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.[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. (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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