2324 Janice

2324 Janice, provisional designation 1978 VS₄, is a dark background asteroid from the outer regions of the asteroid belt, approximately 25 kilometers (16 miles) in diameter. It was discovered on 7 November 1978, by American astronomers Eleanor Helin and Schelte Bus at the Palomar Observatory in California.^[1] The asteroid was named for Janice Cline at Caltech. The presumably C-type asteroid has a rotation period of 23.2 hours.^[4]

2324 Janice

Discovery[1]
Discovered by	E. F. Helin S. J. Bus
Discovery site	Palomar Obs.
Discovery date	7 November 1978
Designations
MPC designation	(2324) Janice
Named after	Janice Cline [1] (Supporter at Caltech)
Alternative designations	1978 VS4 · 1929 WH 1934 VR · 1949 ME 1961 UP · 1971 OC1 1975 EM2 · 1977 RY4 A911 MC
Minor planet category	main-belt[1][2] · (outer) background[3] · Themis[4][5]
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc	83.28 yr (30,418 d)
Aphelion	3.6382 AU
Perihelion	2.5282 AU
Semi-major axis	3.0832 AU
Eccentricity	0.1800
Orbital period (sidereal)	5.41 yr (1,977 d)
Mean anomaly	245.72°
Mean motion	0° 10m 55.56s / day
Inclination	0.3995°
Longitude of ascending node	315.66°
Argument of perihelion	305.63°
Physical characteristics
Mean diameter	23.55 km (calculated)[4] 24.33±6.61 km[6] 24.44±1.22 km[7] 25.76±7.43 km[8] 28.463±0.354 km[9] 28.532±0.238 km[10] 28.9±15.91 km[11] 31.19±15.91 km[12]
Synodic rotation period	23.2±0.1 h[11]
Geometric albedo	0.038±0.004[10] 0.050±0.040[12] 0.06±0.04[6] 0.0601±0.0049[9] 0.07±0.03[8] 0.08 (assumed)[4] 0.093±0.010[7]
Spectral type	C (assumed)[4]
Absolute magnitude (H)	11.30[7] · 11.40[8][9][12] 11.46±0.36[13] · 11.5[2][4] 11.68[6]

Orbit and classification

Based on osculating Keplerian orbital elements, Janice is located in the region of the Themis family (602), a very large family of carbonaceous asteroids, named after 24 Themis.^[4]

When applying the hierarchical clustering method to its proper orbital elements, the object is both a non-family asteroid of the main belt's background population (according to Nesvorný),^[3] as well as a core member of the Themis family (according to Milani and Knežević).^[5]

It orbits the Sun in the outer main-belt at a distance of 2.5–3.6 AU once every 5 years and 5 months (1,977 days; semi-major axis of 3.08 AU). Its orbit has an eccentricity of 0.18 and an inclination of 0° with respect to the ecliptic.^[2] The body's observation arc begins with its first observation as A911 MC at Lowell Observatory in June 1911, more than 67 years prior to its official discovery observation at Palomar.^[1]

Physical characteristics

Janice is a presumed carbonaceous C-type asteroid which is the overall spectral type of members of the Themis family (602).^[4]

Rotation period

In October 2010, a rotational lightcurve of Janice was obtained from photometric observations by Gordon Gartrelle at the University of North Dakota Observatory in Grand Forks (730). Lightcurve analysis gave a tentative rotation period of 23.2 hours with a brightness amplitude of 0.19 magnitude (U=2-).^[11] As of 2018, no secure period has been obtained.^[4]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Janice measures between 24.33 and 31.19 kilometers in diameter and its surface has an albedo between 0.038 and 0.093.^{[6][7][8][9][10][12]}

The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.08 and calculates a diameter of 23.55 kilometers based on an absolute magnitude of 11.5.^[4]

Naming

This minor planet was named after Janice Cline, who for many years has encouraged astrometric studies of minor planets at Caltech.^[1] The official naming citation was published by the Minor Planet Center on 1 March 1981 (M.P.C. 5850).^[14]