82 Alkmene

82 Alkmene

A three-dimensional model of 82 Alkmene based on its light curve.
Discovery
Discovered by	Karl Theodor Robert Luther
Discovery date	November 27, 1864
Designations
Named after	Alcmene
Alternative names
Minor planet category	Main belt
Orbital characteristics
Epoch 2014-Dec-09 (JD 2457000.5)
Aphelion	3.3701 AU
Perihelion	2.1609 AU
Semi-major axis	2.7655 AU
Eccentricity	0.2186
Orbital period	4.60 yr
Average orbital speed	17.70 km/s
Mean anomaly	192.56°
Inclination	2.8286°
Longitude of ascending node	25.507°
Argument of perihelion	111.27°
Physical characteristics
Dimensions	61 ± 1.5 km (IRAS)
Mass	2.4×1017 kg (assumed)
Mean density	? g/cm³
Surface gravity	0.0170 m/s² (assumed)
Escape velocity	0.0322 km/s (assumed)
Rotation period	12.999 h
Albedo	0.208
Temperature	~168 K
Spectral type	S
Absolute magnitude (H)	8.40

82 Alkmene (/ælkˈmiːniː/ alk-MEE-nee) is a main-belt asteroid. Alkmene was discovered by R. Luther on November 27, 1864, and named after Alcmene, the mother of Herakles in Greek mythology. Based on IRAS data, Alkmene is estimated to be about 61 km in diameter. A satellite has been suggested based on 1985 lightcurve data.

Asteroid Alkmene occulted the apparent magnitude 7.5 star HIP 99229 in the constellation of Capricornus on 18 September 2014 around 06:41 UT (17 September 23:41 PDT) and was centered on Sacramento, CA. Alkmene projected an eclipse shadow that moves at about 2 miles/second. Asteroid occultations allow for accurate 2-dimensional mapping of an asteroids silhouette when observed by multiple telescopes separated by about 10km.