3401 Vanphilos
Mars-crossing asteroid
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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]
| 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] | |
Orbit and classification
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]
Physical characteristics
In the SMASS taxonomy, Vanphilos is characterized as a common S-type asteroid.[1]
Rotation period
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]
Diameter and albedo
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]
Naming
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]
Notes
- Pravec (2008) web: rotation period 4.2261±0.0005 hours with a brightness amplitude of 0.51 mag and quality code of 3. Summary figures for (3401) Vanphilos at Collaborative Asteroid Lightcurve Link (CALL) and Pravec, P.; Wolf, M.; Sarounova, L. (2008) at Ondřejov Observatory
- Online published Lightcure plots of (3401) Vanphilos at the Center for Solar System Studies (CS3) in 2014
- Online published lightcure plot of (3401) Vanphilos at Ondřejov Observatory in 2008
