage of the perihelion | February 23, 2020 |
Sidereal period | 5 a 198 d |
Mean orbital velocity | 16.66 km / s |
Physical Properties | |
Medium diameter | 180.7 km ± 2.7 km |
Dimensions | 215 × 155 ± 12 |
Dimensions | 6.6 ± 0.4 · 10 18 | kg
Albedo | 0.071 ± 0.011 |
Medium density | 1.3 ± 0.3 g / cm³ |
Rotation period | 5 h 13 min 28.8 s |
Absolute brightness | 7.12 likes |
Spectral class (according to Tholen) |
G |
Spectral class (according to SMASSII) |
Ch |
history | |
Explorer | Christian HF Peters |
Date of discovery | February 17, 1873 |
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items. |
(130) Elektra is an asteroid of the outer main asteroid belt . With a mean diameter of 181 km, Elektra is one of the largest asteroids in the main belt. Elektra has two moons : S / 2003 (130) 1 and S / 2014 (130) 1 with diameters of about 6 and 5 km, respectively.
Discovery and naming
Elektra was discovered on February 17, 1873 by the German-American astronomer Christian Heinrich Friedrich Peters at the Litchfield Observatory in Clinton , New York ( USA ).
The celestial body was named after Elektra , the daughter of the king of Mycenae and Clytaimnestra from Greek mythology .
In total, the asteroid was observed through several earth-based telescopes, a total of 2324 times within 123 years. (As of Sept. 2017)
Track properties
Orbit
Elektra orbits the sun in a prograde , elliptical orbit between 370,850,000 km (2.48 AU ) and 565,700,000 km (3.78 AU) from its center. The orbit eccentricity is 0.208, the orbit is strongly inclined with 22.8 ° in relation to the ecliptic . Its orbit is therefore in the outer asteroid belt .
The orbital period of Elektra is 5.54 years.
rotation
Elektra rotates once around its axis in 5 hours, 13 minutes 29 seconds. From this it follows that the asteroid performs 9,291.8 self- rotations (“days”) in an Elektra year . The axis of rotation is approximately perpendicular to the ecliptic .
Physical Properties
size
The observations made so far indicate an irregularly shaped, elongated body; the most precise determination of the diameter ( geometric mean ) is 180.652 km. With regard to the exact dimensions, the most precise value is 215 × 155 km.
In the late 1990s, light curve data was collected by a worldwide network of astronomers to determine the rotation and shape of 10 asteroids, including Elektra. Elektra's light curve describes a double sinusoid , while the model of the shape indicates a more elongated shape.
Assuming a mean diameter of 180.7 km, the surface area is around 103,000 km 2 , which is roughly the size of Iceland .
year | Dimensions km | source |
---|---|---|
2004 | 182.25 ± 11.8 | Tedesco ( IRAS ) et al. |
2004 | 215 × 155 ± 12 | Tedesco (IRAS) et al. |
2006 | 191 | Marchis et al. |
2011 | 198.93 ± 4.11 | Masiero et al. |
2014 | 180.652 ± 2.698 | Masiero et al. |
The most precise / most recent determination is marked in bold .
internal structure
Elektra belongs to the G-type asteroids (according to another classification: Ch) and therefore has a dark, carbon-rich surface with an albedo of 0.071; spectral examinations confirmed the presence of organic matter. The surface of Elektra shows differences in brightness of 5–15%.
The density is 1.3 g / cm 3 ; However, there is still some uncertainty here, it is also given as a significantly higher 3.5-4.1 g / cm 3 . Due to the discovery of the two moons, the mass has so far been calculated to be 6.6 ∙ 10 18 , based on a density of 1.3 g / cm³.
The mean surface temperature is around 157 K (−116 ° C) and can rise to a maximum of 251 K (−22 ° C) at noon; at night it can drop to 63 K (−210 ° C).
The Elektra triple system
On August 15, 2003, the Keck Telescope II, a first companion at Elektra , was discovered using adaptive optics . The moon , initially designated as S / 2003 (130) 1 , has a diameter of 6 km and orbits Elektra at a distance of 1,318 km in 5.26 days.
Through further observations with the Very Large Telescope in December 2014, another companion could be found, which was named S / 2014 (130) 1 . This orbits Elektra within the orbit of the outer moon and is 5.2 km in size; it moves around the asteroid at a distance of 460 km in 1.10 days.
After (87) Sylvia , (45) Eugenia , (3749) Balam , (216) Cleopatra and (93) Minerva, Elektra is the sixth discovered multiple asteroid system in the main belt. Apart from the dwarf planets Pluto and Haumea - which also have an asteroid number - according to Sylvia, Eugenia, (47171) Lempo , (153591) 2001 SN 263 , Balam, Cleopatra, (136617) 1994 CC , Minerva and ( 2577) Litva the tenth known asteroid multiple system in the solar system.
The Elektra system at a glance:
Components | Physical parameters | Path parameters | discovery | |||||
---|---|---|---|---|---|---|---|---|
Surname | Throughput diameter (km) |
Relative size % |
Mass (kg) |
Major semi-axis (km) |
Orbital time (d) |
eccentricity | Inclination to Electra's equator |
Date of discovery Date of publication |
(130) Electra | 182.7 | 100.00 | 6.6 · 10 18 | - | - | - | - | February 17, 1873 1873 |
S / 2014 (130) 1 (Elektra II) |
5.2 | 2.9 | ? | 460 | 1,100 | 0.10 | 46.0 | December 6, 2014 December 16, 2014 |
S / 2003 (130) 1 (Elektra I) |
6.0 | 3.3 | 4.0 · 10 14 | 1318 | 5.258 | 0.13 | 3.0 | August 15, 2003 August 17, 2003 |
See also
Web links
- (130) Elektra, S / 2003 (130) 1, and S / 2014 (130) 1 Wm. Robert Johnston (English)
- Elektra: A new triple asteroid. ESO; with photo
Individual evidence
- ↑ (130) Elektra in the Small-Body Database of the Jet Propulsion Laboratory (English).
- ↑ Joseph Ďurech et al .: Physical models of asteroids from ten to observers' collaboration network . April 2007, bibcode : 2007A & A ... 465..331D .
- ↑ a b E. F. Tedesco et al .: IRAS Minor Planet Survey V6.0 . October 2006. bibcode : 2004PDSS ... 12 ..... T .
- ^ Franck Marchis et al .: Shape, size and multiplicity of main-belt asteroids I. Keck Adaptive Optics survey . November 2006, PMC 2600456 (free full text).
- ^ Joseph R. Masiero et al .: Main belt asteroids with WISE / NEOWISE. I. Preliminary albedos and diameters (November 2011, PDF). (PDF) Retrieved September 10, 2017 .
- ↑ Joseph R. Masiero et al .: Main-belt Asteroids with WISE / NEOWISE: Near-infrared Albedos . August 2014, bibcode : 2014ApJ ... 791..121M .
- ↑ DP Cruikshank: Organic Matter on Asteroid 130 Elektra . October 1987, bibcode : 1987Sci ... 238..183C .
- ^ Franck Marchis: Orbital Elements of S / 2003 (130) 1 (2005). (No longer available online.) Archived from the original on July 24, 2007 ; accessed on September 10, 2017 .
- ↑ Daniel WE Green: IAUC No. 8183: S / 2003 (130) 1 discovery publication. August 2003, accessed September 9, 2017 .
- ↑ Bin Yang et al .: Elektra: Ein neue Dreifachasteroid (2016). Retrieved September 10, 2017 .