1704 Wachmann

1704 Wachmann, provisional designation A924 EE, is a stony asteroid from the inner regions of the asteroid belt, approximately 7 kilometers in diameter. It was discovered by German astronomer Karl Reinmuth at Heidelberg Observatory on 7 March 1924. It was later named after astronomer Arno Wachmann.^[2][8]

1704 Wachmann

Light curve based 3D-model of Wachmann
Discovery[1]
Discovered by	K. Reinmuth
Discovery site	Heidelberg Obs.
Discovery date	7 March 1924
Designations
MPC designation	(1704) Wachmann
Named after	Arno Wachmann (German astronomer)[2]
Alternative designations	A924 EE · 1947 CE 1957 BJ
Minor planet category	main-belt · (inner)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	93.16 yr (34,026 days)
Aphelion	2.4163 AU
Perihelion	2.0292 AU
Semi-major axis	2.2228 AU
Eccentricity	0.0871
Orbital period (sidereal)	3.31 yr (1,210 days)
Mean anomaly	67.047°
Mean motion	0° 17m 50.64s / day
Inclination	0.9715°
Longitude of ascending node	259.47°
Argument of perihelion	280.77°
Physical characteristics
Dimensions	6.618±0.070[4] 6.934±0.070 km[5] 7.82 km (calculated)[3]
Synodic rotation period	3.314±0.001 h[6]
Geometric albedo	0.1767±0.0133[5] 0.193±0.036[4] 0.20 (assumed)[3]
Spectral type	S[3]
Absolute magnitude (H)	12.9[1][3] · 12.97±0.13[7] · 13.3[5]

Classification and orbit

The S-type asteroid orbits the Sun in the inner main-belt at a distance of 2.0–2.4 AU once every 3 years and 4 months (1,210 days). Its orbit has an eccentricity of 0.09 and an inclination of 1° with respect to the ecliptic.^[1] No precoveries were taken. The asteroid's observation arc begins 3 days after its official discovery observation.^[8]

Physical characteristics

Lightcurves

In April 2007, a rotational lightcurve Wachmann was obtained at the U.S. Sandia View Observatory in New Mexico (H03). Lightcurve analysis gave a well-defined rotation period of 3.314±0.001 hours with a brightness variation of 0.40 magnitude (U=3).^[6]

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Wachmann measures 6.6 and 6.9 kilometers in diameter, and its surface has an albedo of 0.177 and 0.193, respectively,^[4][5] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 7.8 kilometers, based on an absolute magnitude of 12.9.^[3]

Naming

This minor planet was named for Arno Wachmann (1902–1990), long-time astronomer at the Bergedorf Observatory in Hamburg, discoverer of minor planets and comets, and observer of variable and binary stars. He is best known for the co-discovery of the three "Schwassmann–Wachmann" comets, 29P, 31P and 73P.^[2] The official naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3933).^[9]