| Discovery[1] | |
|---|---|
| Discovered by | J. A. Bruwer |
| Discovery site | Johannesburg Obs. |
| Discovery date | 13 July 1953 |
| Designations | |
| (1658) Innes | |
Named after | Robert T. A. Innes (astronomer)[2] |
| 1953 NA · 1940 GB 1948 EM · 1949 QA 1953 OF · 1953 PN 1957 OE | |
| main-belt · (middle) | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 77.08 yr (28,155 days) |
| Aphelion | 3.0302AU |
| Perihelion | 2.0866 AU |
| 2.5584 AU | |
| Eccentricity | 0.1844 |
| 4.09yr (1,495 days) | |
| 247.27° | |
| 0° 14m 27.24s / day | |
| Inclination | 9.0941° |
| 95.441° | |
| 188.76° | |
| Physical characteristics | |
| Dimensions | 13.352±0.140 km[3] 13.54±1.17 km[4] 14.082±0.042 km[5] 14.76 km(calculated)[6] |
| 3.191±0.001h[7][8] | |
| 0.20(assumed)[6] 0.2241±0.0369[5] 0.248±0.019[3] 0.626±0.318[4] | |
| B–V = 0.960[1] U–B = 0.610[1] Tholen = AS[1] · AS[6] | |
| 11.27±0.41[9] · 10.47[4] · 11.52[1][6][5] | |
1658 Innes, provisional designation1953 NA, is a rare-typeasteroid from the middle region of theasteroid belt, approximately 15 kilometers in diameter. It was named afterRobert T. A. Innes.
Innes was discovered on 13 July 1953, by South African astronomerJacobus Bruwer atJohannesburg Observatory in South Africa.[10]
It was the first numbered discovery of astronomer Jacobus Bruwer. In addition, he also discovered the minor planets1660 Wood,1794 Finsen, and3284 Niebuhr. The asteroid1811 Bruwer was named in his honour by the Dutch, Dutch-American astronomer trio of thePalomar–Leiden survey.[11]
It orbits the Sun in thecentral main-belt at a distance of 2.1–3.0 AU once every 4 years and 1 month (1,495 days). Its orbit has aneccentricity of 0.18 and aninclination of 9° with respect to theecliptic.[1]Innes was first identified as1940 GB atTurku Observatory in 1940, extending the body'sobservation arc by 13 years prior to its official discovery observation.[10]
In theTholen taxonomy,Innes has an AS-spectral type, an intermediate form of the rareA-types to the commonstony asteroids(also seecategory listing).[12]
In May 2005, astronomersRobert Stephens at the Center for Solar System Studies, California, and Lorenzo Franco at Balzaretto Observatory, near Rome, each obtained a rotationallightcurve ofInnes. The photometric observations gave an identicalrotation period of3.191±0.001 hours with a brightness variation of 0.22 and 0.25magnitude, respectively (U=3/3).[7][8]
According to the 2014-revised survey result of NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Innes measures 13.35 kilometers in diameter and its surface has analbedo of 0.248,[3] while theCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 14.76 kilometers with anabsolute magnitude of 11.52.[6]
Thisminor planet was named for Scottish–South African astronomerRobert T. A. Innes (1861–1933), first director of the discovering Union Observatory from 1903 to 1927 (originally named Transvaal Observatory). He was a skilledobservational astronomer, famous for his deliberate search for and discovery of the nearest star,Proxima Centauri, in 1915. He also made important theoretical and computational contributions tocelestial mechanics and to the irregularrotation of the Earth. The astronomer is also honored by the lunar craterInnes.[2] The officialnaming citation was published by theMinor Planet Center on 1 July 1972 (M.P.C. 3297).[13]
