1761 Edmondson

1761 Edmondson, provisional designation 1952 FN, is a dark background asteroid from the outer regions of the asteroid belt, approximately 21 kilometers in diameter. It was discovered on 30 March 1952, by the Indiana Asteroid Program at Goethe Link Observatory, United States.^[7] It was named after astronomer Frank Edmondson.^[2]

1761 Edmondson

Discovery[1]
Discovered by	Indiana University (Indiana Asteroid Program)
Discovery site	Goethe Link Obs.
Discovery date	30 March 1952
Designations
MPC designation	(1761) Edmondson
Named after	Frank Edmondson (American astronomer)[2]
Alternative designations	1952 FN · 1940 BC 1950 XP · 1952 HT 1955 US · 1969 JK 1978 WY
Minor planet category	main-belt · background[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	64.74 yr (23,646 days)
Aphelion	3.9145 AU
Perihelion	2.4388 AU
Semi-major axis	3.1766 AU
Eccentricity	0.2323
Orbital period (sidereal)	5.66 yr (2,068 days)
Mean anomaly	282.49°
Mean motion	0° 10m 26.76s / day
Inclination	2.4636°
Longitude of ascending node	76.988°
Argument of perihelion	49.903°
Physical characteristics
Dimensions	20.51 km (calculated)[3] 21.94±0.94 km[4]
Synodic rotation period	4.208±0.002 h[5]
Geometric albedo	0.08 (assumed)[3] 0.102±0.009[4]
Spectral type	C[3]
Absolute magnitude (H)	11.40[4] · 11.8[1][3] · 12.06±0.33[6]

Orbit and classification

Edmondson is a background asteroid, located near the region occupied by the Themis family, a dynamical family of outer-belt asteroids with nearly coplanar ecliptical orbits. It orbits the Sun in the outer main-belt at a distance of 2.4–3.9 AU once every 5 years and 8 months (2,068 days). Its orbit has an eccentricity of 0.23 and an inclination of 2° with respect to the ecliptic.^[1]

It was first identified as 1940 BC at Konkoly Observatory in 1940. The body's observation arc begins with its identification as 1950 XP at McDonald Observatory in 1950, or 2 years prior to its official discovery observation at Goethe Link.^[7]

Physical characteristics

Edmondson has been characterized as a carbonaceous C-type asteroid.^[3]

Rotation period

In November 2012, a rotational lightcurve of Edmondson was obtained from photometric observations at the Etscorn Campus Observatory (719) in New Mexico, United States. Lightcurve analysis gave a well-defined rotation period of 4.208 hours with a brightness variation of 0.29 magnitude (U=3).^[5]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite, Edmondson measures 21.94 kilometers in diameter and its surface has an albedo of 0.102,^[4] while the Collaborative Asteroid Lightcurve Link assumes a more typical albedo for carbonaceous asteroids of 0.08 and calculates a diameter of 20.51 kilometers with an absolute magnitude of 11.8.^[3]

Naming

This minor planet was named for astronomer Frank K. Edmondson (1912–2008) of Indiana University, the program's founder and director.^[2] The official naming citation was published by the Minor Planet Center on 20 February 1971 (M.P.C. 3143).^[8]