Astronomy:3430 Bradfield
_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 | |
| Minor planet category | 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) |
| |{{{apsis}}}|helion}} | 3.0293 AU |
| |{{{apsis}}}|helion}} | 2.4890 AU |
| 2.7592 AU | |
| Eccentricity | 0.0979 |
| Orbital period | 4.58 yr (1,674 d) |
| Mean anomaly | 102.11° |
| Mean motion | 0° 12m 54s / day |
| Inclination | 4.4281° |
| Longitude of ascending node | 43.225° |
| 278.60° | |
| Physical characteristics | |
| Mean diameter | 8.492±0.263 km[4] |
| Geometric albedo | 0.269±0.035[4] |
| SMASS = Sq [2] | |
| Absolute magnitude (H) | 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]
Orbit and classification
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]
Physical characteristics
In the SMASS classification, Bradfield is an Sq-subtype, that transitions between the common, stony S-type and Q-type asteroids.[2]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Bradfield measures 8.492 kilometers in diameter and its surface has an albedo of 0.269.[4]
Rotation period
As of 2018, no rotational lightcurve of Bradfield has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.[2]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 "3430 Bradfield (1980 TF4)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=3430.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 "JPL Small-Body Database Browser: 3430 Bradfield (1980 TF4)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2003430.
- ↑ 3.0 3.1 3.2 "Asteroid 3430 Bradfield – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=3430+Bradfield#Asteroid%203430%20BradfieldEAR-A-VARGBDET-5-NESVORNYFAM-V3.0.
- ↑ 4.0 4.1 4.2 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J. et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal 741 (2): 20. doi:10.1088/0004-637X/741/2/68. Bibcode: 2011ApJ...741...68M.
- ↑ 5.0 5.1 Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families". Asteroids IV. pp. 297–321. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131. Bibcode: 2015aste.book..297N.
- ↑ Sunshine, Jessica M.; Bus, Schelte J.; McCoy, Timothy J.; Burbine, Thomas H.; Corrigan, Catherine M.; Binzel, Richard P. (August 2004). "High-calcium pyroxene as an indicator of igneous differentiation in asteroids and meteorites". Meteoritics and Planetary Science 39 (8): 1343–1357. doi:10.1111/j.1945-5100.2004.tb00950.x. Bibcode: 2004M&PS...39.1343S. https://www.researchgate.net/publication/228936637. Retrieved 12 April 2018.
- ↑ Zappalà, V.; Bendjoya, Ph.; Cellino, A.; Farinella, P.; Froeschle, C. (1997). "Asteroid Dynamical Families". NASA Planetary Data System: EAR-A-5-DDR-FAMILY-V4.1. https://sbnarchive.psi.edu/pds3/non_mission/EAR_A_5_DDR_FAMILY_V4_1/data/family.tab. Retrieved 19 March 2020.} (PDS main page)
- ↑ "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html.
External links
- Lightcurve Database Query (LCDB), at www.minorplanet.info
- Dictionary of Minor Planet Names, Google books
- Asteroids and comets rotation curves, CdR – Geneva Observatory, Raoul Behrend
- Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
- 3430 Bradfield at AstDyS-2, Asteroids—Dynamic Site
- 3430 Bradfield at the JPL Small-Body Database
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