1999 FH orbits the Sun at a distance of 1.7–3.0 AU once every 3 years and 7 months (1,309 days). Its orbit has an eccentricity of 0.29 and an inclination of 12° with respect to the ecliptic.[1] A first precovery was taken at Steward Observatory in 1992, extending the body's observation arc by 7 years prior to its official discovery observation.[2]
Physical characteristics
SDSS photometry characterized 1999 FH as a rare and reddish L-type, which belong to the larger complex of stony asteroids.[7]
Slow rotator and tumbler
In September 2014, American astronomer Robert Stephens obtained a rotational lightcurve from photometric observations taken at the Center for Solar System Studies (CS3, U81) in California.[a] It gave an exceptionally long rotation period of 990±50 hours with a brightness amplitude of 0.55 magnitude (U=2), which makes it one of the slowest rotators known to exist. It is also a suspected tumbling asteroid, which show a non-principal axis rotation.[6]
Diameter and albedo
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, 1999 FH measures 3.395 and 4.17 kilometers in diameter and its surface has an albedo of 0.287 and 0.176, respectively.[4] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 3.92 kilometers with an absolute magnitude of 14.4.[3]