| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 30 September 1919 |
| Designations | |
| (923) Herluga | |
Named after | Name picked from the almanac Lahrer Hinkender Bote[2][3] |
| A919 SK · A915 VD 1919 GB · 1915 VD | |
| main-belt[1][4] · (middle) background[5][6] | |
| Orbital characteristics[4] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 99.61yr (36,382 d) |
| Aphelion | 3.1271AU |
| Perihelion | 2.1071 AU |
| 2.6171 AU | |
| Eccentricity | 0.1949 |
| 4.23 yr (1,546 d) | |
| 268.52° | |
| 0° 13m 58.08s / day | |
| Inclination | 14.458° |
| 197.52° | |
| 201.11° | |
| Physical characteristics | |
| 19.746±0.002 h[10] | |
| C(S3OS2)[11] | |
| 11.50[1][4] | |
923 Herluga (prov. designation:A919 SKor1919 GB) is a three-body resonantbackground asteroid, approximately 34 kilometers (21 miles) in diameter, located in the central region of theasteroid belt. It was discovered on 30 September 1919, by astronomerKarl Reinmuth at theHeidelberg Observatory in southwest Germany.[1] The carbonaceousC-type asteroid has arotation period of 19.7 hours. It was named "Herluga", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanacLahrer Hinkender Bote.[2][3]
Herluga is a non-family asteroid of the main belt'sbackground population when applying thehierarchical clustering method to itsproper orbital elements.[5][6] Located in the orbital region of theEunomia family,[12]Herluga orbits the Sun in thecentral asteroid belt at a distance of 2.1–3.1 AU once every 4 years and 3 months (1,546 days;semi-major axis of 2.62 AU). Its orbit has aneccentricity of 0.19 and aninclination of 14° with respect to theecliptic.[4] This brings the object into a pure three-bodyresonance (2/2/-1) with Jupiter and Saturn (ares 2.615 AU).[5][13]: 6 Other asteroids in this resonant group of 34 known objects include70 Panopaea,194 Prokne,258 Tyche,839 Valborg and995 Sternberga.[13]: 24 Herluga was first observed asA915 VD (1915 VD) atSimeiz Observatory on the Crimean peninsula on 9 November 1915. The body'sobservation arc begins atHeidelberg Observatory on 10 December 1919, more than two months after its official discovery observation.[1]
Thisminor planet was named "Herluga", 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. For 2 March, the calendar gives "Herluga" as the Germanname day analogue next toSimplizius andLuise, the protestant and catholic entries in thecalendar of saints.[14]
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 both the Tholen- and SMASS-like taxonomy of theSmall Solar System Objects Spectroscopic Survey (S3OS2),Herluga is a common, carbonaceousC-type asteroid.[6][11]
In November 2008, a rotationallightcurve ofHerluga was obtained fromphotometric observations by James W. Brinsfield at the Via Capote Observatory (G69) in California. Lightcurve analysis gave arotation period of19.746±0.002 hours with a brightness variation of0.16±0.02magnitude (U=2).[10] In August 2016, an alternative period determination of29.71±0.04 hours with an amplitude of0.28±0.02 mag was published (U=2).[15]
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,Herluga measures (32.47±0.8), (34.553±0.269) and (34.78±0.63) kilometers in diameter and its surface has a lowalbedo of (0.0421±0.002), (0.037±0.006) and (0.037±0.002), respectively.[7][8][9] TheCollaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0421 and a diameter of 32.47 km based on anabsolute magnitude of 11.5.[12] Further published mean-diameters by the WISE team in ascending order include (30.558±10.39 km), (31.89±10.59 km), (33.794±7.947 km), (34.142±10.733 km) and (37.638±0.190 km) with albedos between 0.03 and 0.06.[6][12]
