Discovered by Harvard College Obs. MPC designation 3401 Vanphilos Minor planet category Mars crosser Absolute magnitude 12.6 Asteroid group Mars-crosser asteroid | Discovery date 1 August 1981 Alternative names 1981 PA · 1946 DA Discovered 1 August 1981 Orbits Sun | |
Named after Vanessa Hall
Philip Osborne
(friends of G. V. Williams) Discoverer Harvard College Observatory Discovery site Harvard College Observatory, Oak Ridge Observatory People also search for 3267 Glo, 3040 Kozai, Sun | ||
3401 Vanphilos, provisional designation 1981 PA, is a stony asteroid, classified as an eccentric Mars-crosser, approximately 7 kilometers in diameter. It was discovered on 1 August 1981, by and at Harvard's Oak Ridge Observatory (Agassiz Station) in Massachusetts, United States.
In the SMASS taxonomy, Vanphilos is classified as a stony S-type asteroid. It orbits the Sun at a distance of 1.5–3.2 AU once every 3 years and 8 months (1,330 days). Its orbit has an eccentricity of 0.36 and an inclination of 22° with respect to the ecliptic. Vanphilos was first identified as 1946 DA from a precovery taken at Turku Observatory in 1946, extending the body's observation arc by 35 years prior to its official discovery at Harvard.
In February and March 2008, three rotational light-curves of Vanphilos were obtained from photometric observations by astronomers Petr Pravec, James Brinsfield and Robert Stephens. Light-curve analysis gave a well defined rotation period of 4.225 and 4.226 hours, respectively, with a change in brightness between 0.50 and 0.54 magnitude (U=3/3/3). In August 2014, astronomer Brian Warner derived a concurring period of 4.227 hours with an amplitude of 0.62 magnitude from his observations taken at the Palmer Divide Station in Colorado (U=3). Light-curve plots were published on-line by the Ondřejov Observatory and the Center for Solar System Studies.
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Vanphilos measures 7.02 and 7.10 kilometers in diameter, and its surface has an albedo of 0.377 and 0.31, respectively. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 10.30 kilometers, as the lower the body's albedo (reflectivity), the larger its diameter, at a constant absolute magnitude.
This minor planet was named for Vanessa Hall and Philip Osborne, by astronomer G. V. William to celebrate their marriage on 3 August 1991. Naming citation was published on 25 August 1991 (M.P.C. 18644).