130 Elektra


Elektra is a large outer main-belt asteroid. It was discovered on 17 February 1873, by astronomer Christian Peters at Litchfield Observatory, New York, and named after Electra, an avenger in Greek mythology.

Description

The spectrum of 130 Elektra is of the G type; hence it probably has a Ceres-like composition. Spectral signatures of organic compounds have been seen on Elektra's surface and it displays evidence of aqueous alteration.
In the late 1990s, a network of astronomers worldwide gathered lightcurve data that was ultimately used to derive the spin states and shape models of 10 new asteroids, including Elektra. The light curve of Elektra forms a double sinusoid while the shape model is elongated and the derived rotation axis is perpendicular to the plane of the ecliptic.
Optical observations have found two satellites of this asteroid. Once the orbits are known, Elektra's mass can be reliably found. The value of 6.6 kg indicates a density of 1.3 ± 0.3 g/cm3. Optical observations have also determined that Elektra's shape is quite irregular, as well as giving indications of albedo differences of 5-15% on its surface.

Occultations

Elektra has been observed to pass in front of a dozen stars since 2007, most notably on April 21, 2018 when over 30 mostly citizen astronomers spread across five European countries recorded the sudden drop in light of an 11th magnitude star. The sky-plane plot of the chords reveals a peanut-shaped body, possibly the result of a two-body merger early in the history of the Solar System.

Satellites

In 2003, a small moon of Elektra was detected using the Keck II telescope. The diameter of the satellite is 4 km and it orbits at a distance of about 1170 km. It was given the provisional designation. Due to only a few observations to date, its orbit is still relatively loosely constrained.
In December 2014 a smaller inner moon, about 2 km across and orbiting Elektra about three times closer than S/2003 1, was discovered using the SPHERE instrument on the VLT's Melipal telescope. It was provisionally named.