_Sekiguchi.png) Shape model ofSekiguchi from itslightcurve | |
| Discovery [1] | |
|---|---|
| Discovered by | T. Fujii K. Watanabe |
| Discovery site | Kitami Obs. |
| Discovery date | 2 March 1992 |
| Designations | |
| (5357) Sekiguchi | |
Named after | Tomohiko Sekiguch (Japanese astronomer)[2] |
| 1992 EL · 1969 TB4 1971 BE3 · 1981 BH 1990 VJ4 · 1990 WU13 | |
| main-belt · (outer)[3] Eos [4] | |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 67.13 yr (24,518 days) |
| Aphelion | 3.2966AU |
| Perihelion | 2.6794 AU |
| 2.9880 AU | |
| Eccentricity | 0.1033 |
| 5.17yr (1,887 days) | |
| 75.618° | |
| 0° 11m 26.88s / day | |
| Inclination | 9.0838° |
| 301.97° | |
| 116.81° | |
| Physical characteristics | |
| 13.948±0.118 km[5] 14.281±0.193 km[6] 14.52±0.65 km[7] 15.19±1.13 km[8] | |
| 5.4048±0.0011 h[9] 5.4100±0.0011 h[9] 5.41±0.01 h[10] | |
| 0.192±0.032[5][7] 0.334±0.052[8] 0.3829±0.0259[6] | |
| C [3] | |
| 10.9[6][8] · 11.60[7] · 11.624±0.002(R)[9] · 11.7[1][3] · 11.719±0.003(R)[9] | |
5357 Sekiguchi (prov. designation:1992 EL) is anEos asteroid from the outer region of theasteroid belt, approximately 15 kilometers (9 miles) in diameter. It was discovered on 2 March 1992, by Japanese amateur astronomersTetsuya Fujii andKazuro Watanabe at theKitami Observatory in eastern Hokkaidō, Japan. The asteroid was later named after Japanese astronomerTomohiko Sekiguch.[2]
Sekiguchi is a member theEos family (606),[4] the largestasteroid family of theouter main belt consisting of nearly 10,000 asteroids.[11]: 23 It orbits the Sun at a distance of 2.7–3.3 AU once every 5 years and 2 months (1,887 days). Its orbit has aneccentricity of 0.10 and aninclination of 9° with respect to theecliptic.[1] The firstprecovery was obtained atGoethe Link Observatory in 1950, extending the asteroid'sobservation arc by 42 years prior to its discovery.[2]
Thisminor planet was named in honor of Japanese astronomer Tomohiko Sekiguch (born 1970), associate professor atHokkaido University. From 1998 to 2001, he had been observing minor planets at theEuropean Southern Observatory.[2] The official naming citation was published by theMinor Planet Center on 6 April 2012 (M.P.C. 79102).[12]
In October 2005, a rotationallightcurve ofSekiguchi was obtained from photometric observations by French amateur astronomersRené Roy andLaurent Bernasconi. Lightcurve analysis gave a well-definedrotation period of5.41 hours with a brightness variation of 0.72magnitude (U=3).[10]
In October 2010 and November 2011, two more lightcurves were obtained at thePalomar Transient Factory, rendering a period of 5.4048 and 5.4100 hours with an amplitude of 0.58 and 0.27 magnitude, respectively (U=2/2).[9]
According to the surveys carried out by the JapaneseAkari satellite and NASA'sWide-field Infrared Survey Explorer with itsNEOWISE mission,Sekiguchi measures between 13.9 and 15.2 kilometers in diameter and its surface has analbedo between 0.192 and 0.3829.[6][7][8] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo forcarbonaceous asteroids of 0.057 and consequently calculates a larger diameter of 25.4 kilometers with anabsolute magnitude of 11.7.[3]
