822 Lalage

822 Lalage (prov. designation: A916 GJ or 1916 ZD) is a background asteroid from the inner regions of the asteroid belt. It was discovered on 31 March 1916, by astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory in southwest Germany.[1] The likely highly elongated asteroid with an unclear spectral type has a short rotation period of 3.3 hours and measures approximately 9 kilometers (5.6 miles) in diameter. Any reference to the origin of the asteroid's name is unknown.[3]

822 Lalage
Modelled shape of Lalage from its lightcurve
Discovery [1]
Discovered byM. F. Wolf
Discovery siteHeidelberg Obs.
Discovery date31 March 1916
Designations
(822) Lalage
Pronunciation/ˈlælədʒiː/[2]
Named after
unknown Lalage[3]
A916 GJ · 1943 EJ1
1916 ZD
Orbital characteristics [4]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc103.84 yr (37,929 d)
Aphelion2.6064 AU
Perihelion1.9043 AU
2.2554 AU
Eccentricity0.1556
3.39 yr (1,237 d)
342.25°
0° 17m 27.6s / day
Inclination0.7172°
210.11°
247.21°
Physical characteristics
Mean diameter
3.345±0.001 h[9]
  • (343.0°, −74.0°) (λ1/β1)[6]
  • (133.0°, −75.0°) (λ2/β2)[6]
  • 0.187±0.010[8]
  • 0.349±0.045[7]
12.1[1][4]

    Orbit and classification

    Lalage 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 1.9–2.6 AU once every 3 years and 5 months (1,237 days; semi-major axis of 2.26 AU). Its orbit has an eccentricity of 0.16 and an inclination of 1° with respect to the ecliptic.[4] The body's observation arc begins at the Bergedorf Observatory on 6 April 1916, one week after its official discovery observation at Heidelberg.[1]

    Naming

    Any reference of this minor planet's name to a person or occurrence is unknown.[3]

    Unknown meaning

    Among the many thousands of named minor planets, Lalage is one of 120 asteroids, for which no official naming citation has been published. All of these asteroids have low numbers, the first one being 164 Eva. The last asteroid with a name of unknown meaning is 1514 Ricouxa. They were discovered between 1876 and the 1930s, predominantly by astronomers Auguste Charlois, Johann Palisa, Max Wolf and Karl Reinmuth.[11]

    Physical characteristics

    In the Tholen classification, Lalage has an unusual spectrum, that is closest to a dark D-type, somewhat similar to an X-type, and, to a lesser extent, a carbonaceous C-type asteroid.[4] Conversely, the Small Solar System Objects Spectroscopic Survey (S3OS2), classifies the body an uncommon A-type in the survey's Tholen-like taxonomic variant, and as an Sl-subtype – which transitions from the stony S-type to the uncommon L-type asteroid – in its SMASS-like variant.[6][10]

    Rotation period

    In September 1992, a rotational lightcurve of Lalage was obtained from photometric observations by Polish astronomer Wiesław Wiśniewski. Lightcurve analysis gave a short rotation period of 3.345±0.001 hours with a high brightness variation of 0.47±0.02 magnitude, indicative of a non-spherical, elongated shape (U=3).[9] Since then, additional period determinations gave 3.3465±0.0006 hours with an amplitude of 0.58±0.01 magnitude (U=3) by David Higgins in October 2009,[12] 3.3460±0.0005 hours with an amplitude of 0.67±0.02 magnitude (U=3) by Robert Stephens in January 2014,[13] and 3.346±0.001 hours with an amplitude of 0.53±0.05 magnitude (U=3−) by Daniel A. Klinglesmith in February 2014.[14] A modeled lightcurves using photometric data from the BlueEye600 robotic telescope (L36) at Ondřejov Observatory gave a sidereal period of 3.346503±0.000002. The modelling also gave two poles at (343.0°, −74.0°) and (133.0°, −75.0°) in ecliptic coordinates (λ, β).[15]

