1696 Nurmela, provisional designation 1939 FF, is a Baptistina asteroid from the inner regions of the asteroid belt, approximately 10 kilometers (6 miles) in diameter. It was discovered on 18 March 1939, by Finnish astronomer Yrjö VäisäläatTurku Observatory in Southwest Finland, and named after Finnish academician Tauno Nurmela.[2][1] The possibly elongated asteroid has a rotation period of 3.15 hours.[4]
It orbits the Sun in the inner 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 an eccentricity of 0.10 and an inclination of 6° with respect to the ecliptic.[3] The body's observation arc begins with its official discovery observation at Turku.[1]
In March and April 2007, two rotational lightcurvesofNurmela was obtained from photometric observations by Adrián Galád and Robert Stephens. They gave an identical rotation period of 3.1587 hours with a brightness variation of 0.33 and 0.42 magnitude, 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]
The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 14.64 kilometers based on an absolute magnitude of 12.9.[4]
This minor planet was named in honor of Finnish academician Tauno Kalervo Nurmela (1907–1985), some time professor of Romanic philology and later chancellor of University of Turku.[2] The official naming citation was published by the Minor Planet Center on 1 April 1980 (M.P.C. 5281).[16]
^ abLightcurve plot of (1696) Nurmela, by Stephens at the CS3 (U81) in April 2017, with rotation period 3.159±0.001 hours and a brightness amplitude of 0.58±0.02 mag. Quality code of 3. Summary figures at the LCDB
^ abcdNugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117.
^ abcMasiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121.
^ abcdUsui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)