| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 20 October 1919 |
| Designations | |
| (924) Toni | |
Named after | Name picked from the almanac Lahrer Hinkender Bote[2][3] |
| A919 UF · 1919 GC A906 BA · 1906 BA A914 UD · 1914 UD | |
| main-belt[1][4] · (outer) background[5][6] | |
| Orbital characteristics[4] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 113.78yr (41,557 d) |
| Aphelion | 3.3879AU |
| Perihelion | 2.4888 AU |
| 2.9383 AU | |
| Eccentricity | 0.1530 |
| 5.04 yr (1,840 d) | |
| 355.92° | |
| 0° 11m 44.52s / day | |
| Inclination | 8.9872° |
| 150.19° | |
| 219.96° | |
| Physical characteristics | |
| 19.437±0.001 h[10][a] | |
| 9.4[1][4] | |
924 Toni (prov. designation:A919 UFor1919 GC) is a largebackground asteroid, approximately 80 kilometers (50 miles) in diameter, from the outer regions of theasteroid belt. It was discovered on 20 October 1919, by German astronomerKarl Reinmuth at theHeidelberg-Königstuhl State Observatory.[1] TheX-type asteroid has arotation period of 19.4 hours. It was named "Toni", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanacLahrer Hinkender Bote.[2][3]
Toni 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 theouter asteroid belt at a distance of 2.5–3.4 AU once every 5.04 years (1,840 days;semi-major axis of 2.94 AU). Its orbit has aneccentricity of 0.15 and aninclination of 9° with respect to theecliptic.[4] The asteroid was first observed asA906 BA (1906 BA) atHeidelberg Observatory on 20 January 1906, where the body'sobservation arc begins two days later on 20 January 1906, more than 13 years prior its official discovery observation.[1]
Thisminor planet was named "Toni", after a female name picked from theLahrer Hinkender Bote, published inLahr, southern Germany.[2] AHinkender Bote (lit. "limping messenger") was a very popularalmanac,[3] 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. The Germanname day analogue is given next to the protestant and catholic entries in thecalendar of saints(entry not found).
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 the Bus–BinzelSMASS classification,Toni is anX-type asteroid, while in theTholen classification, it is closest to a common, carbonaceousC-type asteroid and somewhat similar to an X-type (CX).[4][6]
In July 2014, a rotationallightcurve ofToni was obtained fromphotometric observations byFrederick Pilcher at the Organ Mesa Observatory (G50) in New Mexico.[a] Lightcurve analysis gave a well-definedrotation period of19.437±0.001 hours with a brightness amplitude of0.24±0.02magnitude (U=3).[10] This result supersedes previous observations with tentative period determinations by French amateur astronomersRené Roy andLaurent Bernasconi (U=1/1).[12]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE), the JapaneseAkari satellite, and the Infrared Astronomical SatelliteIRAS,Toni measures (71.983±25.283), (78.33±1.34) and (85.49±2.5) kilometers in diameter and its surface has a lowalbedo of (0.052±0.007), (0.054±0.002) and (0.0432±0.003), respectively.[6][7][8][9] TheCollaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0432 and a diameter of 85.49 km based on anabsolute magnitude of 9.37.[13] Further published mean-diameters and albedos by the WISE team include (84.874±26.15 km) and (94.58±0.38 km) and albedos of (0.0460±0.0477) and (0.04±0.01).[6][13]
