3430 Bradfield
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_Bradfield.png) Shape model of Bradfield from its lightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | C. Shoemaker |
| Discovery site | Palomar Obs. |
| Discovery date | 9 October 1980 |
| Designations | |
| (3430) Bradfield | |
Named after | William A. Bradfield (discoverer of comets) |
| 1980 TF4 · 1974 HY1 1976 YS7 | |
| main-belt[1][2] · (middle) Agnia[3] | |
| Orbital characteristics[2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 43.93 yr (16,044 d) |
| Aphelion | 3.0293 AU |
| Perihelion | 2.4890 AU |
| 2.7592 AU | |
| Eccentricity | 0.0979 |
| 4.58 yr (1,674 d) | |
| 102.11° | |
| 0° 12m 54s / day | |
| Inclination | 4.4281° |
| 43.225° | |
| 278.60° | |
| Physical characteristics | |
| 8.492±0.263 km[4] | |
| 0.269±0.035[4] | |
| SMASS = Sq[2] | |
| 12.5[1][2] | |
3430 Bradfield (prov. designation: 1980 TF4) is a stony Agnia asteroid from the central regions of the asteroid belt, approximately 8 kilometers (5 miles) in diameter. It was discovered on 9 October 1980, by American astronomer Carolyn Shoemaker at the Palomar Observatory in California. The Sq-type asteroid was named after comet hunter William A. Bradfield.[1]
When applying the hierarchical clustering method to its proper orbital elements according to Nesvorný, Bradfield is a member of the Agnia family (514),[3] a very large family of stony asteroids with more than 2000 known members.[5] They most likely formed from the breakup of a basalt object, which in turn was spawned from a larger parent body that underwent igneous differentiation.[6] The family's parent body and namesake is the asteroid 847 Agnia.[5] In the 1995-HCM analysis by Zappalà, however, it is a member of the Liberatrix family (also described as Nemesis family by Nesvorný).[3][7]
It orbits the Sun in the central main-belt at a distance of 2.5–3.0 AU once every 4 years and 7 months (1,674 days; semi-major axis of 2.76 AU). Its orbit has an eccentricity of 0.10 and an inclination of 4° with respect to the ecliptic.[2] The body's observation arc begins with its observations as 1974 HY1 at Cerro El Roble Observatory in April 1974, more than 6 years prior to its official discovery observation at Palomar.[1]
Naming
This minor planet was named after New Zealand-born Australian amateur astronomer and rocket engineer William A. Bradfield (1927–2014). A discoverer of several comets himself, he significantly increased the rate of discovery of bright comets from the southern hemisphere during the 1970s and 1980s.[1] The official naming citation was published by the Minor Planet Center on 14 April 1987 (M.P.C. 11750).[8]
