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913 Otila (prov. designation: A919 KD or 1919 FL) is a bright Flora asteroid from the inner regions of the asteroid belt. It was discovered by German astronomer Karl Reinmuth at the Heidelberg Observatory on 19 May 1919. The stony S-type asteroid has a short rotation period of 4.9 hours and measures approximately 12 kilometers (7.5 miles) in diameter. It was named after a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

Orbit and classification

When applying the synthetic hierarchical clustering method (HCM) by Nesvorný, or the 1995 HCM-analysis by Zappalà, Otila is a member of the Flora family (402), a giant asteroid family and the largest family of stony asteroids in the main-belt. However, according to another HCM-analysis by Milani and Knežević (AstDys), it is a background asteroid as this analysis does not recognize the Flora asteroid clan. Otila orbits the Sun in the inner main-belt at a distance of 1.8–2.6 AU once every 3 years and 3 months (1,190 days; semi-major axis of 2.2 AU). Its orbit has an eccentricity of 0.17 and an inclination of 6° with respect to the ecliptic. The body's observation arc begins with its first observation as A909 HD (1909 HD) at Heidelberg Observatory in April 1909, more than 10 year prior to its official discovery observation.

Naming

This minor planet was named "Otila", after a female name picked from the Lahrer Hinkender Bote, published in Lahr, southern Germany. 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 days, the dates of important fairs and astronomical ephemerides. For 26 February, the calendar gives "Otila" as the German name day analogue next to Hestor and Alexander, the protestant and catholic entries in the calendar of saints, latter likely referring to Pope Alexander I of Alexandria, whose feast day is also 26 February.

Reinmuth's calendar names

Otila is the first in a series of 23 asteroids – ending with 1144 Oda – for which Reinmuth used the Lahrer Hinkender Bote to select names from, as he had trouble thinking of proper names due to his many asteroid discoveries. 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.

Physical characteristics

In the Bus–Binzel SMASS classification, Otila is an Sa-subtype that transitions from a common, stony S-type to an uncommon A-type asteroid, while in the Bus-DeMeo-taxonomy, it is an Sw-type asteroid, where the "w" notation is used for a objects with a high spectral slope (greater than 0.25).

Rotation period

In April 2007, a rotational lightcurve of Otila was obtained from photometric observations by Julian Oey. Lightcurve analysis gave a rotation period of 4.8720±0.0002 hours with a brightness amplitude of 0.22±0.02 magnitude (U=3).

Diameter and albedo

According to the survey carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), Otila measures (11.32±0.45) and (11.636±0.240) kilometers in diameter and its surface has an albedo of (0.245±0.021) and (0.282±0.057), respectively. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for members of the Flora family of 0.24 and calculates a diameter of 10.80 kilometers based on an absolute magnitude of 12.0. Other publications by the WISE team give a mean diameter of (9.452±1.432) and (12.264±0.069) kilometers with a corresponding albedo of (0.442±0.250) and (0.2056±0.0121).

References

1. ^ "913 Otila (A919 KD)". Minor Planet Center. Retrieved 23 February 2020.
2. ^ Schmadel, Lutz D. (2007). "(913) Otila". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 82. doi:10.1007/978-3-540-29925-7_914. ISBN 978-3-540-00238-3.
3. ^ "JPL Small-Body Database Browser: 913 Otila (A919 KD)" (2020-02-03 last obs.). Jet Propulsion Laboratory. Retrieved 23 February 2020.
4. ^ "Asteroid 913 Otila – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 23 February 2020.
5. ^ Zappalà, V.; Bendjoya, Ph.; Cellino, A.; Farinella, P.; Froeschle, C. (1997). "Asteroid Dynamical Families". NASA Planetary Data System: EAR-A-5-DDR-FAMILY-V4.1. Retrieved 15 March 2020.} (PDS main page)
6. ^ "Asteroid 913 Otila – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 23 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. ^ Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121.
9. ^ Oey, Julian; Krajewski, Ric (June 2008). "Lightcurve Analysis of Asteroids from Kingsgrove and Other Collaborating Observatories in the First Half of 2007" (PDF). Minor Planet Bulletin. 35 (2): 47–48. Bibcode:2008MPBu...35...47O. ISSN 1052-8091. Archived from the original (PDF) on 13 February 2020. Retrieved 23 February 2020.
10. ^ "Asteroid 913 Otila". Small Bodies Data Ferret. Retrieved 23 February 2020.
11. ^ DeMeo, Francesca E.; Binzel, Richard P.; Slivan, Stephen M.; Bus, Schelte J. (July 2009). "An extension of the Bus asteroid taxonomy into the near-infrared" (PDF). Icarus. 202 (1): 160–180. Bibcode:2009Icar..202..160D. doi:10.1016/j.icarus.2009.02.005. Archived from the original (PDF) on 17 March 2014. Retrieved 23 February 2020. (Catalog Archived 29 March 2018 at the Wayback Machine at PDS)
12. ^ "Lahrer hinkender Bote – Kalender 1925". Badischen Landesbibliothek. 1925. p. 1. Retrieved 18 February 2020. Lahrer Bote archive
13. Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families". Asteroids IV: 297–321. arXiv:1502.01628. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016.
14. "Lahrer hinkender Bote – Kalender 1925". Badischen Landesbibliothek. 1925. p. 4. Retrieved 18 February 2020.
15. ^ "LCDB Data for (913) Otila". Asteroid Lightcurve Database (LCDB). Retrieved 23 February 2020.

External links

• Do Slivan states exist in the Flora family?. I. Photometric survey of the Flora region, Astronomy & Astrophysics, A. Kryszczynska
• Lightcurve Database Query (LCDB), at www.minorplanet.info
• Dictionary of Minor Planet Names, Google books
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 913 Otila at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 913 Otila at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• Flora asteroids
• Discoveries by Karl Wilhelm Reinmuth
• Named minor planets
• Sa-type asteroids (SMASS)
• Astronomical objects discovered in 1919