1689 Floris-Jan
Main-belt asteroid
From Wikipedia, the free encyclopedia
1689 Floris-Jan, provisional designation 1930 SO, is a stony asteroid and a slow rotator from the inner regions of the asteroid belt, approximately 16 kilometers in diameter. Discovered by Hendrik van Gent in 1930, it was named after a contest winner of an exhibition at Leiden Observatory.
(Leiden Southern Station)
| Discovery[1] | |
|---|---|
| Discovered by | H. van Gent |
| Discovery site | Johannesburg Obs. (Leiden Southern Station) |
| Discovery date | 16 September 1930 |
| Designations | |
| (1689) Floris-Jan | |
Named after | Floris-Jan van der Meulen (Contest Winner)[2] |
| 1930 SO · 1926 PG 1928 DN · 1934 VV 1943 AC · 1949 OF 1949 ON1 · 1949 OY 1951 CW · 1966 BP | |
| main-belt · (inner)[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 89.19 yr (32,577 days) |
| Aphelion | 2.9545 AU |
| Perihelion | 1.9461 AU |
| 2.4503 AU | |
| Eccentricity | 0.2058 |
| 3.84 yr (1,401 days) | |
| 218.98° | |
| 0° 15m 25.2s / day | |
| Inclination | 6.3757° |
| 123.19° | |
| 265.10° | |
| Physical characteristics | |
| Dimensions | 13.743±1.905 km[4] 13.99±0.23 km[5] 16.122±4.950 km[6] 16.21 km (taken)[3] 16.213 km[7] |
| 0.083 h (fragm.)[8] 144.85±0.20 h[9] 145 h[10] | |
| 0.1271±0.0508[6] 0.1353[7] 0.175±0.050[4] 0.184±0.007[5] | |
| S[3] B–V = 0.685[1] U–B = 0.265[1] | |
| 11.74±0.05[3][7][9] · 11.79±0.19[11] · 11.82[1][4][5][6] | |
Discovery
The asteroid was discovered on 16 September 1930, by Dutch astronomer Hendrik van Gent at the Leiden Southern Station, annex to the Johannesburg Observatory in South Africa.[12] It was independently discovered by Soviet astronomer Evgenii Skvortsov at the Crimean Simeiz Observatory five days later.[2]
Orbit and classification
Floris-Jan orbits the Sun in the inner main-belt at a distance of 1.9–3.0 AU once every 3 years and 10 months (1,401 days). Its orbit has an eccentricity of 0.21 and an inclination of 6° with respect to the ecliptic.[1] First identified as 1926 PG at Simeiz Observatory in 1926, the body's observation arc begins 3 days after its official discovery observation at Johannesburg in 1930.[12]
Physical characteristics
Slow rotator
In the 1980s, photometric lightcurve observations already revealed that Floris-Jan is a very slow rotator with a rotation period of 145 hours and a brightness variation of 0.4 magnitude (U=3).[10] At the time, this six-day period was a new record among all minor planets with a known rotation period, and it was assumed, that Floris-Jan might also be a tumbling asteroid with a non-principal axis rotation.[3][9]
Diameter and albedo
According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Floris-Jan measures between 13.74 and 16.12 kilometers in diameter, and its surface has an albedo between 0.127 and 0.184.[4][5][6] The Collaborative Asteroid Lightcurve Link agrees with Petr Pravec's revised WISE-data, that is an albedo of 0.135 and a diameter of 16.21 kilometers based on an absolute magnitude of 11.74.[3]
Naming
This minor planet was named for Floris-Jan van der Meulen, the 5,000th visitor to a 14-day astronomical exhibition at the Leiden Observatory.[2] The official naming citation was published by the Minor Planet Center on 1 March 1973 (M.P.C. 3470).[13]
