.png) Lightcurve-based 3D-model ofOtthild | |
| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 18 March 1923 |
| Designations | |
| (994) Otthild | |
Named after | Name picked from the almanac Lahrer Hinkender Bote[2][3] |
| A923 FB · 1923 NL 1960 KC · 1967 CM 1967 EK1 · 1923 NL | |
| main-belt[1][4] · (middle) background[5] | |
| Orbital characteristics[4] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 96.15yr (35,119 d) |
| Aphelion | 2.8235AU |
| Perihelion | 2.2349 AU |
| 2.5292 AU | |
| Eccentricity | 0.1164 |
| 4.02 yr (1,469 d) | |
| 156.20° | |
| 0° 14m 42s / day | |
| Inclination | 15.411° |
| 2.3500° | |
| 342.50° | |
| Physical characteristics | |
| 5.9473±0.0001 h[9][a] | |
| 10.2[1][4] | |
994 Otthild (prov. designation:A923 FBor 1923 NL) is a stonybackground asteroid from the central regions of theasteroid belt, approximately 24 kilometers (15 miles) in diameter. It was discovered on 18 March 1923, by astronomerKarl Reinmuth at theHeidelberg-Königstuhl State Observatory.[1] TheS-type asteroid has arotation period of 5.95 hours and is rather regular in shape. It was named after a common German female name, unrelated to the discoverer's contemporaries, and taken from the almanacLahrer Hinkender Bote.[2][3]
Otthild is a non-family asteroid of the main belt'sbackground population when applying thehierarchical clustering method to itsproper orbital elements.[5] It orbits the Sun in thecentral asteroid belt at a distance of 2.2–2.8 AU once every 4 years (1,469 days;semi-major axis of 2.53 AU). Its orbit has aneccentricity of 0.12 and aninclination of 15° with respect to theecliptic.[4] The body'sobservation arc begins on 20 March 1931 at Heidelberg just two days after its official discovery observation.[1]
Thisminor planet was named Otthild, after a female name picked from theLahrer Hinkender Bote, 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 the second of July, the calendar gives "Otto" and "Otthild" as the German analogue for the catholic and protestant feast-days (Mary's Visitation and Otto).[11]
As with913 Otila,997 Priska and1144 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. 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,Otthild is a common, stonyS-type asteroid.[4][10]
In October 2005, a rotationallightcurve ofOtthild was obtained fromphotometric observations by European observersReiner Stoss,Jaume Nomen,Salvador Sanchez,Raoul Behrend andLaurent Bernasconi. Lightcurve analysis gave arotation period of5.9473±0.0001 hours with a relatively low brightness amplitude of0.15±0.01magnitude (U=2+), which is indicative of a regular shape.[9][12][a]
A modeled lightcurve gave a concurring sidereal period of 5.94819 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 (183.0°, −50.0°) and (41.0°, −39.0°) inecliptic coordinates (λ, β).[13]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Otthild measures (20.786±1.371) kilometers in diameter and its surface has analbedo of (0.310±0.036).[6] The JapaneseAkari satellite and the Infrared Astronomical SatelliteIRAS determined a somewhat larger diameter of (24.34±0.61) and (24.42±1.6) kilometers with an albedo of (0.227±0.013) and (0.2247±0.032), respectively.[7][8] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.2136 and a diameter of 24.36 kilometers based on anabsolute magnitude of 10.36.[12]