    Diameter and albedo

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer and the Japanese Akari satellite, Lalage measures (8.243±0.336) and (11.34±0.28) kilometers in diameter and its surface has an albedo of (0.349±0.045) and (0.187±0.010), respectively.[7][8] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.20 and a diameter of 10.16 kilometers based on an absolute magnitude of 12.33.[16] The WISE team also published an alternative mean-diameter of (8.868±1.502 km) with an albedo of (0.361±0.137).[6]

    References
    1. "822 Lalage (A916 GJ)". Minor Planet Center. Retrieved 10 March 2020.
    2. Noah Webster (1884) A Practical Dictionary of the English Language
    3. Schmadel, Lutz D. (2007). "(822) Lalage". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 76. doi:10.1007/978-3-540-29925-7_823. ISBN 978-3-540-00238-3.
    4. "JPL Small-Body Database Browser: 822 Lalage (A916 GJ)" (2020-02-04 last obs.). Jet Propulsion Laboratory. Retrieved 10 March 2020.
    5. "Asteroid 822 Lalage – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 10 March 2020.
    6. "Asteroid 822 Lalage". Small Bodies Data Ferret. Retrieved 10 March 2020.
    7. Mainzer, A. K.; Bauer, J. M.; Cutri, R. M.; Grav, T.; Kramer, E. A.; Masiero, J. R.; et al. (June 2016). "NEOWISE Diameters and Albedos V1.0". NASA Planetary Data System. Bibcode:2016PDSS..247.....M. Retrieved 10 March 2020.
    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 10 March 2020. (online, AcuA catalog p. 153)
    9. Wisniewski, W. Z.; Michałowski, T. M.; Harris, A. W.; McMillan, R. S. (April 1997). "Photometric Observations of 125 Asteroids". Icarus. 126 (2): 395–449. Bibcode:1997Icar..126..395W. doi:10.1006/icar.1996.5665. ISSN 0019-1035.
    10. Lazzaro, D.; Angeli, C. A.; Carvano, J. M.; Mothé-Diniz, T.; Duffard, R.; Florczak, M. (November 2004). "S3OS2: the visible spectroscopic survey of 820 asteroids" (PDF). Icarus. 172 (1): 179–220. Bibcode:2004Icar..172..179L. doi:10.1016/j.icarus.2004.06.006. Retrieved 10 March 2020.
    11. 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.
    12. Higgins, David (January 2011). "Period Determination of Asteroid Targets Observed at Hunters Hill Observatory: May 2009 - September 2010" (PDF). Minor Planet Bulletin. 38 (1): 41–46. Bibcode:2011MPBu...38...41H. ISSN 1052-8091.
    13. Stephens, Robert D. (July 2014). "Asteroids Observed from CS3: 2014 January - March" (PDF). Minor Planet Bulletin. 41 (3): 171–175. Bibcode:2014MPBu...41..171S. ISSN 1052-8091.
    14. Klinglesmith, Daniel A., III; Hanowell, Jesse; Risley, Ethan; Turk, Janek; Vargas, Angelica; Warren, Curtis Alan (July 2014). "Lightcurves for Inversion Model Candidates" (PDF). Minor Planet Bulletin. 41 (3): 139–143. Bibcode:2014MPBu...41..139K. ISSN 1052-8091.
    15. Ďurech, Josef; Hanuš, Josef; Brož, Miroslav; Lehký, Martin; Behrend, Raoul; Antonini, Pierre; et al. (April 2018). "Shape models of asteroids based on lightcurve observations with BlueEye600 robotic observatory". Icarus. 304: 101–109. arXiv:1707.03637. Bibcode:2018Icar..304..101D. doi:10.1016/j.icarus.2017.07.005. ISSN 0019-1035.
    16. "LCDB Data for (822) Lalage". Asteroid Lightcurve Database (LCDB). Retrieved 10 March 2020.
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