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 byE. F. Helin
S. J. Bus
Discovery sitePalomar Obs.
Discovery date7 November 1978
Designations
(2324) Janice
Named after
Janice Cline [1]
(Supporter at Caltech)
1978 VS4 · 1929 WH
1934 VR · 1949 ME
1961 UP · 1971 OC1
1975 EM2 · 1977 RY4
A911 MC
main-belt [1][2] · (outer)
background [3] · Themis [4][5]
Orbital characteristics [2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc83.28 yr (30,418 d)
Aphelion3.6382 AU
Perihelion2.5282 AU
3.0832 AU
Eccentricity0.1800
5.41 yr (1,977 d)
245.72°
0° 10m 55.56s / day
Inclination0.3995°
315.66°
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]
23.2±0.1 h[11]
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]
C (assumed)[4]
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]

    References
    1. "2324 Janice (1978 VS4)". Minor Planet Center. Retrieved 26 March 2018.
    2. "JPL Small-Body Database Browser: 2324 Janice (1978 VS4)" (2018-02-25 last obs.). Jet Propulsion Laboratory. Retrieved 26 March 2018.
    3. "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Archived from the original on 2 August 2017. Retrieved 26 March 2018.
    4. "LCDB Data for (2324) Janice". Asteroid Lightcurve Database (LCDB). Retrieved 26 March 2018.
    5. "Asteroid 2324 Janice – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 29 October 2019.
    6. Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63.
    7. Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. Retrieved 17 October 2019. (online, AcuA catalog p. 153)
    8. Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117.
    9. Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90.
    10. Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68.
    11. Gartrelle, Gordon M. (April 2012). "Lightcurve Results for Eleven Asteroids". The Minor Planet Bulletin. 39 (2): 40–46. Bibcode:2012MPBu...39...40G. ISSN 1052-8091.
    12. Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8.
    13. Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007.
    14. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 26 March 2018.

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