(130) Electra

Asteroid (130) Electra
Properties of the orbit ( animation ) Epoch: 4th September 2017 ( JD 2,458,000.5)
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

Elektra in a 3D model

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 .

**Provisions of the diameter for Elektra**
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

Elektra with both moons

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 48730000 ♠1873
S / 2014 (130) 1 (Elektra II)	5.2	2.9	?	460	1,100	0.10	46.0	December 6, 2014 50141216 ♠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 50030817 ♠August 17, 2003

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 .

[JPL-1] (130) Elektra in the Small-Body Database of the Jet Propulsion Laboratory (English).

[durech-2] Joseph Ďurech et al .: Physical models of asteroids from ten to observers' collaboration network . April 2007, bibcode : 2007A & A ... 465..331D .

[tedesco-3] E. F. Tedesco et al .: IRAS Minor Planet Survey V6.0 . October 2006. bibcode : 2004PDSS ... 12 ..... T .

[marchis-4] Franck Marchis et al .: Shape, size and multiplicity of main-belt asteroids I. Keck Adaptive Optics survey . November 2006, PMC 2600456 (free full text).

[masiero-5] Joseph R. Masiero et al .: Main belt asteroids with WISE / NEOWISE. I. Preliminary albedos and diameters (November 2011, PDF). (PDF) Retrieved September 10, 2017 .

[masiero2-6] Joseph R. Masiero et al .: Main-belt Asteroids with WISE / NEOWISE: Near-infrared Albedos . August 2014, bibcode : 2014ApJ ... 791..121M .

[cruikshank-7] DP Cruikshank: Organic Matter on Asteroid 130 Elektra . October 1987, bibcode : 1987Sci ... 238..183C .

[marchis2-8] 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 .

[iauc8183-9] Daniel WE Green: IAUC No. 8183: S / 2003 (130) 1 discovery publication. August 2003, accessed September 9, 2017 .

[yang-10] Bin Yang et al .: Elektra: Ein neue Dreifachasteroid (2016). Retrieved September 10, 2017 .