53 Kalypso

53 Kalypso is a large and very dark main belt asteroid that was discovered by German astronomer Robert Luther on April 4, 1858, at Düsseldorf.^[1] It is named after Calypso, a sea nymph in Greek mythology, a name it shares with Calypso, a moon of Saturn.

53 Kalypso

Three-dimensional model of 53 Kalypso created based on light-curve.
Discovery[1]
Discovered by	Karl Theodor Robert Luther
Discovery date	4 April 1858
Designations
MPC designation	(53) Kalypso
Pronunciation	/kəˈlɪpsoʊ/[2]
Named after	Calypso
Minor planet category	Main belt
Adjectives	Kalypsonian /kælɪpˈsoʊniən/[3] Kalypsoian /kælɪpˈsoʊ.iən/
Orbital characteristics[4]
Epoch December 31, 2006 (JD 2454100.5)
Aphelion	471.807 Gm (3.154 AU)
Perihelion	311.998 Gm (2.086 AU)
Semi-major axis	391.903 Gm (2.620 AU)
Eccentricity	0.204
Orbital period (sidereal)	1548.736 d (4.24 a)
Mean anomaly	98.113°
Inclination	5.153°
Longitude of ascending node	143.813°
Argument of perihelion	312.330°
Physical characteristics
Dimensions	115.4 km[4]
Mass	(1.294 ± 0.520/0.412)×1018 kg[5]
Mean density	1.625 ± 0.653/0.517 g/cm3[5][a]
Synodic rotation period	9.036[6] h
Geometric albedo	0.040[4][7]
Absolute magnitude (H)	8.81[4]

The orbit of 53 Kalypso places it in a mean motion resonance with the planets Jupiter and Saturn. The computed Lyapunov time for this asteroid is 19,000 years, indicating that it occupies a chaotic orbit that will change randomly over time because of gravitational perturbations of the planets.^[8]

Photometric observations of this asteroid during 2005–06 gave a light curve with a period of 18.075 ± 0.005 hours and a brightness variation of 0.14 in magnitude.^[9] In 2009, a photometric study from a different viewing angle was performed at the Organ Mesa Observatory in Las Cruces, New Mexico, yielding a rotation period of 9.036 ± 0.001 with a brightness variation of 0.14 ± 0.02 magnitude. This is exactly half of the 2005–06 result. The author of the earlier study used additional data observation that favored the 9.036 hour period. The discrepancy was deemed a consequence of viewing the asteroid from different longitudes.^[6]

Kalypso has been studied by radar.^[10]

Notes

1. Assuming a diameter of 115 ± 10.324 km.