| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 22 November 1929 |
| Designations | |
| (1138) Attica | |
| Pronunciation | /ˈætɪkə/[2] |
Named after | Attica Province (province of Greece)[3] |
| 1929 WF · 1954 GK | |
| main-belt · (outer) | |
| Orbital characteristics[1] | |
| Epoch 16 February 2017 (JD 2457800.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 86.52 yr (31,600 days) |
| Aphelion | 3.3801AU |
| Perihelion | 2.9104 AU |
| 3.1453 AU | |
| Eccentricity | 0.0747 |
| 5.58yr (2,037 days) | |
| 249.74° | |
| 0° 10m 36.12s / day | |
| Inclination | 13.971° |
| 283.50° | |
| 107.03° | |
| Physical characteristics | |
| Dimensions | 23.681±0.113 km[4] 30±2 km(generic)[5] |
| unknown[6] | |
| 0.105±0.018[4] | |
| 11.4[1] | |
1138 Attica, provisional designation1929 WF, is anasteroid from the outer region of theasteroid belt, approximately 24 kilometers in diameter. It was discovered on 22 November 1929, by German astronomerKarl Reinmuth atHeidelberg Observatory in southwest Germany.[7] It was named after theAttica Province in Greece.[3]
Attica orbits the Sun in theouter main-belt at a distance of 2.9–3.4 AU once every 5 years and 7 months (2,037 days). Its orbit has aneccentricity of 0.07 and aninclination of 14° with respect to theecliptic.[1] The body'sobservation arc begins at Heidelberg with its official discovery observation. Noprecoveries were taken, and no prior identifications were made.[7]
According to the survey carried out by NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Attica measures 23.681 kilometers in diameter and its surface has analbedo of 0.105.[4] Based on a genericmagnitude-to-diameter conversion, its diameter is between 13 and 32 kilometer for anabsolute magnitude of 11.4 and an assumed albedo in the range of 0.05 to 0.25.[5] Since asteroids in the outer main-belt are typically ofcarbonaceous rather thanstony composition, with averaged standard albedos of 0.057,Attica's diameter can be estimated to measure close to 30 kilometers, as the lower a body's albedo (reflectivity), the larger its diameter at a fixedabsolute magnitude (brightness).[5]
As of 2017,Attica'sspectral type, as well as itsrotation period and shape remain unknown.[1][6] This is rather unusual, as both spectral type and rotation period have been determined for most larger and low-numbered asteroids(also see minor-planet lists from1 up to2000).
Thisminor planet is named after theprovince of Attica in eastern Greece with the capitalAthens.[3] Naming citation was first mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 102).[3]
