969 Leocadia

969 Leocadia (prov. designation: A921 VC or 1921 KZ) is a very dark background asteroid from the inner regions of the asteroid belt, approximately 19 kilometers (12 miles) in diameter. It was discovered on 5 November 1921, by Russian astronomer Sergey Belyavsky at the Simeiz Observatory on the Crimean peninsula.[1] The uncommon F-type asteroid (FX) has a rotation period of 6.9 hours and is likely regular in shape.[10] Any reference of the asteroid's name to a person is unknown.[3]

969 Leocadia
Discovery [1]
Discovered byS. Belyavskyj
Discovery siteSimeiz Obs.
Discovery date5 November 1921
Designations
(969) Leocadia
Pronunciation/liːoʊˈkeɪdiə/[2]
Named after
unknown [3]
A921 VC · 1940 RV
1944 SB · 1948 UG
1963 PA · 1921 KZ
main-belt [1][4] · (inner)
background [5][6]
Orbital characteristics [4]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc98.12 yr (35,837 d)
Aphelion2.9694 AU
Perihelion1.9537 AU
2.4615 AU
Eccentricity0.2063
3.86 yr (1,411 d)
199.53°
0° 15m 18.72s / day
Inclination2.2928°
287.76°
91.332°
Physical characteristics
Mean diameter
  • 17.321±0.218 km[7]
  • 19.37±0.22 km[8]
  • 19.51±0.7 km[9]
6.87±0.01 h[10][11]
  • 0.019±0.005[7]
  • 0.0435±0.003[9]
  • 0.045±0.001[8]
12.8[1][4]

    Orbit and classification

    Leocadia is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.[5][6] It orbits the Sun in the inner main-belt at a distance of 2.0–3.0 AU once every 3 years and 10 months (1,411 days; semi-major axis of 2.46 AU). Its orbit has an eccentricity of 0.21 and an inclination of 2° with respect to the ecliptic.[4] The body's observation arc begins at Uccle Observatory in February 1933, more than a decade after its official discovery observation Simeiz Observatory on 5 November 1921.[1]

    Naming

    This minor planet is named after a Feminine Russian first name. Any reference of this name to a person or occurrence is unknown.[3]

    Unknown meaning

    Among the many thousands of named minor planets, Leocadia is one of 120 asteroids, for which no official naming citation has been published. All of these low-numbered asteroids have numbers between 164 Eva and 1514 Ricouxa and were discovered between 1876 and the 1930s, predominantly by astronomers Auguste Charlois, Johann Palisa, Max Wolf and Karl Reinmuth (also see category).[12]

    Physical characteristics

    In the Tholen classification (FXU:), Leocadia is an uncommon and dark F-type asteroid, somewhat similar to that of an X-type, though with an unusual (U) and noisy (:) spectra.[4]

    Rotation period

    In December 2006, a rotational lightcurve of Leocadia was obtained from photometric observations by Italian amateur astronomers Roberto Crippa and Federico Manzini at the Sozzago Astronomical Station (A12). Lightcurve analysis gave a rotation period of 6.87±0.01 hours with a brightness amplitude of 0.14±0.01 magnitude (U=2), which is indicative of a rather spherical, non-irregular shape.[10][11]

    Diameter and albedo

    According to the surveys carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), the Japanese Akari satellite, and the Infrared Astronomical Satellite IRAS, Leocadia measures 17.321±0.218, 19.37±0.22 and 19.51±0.7 kilometers in diameter, and its surface has a very low albedo of 0.019±0.005, 0.0435±0.003 and 0.045±0.001, respectively.[7][8][9] Additional measurements by the WISE telescope were published giving a mean-diameter as low as 13.58±3.09 km.[11] The Collaborative Asteroid Lightcurve Link adopts the result from IRAS, that is, an albedo of 0.0435 and a diameter of 19.51 kilometers based on an absolute magnitude of 9.22.[11]

    An asteroid occultation on 19 August 2013, gave a best-fit ellipse dimension of 19.0 × 19.0 kilometers.[6] These timed observations are taken when the asteroid passes in front of a distant star. However the measurements for Leocadia were of poor quality.[6]

    References
    1. "969 Leocadia (A921 VC)". Minor Planet Center. Retrieved 11 February 2020.
    2. Noah Webster (1884) A Practical Dictionary of the English Language
    3. Schmadel, Lutz D. (2007). "(969) Leocadia". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 85. doi:10.1007/978-3-540-29925-7_970. ISBN 978-3-540-00238-3.
    4. "JPL Small-Body Database Browser: 969 Leocadia (A921 VC)" (2020-01-07 last obs.). Jet Propulsion Laboratory. Retrieved 11 February 2020.
    5. "Asteroid 969 Leocadia – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 11 February 2020.
    6. "Asteroid 969 Leocadia". Small Bodies Data Ferret. Retrieved 11 February 2020.
    7. 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.
    8. 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 11 February 2020. (online, AcuA catalog p. 153)
    9. Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 11 February 2020.
    10. Behrend, Raoul. "Asteroids and comets rotation curves – (969) Leocadia". Geneva Observatory. Retrieved 11 February 2020.
    11. "LCDB Data for (969) Leocadia". Asteroid Lightcurve Database (LCDB). Retrieved 11 February 2020.
    12. Schmadel, Lutz D. (2007). "Appendix 11 – Minor Planet Names with Unknown Meaning". Dictionary of Minor Planet Names – Fifth Revised and Enlarged revision. Springer Berlin Heidelberg. pp. 927–929. ISBN 978-3-540-00238-3.
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