1994 PC1 orbits the Sun at a distance of 0.9–1.8 AU once every 1 years and 7 months (572 days). Its orbit has an eccentricity of 0.33 and an inclination of 33° with respect to the ecliptic.[1]
On 17 January 1933, it passed 811,350 km (504,150 mi) from the Moon and then about an hour later made its closest known approach to Earth of 1,125,400 km (699,300 mi).[1] On 18 January 2022, it passed about 1,981,468 km (1,231,227 mi) from Earth.[1]
In 1998, a rotational lightcurve of 1994 PC1 was obtained from photometric observations by Petr Pravec. Lightcurve analysis gave a well-defined rotation period of 2.5999 hours with a brightness amplitude of 0.29 magnitude (U=3).[5]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, 1994 PC1 measures 1.052 kilometers in diameter and its surface has an albedo of 0.277.[3] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.20 and calculates a diameter of 1.30 kilometers based on an absolute magnitude of 16.8.[4]
2022 flyby
At 18 January 2022 21:51 UTC, 1994 PC1 passed 5.15 lunar distances from Earth[1] and had a 3-sigma uncertainty region of less than ± 50 km.[7] It peaked at an apparent magnitude of about 10[9] placing it just outside the reach of common 7×50 binoculars. The nearly Full moon being about 100 degrees from the asteroid during closest approach may have made it more difficult to observe with smaller telescopes.
(A) List includes near-Earth approaches of less than 5 lunar distances (LD) of objects with H brighter than 18. (B)Nominal geocentric distance from the Earth's center to the object's center (Earth radius≈0.017 LD). (C) Diameter: estimated, theoretical mean-diameter based on H and albedo range between X and Y. (D) Reference: data source from the JPL SBDB, with AU converted into LD (1 AU≈390 LD) (E) Color codes: unobserved at close approach observed during close approach upcoming approaches
^ abcdMainzer, A.; Grav, T.; Masiero, J.; Bauer, J.; Cutri, R. M.; McMillan, R. S.; et al. (November 2012). "Physical Parameters of Asteroids Estimated from the WISE 3-Band Data and NEOWISE Post-Cryogenic Survey". The Astrophysical Journal Letters. 760 (1): 6. arXiv:1210.0502. Bibcode:2012ApJ...760L..12M. doi:10.1088/2041-8205/760/1/L12. S2CID41459166.
