60 Echo

60 Echo
	Three-dimensional model of 60 Echo created based on light-curve
Discovery
Discovered by	James Ferguson
Discovery date	September 14, 1860
Designations
MPC designation	(60) Echo
Pronunciation	/ˈɛkoʊ/
Named after	Echo
Minor planet category	Main belt
Adjectives	Echoian /ɛˈkoʊ.iən/
Orbital characteristics
	Epoch December 31, 2006 (JD 2454100.5)
Aphelion	2.830 AU (423.4 Gm)
Perihelion	1.958 AU (292.9 Gm)
Semi-major axis	2.394 AU (358.1 Gm)
Eccentricity	0.182
Orbital period (sidereal)	1,353.002 d (3.70 yr)
Mean anomaly	91.065°
Inclination	3.602°
Longitude of ascending node	191.803°
Argument of perihelion	270.477°
Physical characteristics
Dimensions	60.2 km
Mass	(3.15 ± 0.32) × 1017 kg
Mean density	2.78 ± 0.33 g/cm3
Synodic rotation period	25.2 hr
Geometric albedo	0.254
Spectral type	S
Absolute magnitude (H)	8.21

Echo (minor planet designation: 60 Echo) is a quite large main-belt asteroid. It was discovered by James Ferguson of the United States Naval Observatory in Washington D.C., on September 14, 1860. It was his third and final asteroid discovery. It is named after Echo, a nymph in Greek mythology. James Ferguson had initially named it "Titania", not realizing that name was already used for a satellite of Uranus.^[4]

This object is orbiting the Sun with a period of 3.70 years, a semimajor axis of 2.394 AU, and an eccentricity of 0.18. Its orbital plane is at an inclination of 3.6° to the plane of the ecliptic. This is a stony S-type asteroid with a cross-sectional size of 60.2 km that is spinning with a rotation period of 25.2 hr.^[1] Echo has been studied by radar.^[5] It is not known to be a member of any asteroid family.^[6]

References[edit]

^ ^a ^b ^c ^d ^e ^f "JPL Small-Body Database Browser: 60 Echo". Jet Propulsion Laboratory. 2011-08-14 last obs. Retrieved 27 January 2012.
^ ^a ^b Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
^ "Asteroid Data Sets". Archived from the original on 17 December 2009. Retrieved 12 January 2007.
^ Appletons' annual cyclopaedia and register of important events of the year: 1862. New York: D. Appleton & Company. 1863. p. 173.
^ "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. Retrieved 23 January 2012.
^ Carruba, V.; Aljbaae, S.; Winter, O. C. (January 2016), "On the Erigone family and the z2 secular resonance", Monthly Notices of the Royal Astronomical Society, 455 (3): 2279–2288, arXiv:1510.05551, Bibcode:2016MNRAS.455.2279C, doi:10.1093/mnras/stv2430