_Adele.png) Modelled shape ofAdele from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | S. Belyavskyj |
| Discovery site | Simeiz Obs. |
| Discovery date | 8 September 1915 |
| Designations | |
| (812) Adele | |
Named after | Adele, character in the operettaDie Fledermaus[2] |
| A915 RU · A902 UE 1915 XV | |
| Orbital characteristics[3] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 104.40yr (38,132 d) |
| Aphelion | 3.0981AU |
| Perihelion | 2.2220 AU |
| 2.6601 AU | |
| Eccentricity | 0.1647 |
| 4.34 yr (1,585 d) | |
| 46.769° | |
| 0° 13m 37.92s / day | |
| Inclination | 13.298° |
| 7.2582° | |
| 353.10° | |
| Physical characteristics | |
| 5.8587±0.0002 h[9] | |
| S(family-based)[10][11] | |
812 Adele (prov. designation:A915 RUor1915 XV) is an elongatedEunomia asteroid from the central regions of theasteroid belt. It was discovered on 8 September 1915, by Russian astronomerSergey Belyavsky at theSimeiz Observatory on the Crimean peninsula.[1] The presumedS-type asteroid has arotation period of 5.9 hours and measures approximately 13 kilometers (8 miles) in diameter. It was likely named after the character "Adele" in the operaDie Fledermaus byJohann Strauss.[2]
When applying thehierarchical clustering method to itsproper orbital elements,Adele is a core member of theEunomia family (502),[4][5][6] a prominentfamily of stonyS-type asteroids and the largest one in the intermediate main belt with more than 5,000 known members.[11]: 23 It orbits the Sun in thecentral asteroid belt at a distance of 2.2–3.1 AU once every 4 years and 4 months (1,585 days;semi-major axis of 2.66 AU). Its orbit has aneccentricity of 0.16 and aninclination of 13° with respect to theecliptic.[3]
Adele was discovered by Russian astronomerSergey Belyavsky at theSimeiz Observatory on the Crimean peninsula 8 September 1915. Three nights later, on 11 September 1915, it was independently discovered byMax Wolf theHeidelberg Observatory in Germany. TheMinor Planet Center however, only credits the first discoverer. The asteroid was first observed asA902 UE at Heidelberg on 25 October 1902. The body'sobservation arc begins at theBergedorf Observatory on 19 September 1915, less than two weeks after its official discovery observation.[1]
Thisminor planet was likely named after "Adele", Rosalinde's maid, a character in the operettaDie Fledermaus byJohann Strauss (1825–1899). The name was given by the independent discoverer Max Wolf. The author of theDictionary of Minor Planet Names,Lutz Schmadel, learned about the meaning of the asteroid's name from R. Bremer andIngrid van Houten-Groeneveld, latter who worked as a young astronomer at Heidelberg.
Based on the overallspectral type of the Eunomia family,[11]: 23 Adele is likely a common, stonyS-type asteroid.[10]
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In October 2002, a rotationallightcurve ofAdele was obtained fromphotometric observations by French amateur astronomerRené Roy. Lightcurve analysis gave a well-definedrotation period of5.8587±0.0002 hours with a high brightness variation of0.69±0.02magnitude, indicative of an elongated shape (U=3).[9]
In 2016, a modeled lightcurve gave a concurring sidereal period of5.85746±0.00002 hours using data from the Uppsala Asteroid Photometric Catalogue, thePalomar Transient Factory survey, and individual observers (such as above), as well as sparse-in-time photometry from theNOFS, theCatalina Sky Survey, and the La Palma surveys (950). The study also determined twospin axes at (301.0°, 44.0°) and (154.0°, 69.0°) inecliptic coordinates (λ, β).[12]
According to the surveys carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE) and the JapaneseAkari satellite,Adele measures (12.356±0.111) and (13.57±0.43) kilometers in diameter and its surface has analbedo of (0.291±0.041) and (0.257±0.019), respectively.[7][8] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for a Eunomian asteroid of 0.21 and calculates a diameter of 12.66 kilometers based on anabsolute magnitude of 11.8.[10] Alternative mean-diameter measurements published by the WISE team include (11.93±0.33 km) and (13.619±0.263 km) with corresponding albedos of (0.259±0.047) and (0.2420±0.0275).[5][10]
