779 Nina (prov. designation: A914 BHor1914 UB) is a large background asteroid, approximately 80 kilometers (50 miles) in diameter, located in the central region of the asteroid belt. It was discovered on 25 January 1914, by Russian astronomer Grigory Neujmin(1886-1946) at the Simeiz Observatory on the Crimean peninsula.[1] The metallic X-type asteroid with an intermediate albedo has a rotation period of 11.2 hours. It was named after the discoverer's sister, Nina Neujmina (Tsentilovich) (1889–1971).[2]
This minor planet was named after Nina Nikolaevna Neujmina (Tsentilovich) (1889–1971), mathematician and sister of Russian discoverer Grigory Neujmin(1886-1946).[2]
In June 1981, a rotational lightcurve of Nina was obtained from photometric observations by Alan Harris at the Table Mountain and Lowell observatories. Lightcurve analysis gave a rotation period of 11.186 hours with a brightness variation of 0.25magnitude (U=3).[10] It was confirmed by Brian Warner at his Palmer Divide Observatory (716) in Colorado in January 2009, who determined a period of 11.17±0.01 hours with an amplitude of 0.32±0.02 magnitude (U=3).[15][a] In September 2012, French amateur astronomer Gérald Rousseau obtained a period of 11.556±0.002 hours with an amplitude of 0.06 magnitude (U=2+).[16]
Diameter and albedo
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), and the Japanese Akari satellite, Nina measures (76.62±4.0), (80.572±2.220) and (81.27±1.00) kilometers in diameter and its surface has an albedo of (0.1440±0.016), (0.157±0.022) and (0.132±0.004), respectively.[7][8][9] The Collaborative Asteroid Lightcurve Link adopts Petr Pravec's revised WISE-albedo of 0.1694 and takes a diameter of 77.46 kilometers based on an absolute magnitude of 8.1.[13][14] The WISE team also published an alternative mean-diameter of (77.000±6.578 km) with an albedo of (0.1740±0.0559).[13] On 10 November 2005, an asteroid occultation of Nina gave a best-fit ellipse dimension of (79.9 km × 79.9 km), with a quality rating of 2. These timed observations are taken when the asteroid passes in front of a distant star.[5]
Notes
^Lightcurve plot of (779) Nina, Palmer Divide Observatory, Brian Warner (2009). Rotation period 11.17±0.01 hours with a brightness amplitude of 0.32±0.02 mag. Quality code is 3. Summary figures at the LCDB.
^ 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)
^ abPravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus. 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026.