| Discovery [1] | |
|---|---|
| Discovered by | Harvard College Obs. |
| Discovery site | Oak Ridge Obs. (Agassiz Stn.) |
| Discovery date | 1 August 1981 |
| Designations | |
| (3401) Vanphilos | |
Named after | Vanessa Hall Philip Osborne (friends of G. V. Williams) [2] |
| 1981 PA ·1946 DA | |
| Mars crosser [1] [3] [4] | |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 70.38 yr (25,708 days) |
| Aphelion | 3.2195 AU |
| Perihelion | 1.5147 AU |
| 2.3671 AU | |
| Eccentricity | 0.3601 |
| 3.64 yr (1,330 days) | |
| 264.28° | |
| 0° 16m 14.16s / day | |
| Inclination | 21.797° |
| 322.38° | |
| 108.64° | |
| Mars MOID | 0.1190 AU |
| Physical characteristics | |
| Dimensions | 7.023±1.045 km [5] 7.10±4.56 km [6] 10.30 km (calculated) [4] |
| 4.225±0.001 h [7] 4.226±0.001 h [8] 4.2261±0.0005 h [a] 4.227±0.005 h [9] | |
| 0.20 (assumed) [4] 0.31±0.15 [6] 0.377±0.198 [5] | |
| SMASS = S [1] · S [4] | |
| 12.29±0.27 [10] ·12.3 [1] [4] [5] ·12.65 [6] | |
3401 Vanphilos, provisional designation 1981 PA, is a stony, eccentric asteroid and sizeable 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. [3]
Vanphilos orbits the Sun in the inner main-belt 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. [1] In 1946, it was first identified as 1946 DA at the Finnish Turku Observatory, extending the body's observation arc by 35 years prior to its official discovery at Harvard. [3]
In the SMASS taxonomy, Vanphilos is characterized as a common S-type asteroid. [1]
In February and March 2008, three rotational lightcurves of Vanphilos were obtained from photometric observations by astronomers Petr Pravec, James W. 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 ). [7] [8] [a]
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 ). [9] Light-curve plots were published on-line by the Ondřejov Observatory and the Center for Solar System Studies. [b] [c]
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. [5] [6] 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. [4]
This minor planet was named for Vanessa Hall and Philip Osborne, by astronomer G. V. William to celebrate their marriage on 3 August 1991. [2] The approved naming citation was published by the Minor Planet Center on 25 August 1991 ( M.P.C. 18644). [11]
