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1230 Riceia
	Shape model of Riceia from its lightcurve
Discovery
Discovered by	K. Reinmuth
Discovery site	Heidelberg Obs.
Discovery date	9 October 1931
Designations
MPC designation	(1230) Riceia
Pronunciation	/ˈraɪsiə/
Named after	Hugh Rice; (U.S. amateur astronomer)
Alternative designations	1931 TX1 · 1964 TS; 1964 UE · 1975 HH
Minor planet category	main-belt · (inner); background
Orbital characteristics
	Epoch 4 September 2017 (JD 2458000.5)
	Uncertainty parameter 0
Observation arc	86.13 yr (31,459 days)
Aphelion	3.0335 AU
Perihelion	2.1104 AU
Semi-major axis	2.5719 AU
Eccentricity	0.1795
Orbital period (sidereal)	4.12 yr (1,507 days)
Mean anomaly	288.81°
Mean motion	0° 14m 20.4s / day
Inclination	10.515°
Longitude of ascending node	200.55°
Argument of perihelion	185.25°
Physical characteristics
Dimensions	6.194±0.344 km; 7.46 km (calculated)
Synodic rotation period	6.67317±0.00001 h
Geometric albedo	0.20 (assumed); 0.318±0.037
Spectral type	S
Absolute magnitude (H)	12.90 · 13.0 · 13.11±0.22

1230 Riceia, provisional designation 1931 TX₁, is a stony background asteroid from the central regions of the asteroid belt, approximately 6 kilometers in diameter. It was discovered on 9 October 1931, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory.^[8] The asteroid was named after Hugh Rice, amateur astronomer of New York and director of the Museum of Natural Sciences.^[2]

Orbit and classification

Riceia is a non-family asteroid from the main belt's background population.^[4] It orbits the Sun in the central asteroid belt at a distance of 2.1–3.0 AU once every 4 years and 1 month (1,507 days; semi-major axis of 2.57 AU). Its orbit has an eccentricity of 0.18 and an inclination of 11° with respect to the ecliptic.^[1]

The body's observation arc begins at Heidelberg on 17 October 1931, or eight days after its official discovery observation.^[8]

Physical characteristics

Riceia has been characterized as a stony S-type asteroid by Pan-STARRS photometric survey.^[7]

Rotation period and pole

In 2016, a rotational lightcurve of Riceia was modeled from photometric data from the Lowell Photometric Database. Lightcurve analysis gave a sidereal rotation period of 6.67317 hours as well as a spin axis of (37.0°, −63.0°) in ecliptic coordinates (λ, β).^[6]

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Riceia measures 6.19 kilometers in diameter and its surface has a high albedo of 0.318.^[5] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 7.46 kilometers based on an absolute magnitude of 13.0.^[3]

Naming

This minor planet was named after American amateur astronomer Hugh Rice, director of the Museum of Natural Sciences (possibly AMNH).^[2] The naming was proposed by Irving Meyer and endorsed by German astronomer Gustav Stracke who mentioned on a postcard in February 1937, that his American college, Meyer, who himself did not discover any asteroids, requested the naming after the city of Rutherford, where a private observatory was located at the time.^[9]

The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 113).^[2]