983 Gunila

983 Gunila (prov. designation: A922 OD or 1922 ME), is a dark background asteroid from the outer regions of the asteroid belt, approximately 74 kilometers (46 miles) in diameter. It was discovered on 30 July 1922, by astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in Germany.[1] The X-type asteroid has an ambiguous rotation period of 8.3 or 16.6 hours. It was named "Gunila", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.[2]

983 Gunila
Discovery [1]
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date30 July 1922
Designations
(983) Gunila
Named after
Name picked from the almanac
Lahrer Hinkender Bote [2]
A922 OD · 1934 SE
1940 TF · 1944 LA
1949 JB · 1955 HV
1922 ME · 1949 JB
main-belt [1][3] · (outer)
background [4][5]
Orbital characteristics [3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc97.43 yr (35,585 d)
Aphelion3.4513 AU
Perihelion2.8707 AU
3.1610 AU
Eccentricity0.0919
5.62 yr (2,053 d)
209.40°
0° 10m 31.44s / day
Inclination14.868°
250.70°
348.40°
Physical characteristics
Mean diameter
  • 73.87±1.3 km[6]
  • 92.90±1.44 km[7]
  • 95.689±1.941 km[8]
8.37±0.12 h[9]
  • 0.028±0.010[8]
  • 0.0477±0.002[6]
  • 0.031±0.001[7]
9.4[1][3]

    Orbit and classification

    Gunila is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.[4][5] It orbits the Sun in the outer asteroid belt at a distance of 2.9–3.5 AU once every 5 years and 7 months (2,053 days; semi-major axis of 3.16 AU). Its orbit has an eccentricity of 0.09 and an inclination of 15° with respect to the ecliptic.[3] The body's observation arc begins at the Vienna Observatory on 21 August 1922, or three weeks after its official discovery observation at Heidelberg.[1]

    Naming

    This minor planet was named "Gunila", after a female name picked from the Lahrer Hinkender Bote,[11] published in Lahr, southern Germany.[2] A Hinkender Bote (lit. "limping messenger") was a very popular almanac, especially in the alemannic-speaking region from the late 17th throughout the early 20th century. The calendar section contains feast/name days, the dates of important fairs and astronomical ephemerides. For 9 November, the calendar gives "Gunila" as the German analogue for Theodor and Erbo, the respective Catholic and Protestant feast-days. Former is likely related to Saint Theodore of Amasea (died 306), whose feast day is also 9 November.[12]

    Reinmuth's calendar names

    As with 22 other asteroids – starting with 913 Otila, and ending with 1144 Oda – Reinmuth selected names from this calendar due to his many asteroid discoveries that he had trouble thinking of proper names. These names are not related to the discoverer's contemporaries. Lutz Schmadel, the author of the Dictionary of Minor Planet Names learned about Reinmuth's source of inspiration from private communications with Dutch astronomer Ingrid van Houten-Groeneveld, who worked as a young astronomer at Heidelberg.[2]

    Physical characteristics

    In the Tholen classification, Gunila is an X-type asteroid, and somewhat similar to that of a dark D-type (XD).[3] In the Tholen-like taxonomy of the Small Solar System Objects Spectroscopic Survey (S3OS2), the asteroid is also an X-type, while in the S3OS2-survey's SMASS-like taxonomy it is an Xk-subtype that transitions to the K-type asteroids.[5][10]

    Rotation period

    In October 2013, a rotational lightcurve of Gunila was obtained from photometric observations by the ASTR315 class at the University of Maryland. Lightcurve analysis gave an ambiguous rotation period of 8.37±0.12 hours with a low brightness variation of 0.11±0.01 magnitude (U=2), indicative of a rather spherical shape.[9] An alternative period determination by Tom Polakis in 2018 gave 16.633±0.023 hours (or twice the period), also with a low amplitude of 0.12±0.02 magnitude (U=2).[13] In September 2001, an unsuccessful attempt to measure the asteroid's period was made by Brian Warner at the Palmer Divide Observatory in Colorado (U=n.a.).[13][lower-alpha 1]

    Diameter and albedo

    According to the survey carried out by the Infrared Astronomical Satellite IRAS, Gunila measures 73.87±1.3 kilometers (km) in diameter and its surface has an albedo of 0.0477±0.002.[6] The Japanese Akari satellite gave a larger diameter of 92.90±1.44 km and an albedo of 0.031±0.001,[7] as did various publications of the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, with diameters of 95.689±1.941 km or larger.[8][13] The Collaborative Asteroid Lightcurve Link adopts the results from IRAS, and gives a diameter of 73.87 km with an albedo of 0.0477 based on an absolute magnitude of 9.58.[13]

    Three asteroid occultations between 2006 and 2014, gave an estimated diameter of 74, 92 and 93 kilometers, respectively.[5] These timed observations are taken when the asteroid passes in front of a distant star. However the measurements for Gunila were of poor quality in all three cases.[5]

    Notes
    1. Lightcurve plot of (983) Gunila, Palmer Divide Observatory, B. D. Warner (2001) rotation period undetermined with little to no brightness amplitude. Quality code of n.a. The asteroid might have very long period or it could have short period with a lightcurve that shows no amplitude. Summary figures at the LCDB

    References
    1. "983 Gunila (A922 OD)". Minor Planet Center. Retrieved 10 February 2020.
    2. Schmadel, Lutz D. (2007). "(983) Gunila". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 85. doi:10.1007/978-3-540-29925-7_984. ISBN 978-3-540-00238-3.
    3. "JPL Small-Body Database Browser: 983 Gunila (A922 OD)" (2020-01-03 last obs.). Jet Propulsion Laboratory. Retrieved 10 February 2020.
    4. "Asteroid 983 Gunila – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 10 February 2020.
    5. "Asteroid 983 Gunila – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 10 February 2020.
    6. 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 10 February 2020.
    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. (online, AcuA catalog p. 153)
    8. 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 February 2020.
    9. Hayes-Gehrke, Melissa; Berenhaus, Joshua; Mascone, Anthony; Lopez-Lahocki, Michael; Levantis, George; Haigh, Evan; et al. (April 2014). "Rotation Period of 983 Gunila". The Minor Planet Bulletin. 41 (2): 77. Bibcode:2014MPBu...41...77H.
    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 February 2020.
    11. "Lahrer hinkender Bote – Kalender 1925". Badischen Landesbibliothek. 1925. p. 1. Retrieved 10 February 2020. Lahrer Bote collection
    12. "Lahrer hinkender Bote – Kalender 1925". Badischen Landesbibliothek. 1925. p. 22. Retrieved 10 February 2020.
    13. "LCDB Data for (983) Gunila". Asteroid Lightcurve Database (LCDB). Retrieved 10 February 2020.
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