_Deira.png) Modelled shape ofDeira from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | C. Jackson |
| Discovery site | Johannesburg Obs. |
| Discovery date | 25 May 1932 |
| Designations | |
| (1244) Deira | |
| Pronunciation | /ˈdaɪrə/DY-rə or/ˈdɛərə/DAIR-ə[2] |
Named after | Deira, near the town ofOssett, England[3] (alt. CelticKingdom of Deira) |
| 1932 KE · 1930 YR 1984 YQ6 · A908 TD A921 GC · A924 BH | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 109.13 yr (39,861 days) |
| Aphelion | 2.5731AU |
| Perihelion | 2.1129 AU |
| 2.3430 AU | |
| Eccentricity | 0.0982 |
| 3.59yr (1,310 days) | |
| 335.23° | |
| 0° 16m 29.28s / day | |
| Inclination | 8.6950° |
| 277.12° | |
| 261.45° | |
| Physical characteristics | |
| 28.816±0.546 km[7] 30.432±9.136 km[8] 30.95±1.9 km[9] 31.799±0.487 km[10] 32.28±0.35 km[11] 33.15±7.01 km[12] 35.19±0.19 km[13] | |
| 5(poor)h[14] 210.6±0.1 h[a] 216.98±0.05 h[15] 217.1±0.1 h[b] | |
| 0.03±0.00[13] 0.0357±0.0051[10] 0.037±0.011[12] 0.0416±0.0312[8] 0.052±0.001[11] 0.0557±0.007[9] | |
| 11.30[9][10][11] 11.50[1][17][8] | |
1244 Deira (prov. designation:1932 KE) is a darkbackground asteroid andslow rotator from the inner region of theasteroid belt. TheX-type asteroid has an exceptionally longrotation period of 210.6 hours and measures approximately 31 kilometers (19 miles) in diameter. It was discovered on 25 May 1932, by English-born South African astronomerCyril Jackson at theUnion Observatory in Johannesburg,[4] who named it afterDeira, an old kingdom near his birthplace, the market town ofOssett, located in West Yorkshire, England.[3]
Deira 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 theinner asteroid belt at a distance of 2.1–2.6 AU once every 3 years and 7 months (1,310 days;semi-major axis 2.34 AU). Its orbit has aneccentricity of 0.10 and aninclination of 9° with respect to theecliptic.[1] The body'sobservation arc begins with its first observations asA908 TD atHeidelberg Observatory in October 1908, or more than 23 years prior to its official discovery observation at Johannesburg.[4]
Thisminor planet was named by the discovererCyril Jackson after his birthplace, the market town ofOssett, located in West Yorkshire, England(also see2193 Jackson).[3] The official naming citation was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 115).[3] While the naming citation reads thatDeira is the ancient name for his birthplace, the CelticKingdom of Deira was actually much larger, encompassing at its height most ofYorkshire in Northern England.
Deira has been characterized as a primitiveP-type asteroid by the space-basedWide-field Infrared Survey Explorer (WISE).[10] While P-type bodies are common in the outermost asteroid belt and among theJupiter trojans, they are rarely found in the inner main belt. In both the Tholen- and SMASS-like taxonomy of theSmall Solar System Objects Spectroscopic Survey (S3OS2),Deira is anX-type asteroid.[6][16]
In March 2011, a rotationallightcurve ofDeira was obtained from photometric observations byJulian Oey at his Leura Observatory (E17) in Australia. Lightcurve analysis gave arotation period of 210.6 hours with a brightness variation of 0.5magnitude (U=2),[a] while Oey previously published a slightly longer period of 217.1 hours and an amplitude of 0.6 magnitude (U=n.a.).[b] This makesDeira one of theTop 300 slow rotators known to exist.
In 2016, an international study modeled a lightcurve with a concurring period of 216.98 hours and found twospin axis of (314.0°, −46.0°) and (107.0°, −56.0°) inecliptic coordinates (λ, β).[15]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite and theNEOWISE mission of NASA's WISE telescope,Deira measures between 28.816 and 35.19 kilometers in diameter and its surface has analbedo between 0.03 and 0.0557.[7][8][9][10][11][12][13]
TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.0465 and a diameter of 30.89 kilometers based on anabsolute magnitude of 11.5.[17]
