_Auricula.png) Modelled shape ofAuricula from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 10 October 1931 |
| Designations | |
| (1231) Auricula | |
| Pronunciation | /ɔːˈrɪkjʊlə/[2] |
Named after | Primula auricula[3] (flowering plant) |
| 1931 TE2 | |
| main-belt[1][4] · (middle) background[5][6] | |
| Orbital characteristics[4] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 87.02yr (31,785 d) |
| Aphelion | 2.8988AU |
| Perihelion | 2.4388 AU |
| 2.6688 AU | |
| Eccentricity | 0.0862 |
| 4.36 yr (1,593 d) | |
| 171.27° | |
| 0° 13m 33.96s / day | |
| Inclination | 11.483° |
| 342.04° | |
| 245.60° | |
| Physical characteristics | |
| 13.43±4.67 km[7] 15.10±3.67 km[8] 18.71±0.65 km[9][10] 21.44±0.81 km[11] 22.52±1.8 km[12] | |
| 3.9816±0.0006 h[13] | |
| 0.066[9][10] 0.0798[12] 0.089[11] 0.11[8][7] | |
| C(SDSS-MOC)[14] | |
| 11.60[11] 12.2[1][4][8][9][10] 12.29[7] | |
1231 Auricula (prov. designation:1931 TE2) is a carbonaceous backgroundasteroid from the central regions of theasteroid belt, approximately 20 kilometers (12 miles) in diameter. It was discovered on 10 October 1931, by German astronomerKarl Reinmuth at theHeidelberg Observatory.[1] The likely elongatedC-type asteroid has arotation period of 3.98 hours.[15] It was named after the flowering plantauricula and indirectly honors astronomerGustav Stracke.[3]
Based on recentHCM-analyses,Auricula is a non-family asteroid that belongs to the main belt'sbackground population.[5][6] On its osculating Keplerianorbital elements, it is located in theEunomia region (502), where the prominent family ofstony asteroids is located.[15]
It orbits the Sun in thecentral main-belt at a distance of 2.4–2.9 AU once every 4 years and 4 months (1,593 days;semi-major axis of 2.67 AU). Its orbit has aneccentricity of 0.09 and aninclination of 11° with respect to theecliptic.[4] The body'sobservation arc begins with its official discovery observation atHeidelberg in October 1931.[1]
Thisminor planet was named after the yellow flowered Alpine primrose,primula auricula. The officialnaming citation was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 113).[3] It honors German astronomer and diligent orbit computerGustav Stracke (1887–1943), who had asked that no asteroid be named after him. The initials of the asteroids(1227) through (1234), all discovered byKarl Reinmuth, spell out "G. Stracke". In this manner, Reinmuth was able to circumvent Stracke's desire and honor him nevertheless. The asteroid1019 Strackea was later named after Stracke directly.[16] In the 1990s, astronomerBrian Marsden was also honored by this method, see asteroids5694 to5699. The consecutive initial letters of these minor-planet names spell out "MarsdenB".[17]
Due to his many discoveries,Karl Reinmuth submitted a large list of 66 newly named asteroids in the early 1930s. The list covered his discoveries with numbers between(1009) and(1200). This list also contained a sequence of 28 asteroids, starting with1054 Forsytia, that were all named after plants, in particularflowering plants(also see list of minor planets named after animals and plants).[18]
In theSDSS-based taxonomy,Auricula is a common, carbonaceousC-type asteroid.[5][14]
In April 2008, a rotationallightcurve ofAuricula was obtained fromphotometric observations by Colin Bembrick at the Mount Tarana Observatory (431) and other observers from Australia and New Zealand. Lightcurve analysis gave arotation period of3.9816±0.0006 hours with a brightness amplitude of 0.75magnitude (U=3), indicative of a non-spherical, elongated shape.[13] A modeled lightcurve using photometric data from the Lowell Photometric Database was published in 2016. It gave a concurring sidereal period of3.981580±0.000001 hours, as well as twospin axes at (57.0°, −57.0°) and (225.0°, −85.0°) inecliptic coordinates (λ, β).[19]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Auricula measures between 13.43 and 22.52 kilometers in diameter and its surface has analbedo between 0.066 and 0.11.[7][8][10][9][11][12] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.0465 and a diameter of 22.37 kilometers based on anabsolute magnitude of 12.2.[15]
