| Discovery[1] | |
|---|---|
| Discovered by | Y. Väisälä |
| Discovery site | Turku Obs. |
| Discovery date | 18 March 1939 |
| Designations | |
| (1696) Nurmela | |
Named after | Tauno Nurmela (University of Turku)[2] |
| 1939 FF · 1939 GL 1949 DK · 1951 YK | |
| main-belt[1][3] · inner Baptistina[4][5] · Flora[6] | |
| Orbital characteristics[3] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 78.30yr (28,598 d) |
| Aphelion | 2.4842AU |
| Perihelion | 2.0391 AU |
| 2.2616 AU | |
| Eccentricity | 0.0984 |
| 3.40 yr (1,242 d) | |
| 76.752° | |
| 0° 17m 23.28s / day | |
| Inclination | 6.0374° |
| 21.035° | |
| 164.84° | |
| Physical characteristics | |
| 6.06±1.18 km[7] 7.69±2.07 km[8] 9.232±0.181 km[9] 9.911±0.056 km[10] 10.31±0.44 km[11] 14.64 km(calculated)[4] | |
| 3.1587±0.0001 h[12] 3.1587±0.0001 h[13] 3.159±0.001 h[14][a] | |
| 0.057(assumed)[4] 0.116±0.011[11] 0.1246±0.0166[10] 0.155±0.021[9] 0.18±0.13[8] 0.28±0.20[7] | |
| C(assumed)[4] | |
| 12.90[3][4][7][10][11] 13.19[8] | |
1696 Nurmela, provisional designation1939 FF, is a Baptistinaasteroid from the inner regions of theasteroid belt, approximately 10 kilometers (6 miles) in diameter. It was discovered on 18 March 1939, by Finnish astronomerYrjö Väisälä atTurku Observatory in Southwest Finland, and named after Finnish academicianTauno Nurmela.[2][1] The possibly elongated asteroid has arotation period of 3.15 hours.[4]
Nurmela is the second-largest member of the smallBaptistina family (403), a large inner-belt family, named after298 Baptistina, its largest member and namesake.[4][5] When applying thehierarchical clustering method to itsproper orbital elements, it is also a member of theFlora family (402),[6] a giantasteroid family and the largest family of stony asteroids in the main-belt.[15]: 23
It orbits the Sun in theinner main-belt at a distance of 2.0–2.5 AU once every 3 years and 5 months (1,242 days;semi-major axis of 2.26 AU). Its orbit has aneccentricity of 0.10 and aninclination of 6° with respect to theecliptic.[3] The body'sobservation arc begins with its official discovery observation at Turku.[1]
Nurmela is an assumed carbonaceousC-type asteroid,[4] while its albedo and membership to the Baptistina family is indicative for anX-type.[15]: 23
In March and April 2007, two rotationallightcurves ofNurmela was obtained from photometric observations byAdrián Galád andRobert Stephens. They gave an identicalrotation period of 3.1587 hours with a brightness variation of 0.33 and 0.42magnitude, respectively (U=3/3).[13][12] In April 2017, another observation by Stephens gave a concurring period of 3.159 hours (U=3) with an amplitude of 0.58 magnitude, indicative for an elongated shape.[14][a]
According to the surveys carried out by the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Nurmela measures between 6.06 and 10.31 kilometers in diameter and its surface has analbedo between 0.116 and 0.28.[7][8][9][10][11]
TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 14.64 kilometers based on anabsolute magnitude of 12.9.[4]
Thisminor planet was named in honor of Finnish academician Tauno Kalervo Nurmela (1907–1985), some time professor of Romanic philology and later chancellor ofUniversity of Turku.[2] The official naming citation was published by theMinor Planet Center on 1 April 1980 (M.P.C. 5281).[16]
