# 130 Elektra

130 Elektra is a very big farther main belt asteroid. It was found by C. H. F. Peters on February 17, 1873 and named after Electra, an avenger in Greek mythology.

Its spectrum is of the G type, so it is probably made up like Ceres. Spectral signatures of organic compounds have been seen on Elektra's surface [1]

Recent optical sightings have found a moon (see below). Using its orbit, Elektra's mass can be found more correctly. The value of 1.3×1019 kg indicates an unusually high density (for asteroids) of 3.8 ± 0.3 g/cm³. Optical sightings have also determined that Elektra's shape is quite non-spherical, as well as giving indications of albedo differences of 5-15% on its surface[2].

## Moon (S/2003 (130) 1)

In 2003, a small moon of Elektra was detected using the Keck II telescope. The diameter of the moon is 4 km and it orbits at a distance of about 1170 km. The moon has been given the provisional designation S/2003 (130) 1. Due to only a few sightings to date, its orbit is still not well known [3]

S/2003 (130) 1
Discovery[4] and designation
Discovered by W. J. Merline, P. M. Tamblyn,
C. Dumas, L. M. Close,
C. R. Chapman, and F. Menard
Discovery time 15 August, 2003
Names
Group Main belt
Orbit[3]
Longest distance from the center of its orbital path
("semi-major axis")
1252 ± 30 km
How egg-shaped its orbit is
("eccentricity")
unknown, likely small
How long it takes to complete an orbit 3.92 ± 0.03 d
Average speed 23 m/s
Angle above the reference plane
("inclination")
uncertain
What it orbits 130 Elektra
Size and Other Qualities
Measures 6 ± 2 km [2]
Mass ~4×1014 kg [5]
Slowest speed able to escape into space
("escape velocity")
~ 4 m/s
True brightness
("absolute magnitude")
14.5[2]
130 Elektra
Discovery[6] and designation
Discovered by Christian Heinrich Friedrich Peters
Discovery time February 17, 1873
Names
Other names
Group Main belt
Orbit[7]
Reference date December 31, 2006 (JD 2454100.5)
Longest distance from the Sun 565.778 Gm (3.782 AU)
Shortest distance from the Sun 369.263 Gm (2.468 AU)
Longest distance from the center of its orbital path
("semi-major axis")
467.521 Gm (3.125 AU)
How egg-shaped its orbit is
("eccentricity")
0.210
How long it takes to complete an orbit 2017.954 d (5.52 a)
Average speed 16.66 km/s
Mean anomaly 225.604°
Angle above the reference plane
("inclination")
22.838°
Longitude of where it comes up through the reference plane 145.635°
Angle between its shortest distance from what it orbits around and where it comes up through the reference plane
("argument of periapsis")
234.753°
Natural things which orbit around it S/2003 (130) 1
Size and Other Qualities
Measures 215×155 ± 12 km[8][9][10][11]
Mass 1.28±0.10×1019 kg [12][13]
Average density 3.8 ± 0.3 g/cm³ [3]
Gravity at its surface 0.07 m/s²[14]
Slowest speed able to escape into space
("escape velocity")
0.13 km/s[14]
How long it takes to turn around one time
(in relation to the stars)
0.230103 d (5.52247 h)[2]
Angle at which it turns
(in relation to its orbit)
157°
Latitude above the ecliptic -88°[2]
Longitude around the ecliptic 68°
How much light it reflects 0.076 ± 0.011 [15]
Surface temp. Min. Avg. Max.
Kelvin ~157 251
Celsius -23°
Light-band group
("spectral type")
G [16]
True brightness
("absolute magnitude")
7.12 [9]

## References

1. D.P. Cruikshank and R.H. Brown (1987). "Organic Matter on Asteroid 130 Elektra". Science 238: 183.
2. 130 Elektra and S/2003 (130) 1, orbit data website maintained by F. Marchis. Archived 16 January 2010 at WebCite
3. Assuming a similar density to the primary.
4. Discovery Circumstances: Numbered Minor Planets, Minor Planet Centre Archived 20 June 2007 at WebCite
5. ASTORB orbital elements database, Lowell Observatory
6. Based in IRAS mean diameter of 182±12 km, a/b ratio of 1.4 as per the following references
7. Supplemental IRAS Minor Planet Survey Archived 17 January 2010 at WebCite
8. PDS node spin vector database (in particular, the synthetic compiled value of a/b=1.4). Archived 17 January 2010 at WebCite
9. (130) Elektra and S/2003 (130) 1, at Johnston's archive (maintained by W. R. Johnston). Archived 26 May 2011 at WebCite
10. 130 Elektra and S/2003 (130) 1, F. Marchis Archived 16 January 2010 at WebCite
11. Error estimate derived from consideration of $M \propto a^3/P^2$ and given errors in a and P. See propagation of uncertainty.
12. On the extremities of the long axis.
13. Supplemental IRAS minor planet survey Archived 17 January 2010 at WebCite
14. PDS node taxonomy database Archived 16 January 2010 at WebCite