.png) Lightcurve-based 3D-model ofDysona | |
| Discovery[1] | |
|---|---|
| Discovered by | H. E. Wood |
| Discovery site | Johannesburg Obs. |
| Discovery date | 4 March 1932 |
| Designations | |
| (1241) Dysona | |
Named after | Frank Watson Dyson[2] (English astronomer) |
| 1932 EB1 · 1931 AA1 1945 RA · 1948 CE 1956 PB · A908 DC A920 EB | |
| main-belt · (outer)[3] background[4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 97.31 yr (35,542 days) |
| Aphelion | 3.5165AU |
| Perihelion | 2.8633 AU |
| 3.1899 AU | |
| Eccentricity | 0.1024 |
| 5.70yr (2,081 days) | |
| 290.13° | |
| 0° 10m 22.8s / day | |
| Inclination | 23.518° |
| 322.27° | |
| 320.07° | |
| Physical characteristics | |
| Dimensions | 70.757±0.287 km[5] 74.83±28.44 km[6] 75.62±0.82 km[7] 77.14±0.86 km[8] 77.47±26.72 km[9] 79.190±0.694 km[10] 83.05±4.4 km[11] |
| 8.355±0.001h[12] 8.60738 h[13] 8.6080±0.0005 h[14] | |
| 0.04±0.05[9] 0.0425±0.005[11] 0.047±0.003[10] 0.05±0.05[6] 0.051±0.001[8] 0.051±0.005[7] 0.0585±0.0120[5] | |
| Tholen = PDC[1][3] B–V = 0.750[1] U–B = 0.290[1] | |
| 9.45[1][3][5][6][7][8][11] · 9.74[9] | |
1241 Dysona, provisional designation1932 EB1, is a dark backgroundasteroid from the outer regions of theasteroid belt, approximately 77 kilometers in diameter. It was discovered on 4 March 1932, by English astronomerHarry Edwin Wood at theUnion Observatory in Johannesburg, South Africa.[15] The asteroid was named after English astronomerFrank Watson Dyson.[2]
Dysona is a non-family asteroid from the main belt'sbackground population.[4] It orbits the Sun in theouter main-belt at a distance of 2.9–3.5 AU once every 5 years and 8 months (2,081 days;semi-major axis of 3.19 AU). Its orbit has aneccentricity of 0.10 and aninclination of 24° with respect to theecliptic.[1]
The asteroid was first observed asA908 DC at Taunton Observatory (803) in February 1908. The body'sobservation arc begins with its observations asA920 EB atHeidelberg Observatory in March 1920, or 12 years prior to its official discovery observation at Johannesburg.[15]
In theTholen classification,Dysona'sspectral type is ambiguous, closest to a primitiveP-type and somewhat similar to aD- andC-type asteroid (PDC).[1][3]
In April 2006, a rotationallightcurve ofDysona was obtained byJulian Oey at Leura Observatory (E17) in Australia. Lightcurve analysis gave arotation period of 8.6080 hours with a brightness variation of 0.24magnitude (U=3-),[14] superseding photometric observations by Jean-Gabriel Bosch and Laurent Brunetto in October 2010, who measured a period of 8.355 hours and an amplitude of 0.25 magnitude (U=2).[12]
In 2016, a modeled lightcurve using data from UAPC, thePalomar Transient Factory survey, and individual observers, gave a concurring period of 8.60738 hours as well anastronomical pole of (125.0°, −68.0°) inecliptic coordinates (λ, β).[13]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Dysona measures between 70.757 and 83.05 kilometers in diameter and its surface has analbedo between 0.04 and 0.0585.[5][6][7][8][9][10][11]
TheCollaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0425 and a diameter of 83.05 kilometers based on anabsolute magnitude of 9.45.[3]
Thisminor planet was named after English astronomerFrank Watson Dyson (1868–1939),Astronomer Royal of England, director of theRoyal Observatory, Greenwich, awarded theBruce Medal in 1922, and president of theInternational Astronomical Union from 1928 to 1932. The official naming citation was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 114). The lunar craterDyson was also named in his honor.[2]
