_Rogeria.png) Modelled shape ofRogeria from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 1 September 1919 |
| Designations | |
| (920) Rogeria | |
Named after | Name picked from the almanac Lahrer Hinkender Bote[2][3] |
| A919 RC · 1919 FT 1973 QC | |
| main-belt[1][4] · (middle) background[5][6] | |
| Orbital characteristics[4] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 99.69yr (36,412 d) |
| Aphelion | 2.8993AU |
| Perihelion | 2.3476 AU |
| 2.6234 AU | |
| Eccentricity | 0.1051 |
| 4.25 yr (1,552 d) | |
| 162.25° | |
| 0° 13m 55.2s / day | |
| Inclination | 11.577° |
| 192.79° | |
| 268.97° | |
| Physical characteristics | |
| 12.244±0.003 h[10] | |
| 11.3[1][4] | |
920 Rogeria (prov. designation:A919 RCor1919 FT) is a darkbackground asteroid from the central region of theasteroid belt, discovered by German astronomerKarl Reinmuth at theHeidelberg-Königstuhl State Observatory on 1 September 1919.[1] TheD-type asteroid (DT) has arotation period of 12.2 hours and measures approximately 26 kilometers (16 miles) in diameter. It was named "Rogeria", a name unrelated to the discoverer's contemporaries, that was taken from the almanacLahrer Hinkender Bote.[2][3]
Rogeria, located in the orbital region of theEunomia family,[12] is a non-family asteroid of the main belt'sbackground population when applying thehierarchical clustering method to itsproper orbital elements.[5][6] It orbits the Sun in thecentral asteroid belt at a distance of 2.3–2.9 AU once every 4 years and 3 months (1,552 days;semi-major axis of 2.62 AU). Its orbit has aneccentricity of 0.11 and aninclination of 12° with respect to theecliptic.[4] The body'sobservation arc begins atHeidelberg Observatory with its official discovery observation.[1]
Thisminor planet was named after the feminine form of the name "Roger", picked from theLahrer Hinkender Bote, which was published inLahr, southern Germany.[2][3] AHinkender Bote (lit. "limping messenger") was a very popularalmanac, 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 5 January, the calendar gives "Roger" as the Germanname day analogue next toSimeon andTelesph., the protestant and catholic entries in thecalendar of saints, likely referring toSimeon Stylites andPope Telesphorus.[13]
As with 22 other asteroids – starting with913 Otila, and ending with1144 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 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 theTholen classification,Rogeria is closest to a darkD-type and somewhat similar to an uncommonT-type asteroid, though with an unusual spectrum (DTU).[4] D-type asteroids are more common further out the asteroid belt and among theJupiter trojan population. In theSDSS-based taxonomy,Rogeria is anX-type asteroid.[6][11]
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In October 2010, a rotationallightcurve ofRogeria was obtained fromphotometric observations byThomas A. Polakis at the Command Module Observatory (V02) in Arizona. Lightcurve analysis gave arotation period of12.244±0.003 hours with a brightness variation of0.31±0.03magnitude (U=3−).[10] A tentative period determination of9.05±0.05 hours with an amplitude of0.21±0.01 magnitude was made by French amateur French astronomerRené Roy in July 2012 (U=2−).[14] Another observation byPetr Pravec andPeter Kušnirák atOndřejov Observatory in June 2007 gave a period of 8.09 hours (U=2−).[a]
In 2016, a modeled lightcurve gave a concurring sidereal period of12.5749±0.0002 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 of (238.0°, −15.0°) and (47.0°, −35.0°) inecliptic coordinates (λ, β).[15]
According to the survey carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite, and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE),Rogeria measures (23.89±0.9), (25.80±0.36) and (26.656±0.168) kilometers in diameter and its surface has a lowalbedo of (0.1035±0.008), (0.090±0.003) and (0.076±0.012), respectively.[7][8][9]
TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.0613 and a diameter of 29.71 km based on anabsolute magnitude of 11.285.[12] Further published mean-diameters and albedos by the WISE team include (22.03±4.45 km), (23.69±7.40 km) and (29.683±0.260 km) with corresponding albedos of (0.09±0.06), (0.09±0.05) and (0.0670±0.0030).[6][12]
