| Discovery[1] | |
|---|---|
| Discovered by | R. H. McNaught |
| Discovery site | Siding Spring Obs. |
| Discovery date | 26 August 1989 |
| Designations | |
| (4713) Steel | |
Named after | Duncan Steel (New Zealand astronomer)[2] |
| 1989 QL | |
| main-belt · Hungaria[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 40.28 yr (14,713 days) |
| Aphelion | 2.0683AU |
| Perihelion | 1.7842 AU |
| 1.9263 AU | |
| Eccentricity | 0.0737 |
| 2.67yr (977 days) | |
| 236.36° | |
| 0° 22m 7.32s / day | |
| Inclination | 22.671° |
| 101.43° | |
| 152.56° | |
| Physical characteristics | |
| Dimensions | 5.62±0.53 km[4] 6.248±0.011 km[5] 6.286±0.055 km[6] 7.51 km(calculated)[3] |
| 5.186±0.004h[7] 5.193±0.002 h[8] 5.199±0.002 h[9] 5.203±0.002 h[10] | |
| 0.18(assumed)[3] 0.3468±0.0386[5] 0.381±0.036[6] 0.424±0.082[4] | |
| SMASS =A[1] · A[3] | |
| 12.8[4][5] · 13.1[1][3] · 13.18±0.25[11] | |
4713 Steel, provisional designation1989 QL, is a rare-type Hungariaasteroid from the inner regions of theasteroid belt, approximately 6 kilometers in diameter. It was discovered on 26 August 1989, by Scottish–Australian astronomerRobert McNaught at theSiding Spring Observatory in New South Wales, Australia.[12] It was named after astronomerDuncan Steel.[2]
The rare and reddishA-type asteroid is a member of theHungaria family, which form the innermost dense concentration of asteroids in the Solar System. It orbits the Sun in theinner main-belt at a distance of 1.8–2.1 AU once every 2 years and 8 months (977 days). Its orbit has aneccentricity of 0.07 and aninclination of 23° with respect to theecliptic.[1]
A firstprecovery was taken at the discovering observatory in 1976, extending the asteroid'sobservation arc by 13 years prior to its official discovery observation in 1989.[12]
In May 2005, the first rotationallightcurve was obtained for this asteroid from photometric observations made by French amateur astronomerLaurent Bernasconi. It gave arotation period of5.186±0.004 hours with a brightness variation of 0.44magnitude (U=3).[7]
Between May 2010 and December 2014, American astronomerBrian D. Warner obtained another 3 well-defined lightcurves at the U.S. Palmer Divide Station, Colorado. They gave a slightly longer period of 5.193–5.203 hours with an amplitude of 0.28 to 0.42 magnitude (U=3/3/3).[8][9][10]
According to the survey carried out by the JapaneseAkari satellite, the asteroid measures 5.6 kilometers in diameter and its surface has a highalbedo of 0.424,[4] while NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission determined a diameter of 6.2 and 6.3 kilometers with an albedo of 0.347 and 0.381, respectively.[5][6] TheCollaborative Asteroid Lightcurve Link assumes a much lower albedo of 0.18 and calculates a larger diameter of 7.5 kilometers with anabsolute magnitude of 13.1.[3]
Thisminor planet was named for English-born New ZealanderDuncan Steel (born 1955), astronomer anddiscoverer of minor planets, whose research focuses onsmall Solar System bodies, such as the dynamics of asteroids, comets andmeteoroids, and on meteoric impact rates. He has also demonstrated that various asteroids of theApollo group are the parents ofmeteor showers.[2] The approved naming citation was published by theMinor Planet Center on 30 March 1991 (M.P.C. 17982).[13]
