| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 19 May 1919 |
| Designations | |
| (913) Otila | |
Named after | Name picked from the almanac Lahrer Hinkender Bote[2] |
| A919 KD · 1935 ES 1942 NB · 1955 LB A909 HD · 1909 HD 1919 FL | |
| Orbital characteristics[3] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 110.78yr (40,464 d) |
| Aphelion | 2.5728AU |
| Perihelion | 1.8219 AU |
| 2.1973 AU | |
| Eccentricity | 0.1709 |
| 3.26 yr (1,190 d) | |
| 329.43° | |
| 0° 18m 9.36s / day | |
| Inclination | 5.8059° |
| 94.928° | |
| 188.68° | |
| Physical characteristics | |
| 4.8720±0.0002 h[9] | |
| 12.0[1][3] | |
913 Otila (prov. designation:A919 KDor1919 FL) is a brightFlora asteroid from the inner regions of theasteroid belt. It was discovered by German astronomerKarl Reinmuth at theHeidelberg Observatory on 19 May 1919.[1] The stonyS-type asteroid has a shortrotation 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 almanacLahrer Hinkender Bote.[12]
When applying the synthetichierarchical clustering method (HCM) byNesvorný,[4] or the 1995 HCM-analysis byZappalà,[5]Otila is a member of theFlora family (402), a giantasteroid family and the largest family of stony asteroids in the main-belt.[13]: 23 However, according to another HCM-analysis byMilani andKnežević (AstDys), it is abackground asteroid as this analysis does not recognize the Floraasteroid clan.[6]Otila orbits the Sun in theinner 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 aneccentricity of 0.17 and aninclination of 6° with respect to theecliptic.[3] The body'sobservation arc begins with its first observation asA909 HD (1909 HD) atHeidelberg Observatory in April 1909, more than 10 year prior to its official discovery observation.[1]
Thisminor planet was named "Otila", after a female name picked from theLahrer Hinkender Bote, published inLahr, southern Germany.[2] AHinkender Bote (lit. "limping messenger") was a very popularalmanac,[12] especially in thealemannic-speaking region from the late 17th throughout the early 20th century. Thecalendar section containsfeast days, the dates of important fairs andastronomical ephemerides. For 26 February, the calendar gives "Otila" as the Germanname day analogue next toHestor andAlexander, the protestant and catholic entries in thecalendar of saints, latter likely referring toPope Alexander I of Alexandria, whose feast day is also 26 February.[14]
Otila is the first in a series of 23 asteroids – ending with1144 Oda – for which Reinmuth used theLahrer 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 theDictionary of Minor Planet Names learned about Reinmuth's source of inspiration from private communications with Dutch astronomerIngrid van Houten-Groeneveld, who worked as a young astronomer at Heidelberg.[2]
In the Bus–BinzelSMASS classification,Otila is an Sa-subtype that transitions from a common, stonyS-type to an uncommonA-type asteroid,[3] 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).[10][11]
In April 2007, a rotationallightcurve ofOtila was obtained fromphotometric observations byJulian Oey. Lightcurve analysis gave arotation period of4.8720±0.0002 hours with a brightness amplitude of0.22±0.02magnitude (U=3).[9]
According to the survey carried out by the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE),Otila measures (11.32±0.45) and (11.636±0.240) kilometers in diameter and its surface has analbedo of (0.245±0.021) and (0.282±0.057), respectively.[7][8] TheCollaborative 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 anabsolute magnitude of 12.0.[15] Other publications by the WISE team give amean 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).[10][15]
