751 Faïna (prov. designation:A913 HEor1913 RK) is a very large background asteroid from the central regions of the asteroid belt, approximately 110 kilometers (68 miles) in diameter. It was discovered on 28 April 1913, by Russian astronomer Grigory Neujmin at the Simeiz Observatory on the Crimean peninsula.[1] The elongated C-type asteroid (Ch) has a rotation period of 23.7 hours. It was named after Faina Mikhajlovna Neujmina, colleague and first wife of the discoverer.[2]
In late 1988, a rotational lightcurve of Faïna was obtained from photometric observations by Richard Miles at the Manley Observatory near Chester in northwest England. Lightcurve analysis gave a well-defined rotation period of 23.678 hours with a brightness variation of 0.36magnitude (U=3).[12] Alternative observations by Roberto Crippa, Federico Manzini (2006) as well as by Bruno Christmann (2019) determined a period of 10+ and (11.846±0.007) hours (or half the period) with an amplitude of 0.02 and 0.18±0.01 magnitude (U=1/2).[13][15]
Diameter and albedo
According to the surveys carried out by the Japanese Akari satellite, the Infrared Astronomical Satellite IRAS, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), Faïna measures (106.81±1.28), (110.50±4.3) and (113.699±2.449) kilometers in diameter and its surface has a low albedo of (0.055±0.002), (0.0497±0.004) and (0.047±0.013), respectively.[7][8][9][10]
The Collaborative Asteroid Lightcurve Link adopts the results from IRAS, that is, an albedo of 0.0497 and a diameter of 110.50 kilometers based on an absolute magnitude of 8.66.[13] The WISE team also published several alternative mean-diameters of (102.25±33.63 km), (106.289±1.633 km), (123.69±43.48 km), (125.664±33.78 km) and (139.146±33.78 km), with a corresponding albedo of (0.04±0.02), (0.0537±0.0138), (0.03±0.02), (0.0327±0.0263), and (0.027±0.013).[6][13]
On 28 March 2007, an asteroid occultation of Faïna gave a best-fit ellipse dimension of (132.0 km × 88.2 km) with a quality rating of 2, indicating its irregular, elongated shape. Another occultation on 21 October 2012, gave an ellipse of (125.0 km × 125.0 km). These timed observations are taken when the asteroid passes in front of a distant star.[6]
^ 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)