_Mason-Dixon.png) Mason–Dixon modeled from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | E. Bowell |
| Discovery site | Anderson Mesa Stn. |
| Discovery date | 24 January 1982 |
| Designations | |
| (3131) Mason–Dixon | |
Named after | Charles Mason[1] Jeremiah Dixon (English astronomers) |
| 1982 BM1 · 1962 CK 1975 XS2 · 1977 DB3 1979 OS16 · 1979 QJ6 A922 DC | |
| main-belt[1][2] · (outer) Koronis[3][4][5] | |
| Orbital characteristics[2] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 63.82yr (23,311 d) |
| Aphelion | 3.0505AU |
| Perihelion | 2.7940 AU |
| 2.9222 AU | |
| Eccentricity | 0.0439 |
| 5.00 yr (1,825 d) | |
| 118.17° | |
| 0° 11m 50.28s / day | |
| Inclination | 2.4041° |
| 44.734° | |
| 147.18° | |
| Physical characteristics | |
| 14 km(est. at0.15)[6] | |
| 19.748±0.0537 h[7][8] | |
| 0.15(family albedo)[9] | |
| S(family based)[9] | |
| 12.0[1][2] | |
3131 Mason–Dixon (prov. designation:1982 BM1) is aKoronian asteroid from the outer regions of theasteroid belt. It was discovered on 24 January 1982, by American astronomerEdward Bowell at Lowell'sAnderson Mesa Station in Arizona, United States.[1] The likelyS-type asteroid has arotation period of 19.7 hours and measures approximately 14 kilometers (9 miles) in diameter.[7] It was named for English astronomersCharles Mason andJeremiah Dixon.[1]
Mason–Dixon is a core member of theKoronis family (605),[3][4][5] a very largeasteroid family of almost 6,000 known asteroids with nearly co-planar ecliptical orbits.[9] It orbits the Sun in theouter main-belt at a distance of 2.8–3.1 AU once every 5 years (1,825 days;semi-major axis of 2.92 AU). Its orbit has aneccentricity of 0.04 and aninclination of 2° with respect to theecliptic.[2]
The body was first observed atHeidelberg Observatory in February 1922. Itsobservation arc begins with aprecovery taken atPalomar Observatory in July 1954.[1] On 1 February 1907,Mason–Dixon made a close approach to one of the larger asteroids,52 Europa. At its closest, it passed Europa within 1.1 million kilometers.[citation needed]
Thisminor planet was named by the discoverer in memory of English astronomersCharles Mason (1728–1786) andJeremiah Dixon (1733–1779), who observed the1761 transit of Venus from the Cape of Good Hope. Between 1763 and 1767 they surveyed the so-calledMason–Dixon line, the boundary between the US States of Pennsylvania and Maryland. The officialnaming citation was published by theMinor Planet Center on 22 June 1986 (M.P.C. 10847).[10]
The asteroid'sspectral type has not been determined.[3] Due its membership to the stonyKoronis family,Mason–Dixon is likely a commonS-type asteroid.[9]: 23
In January 2012, a rotationallightcurve ofMason–Dixon was obtained fromphotometric observations by astronomers at thePalomar Transient Factory in California. Lightcurve analysis gave arotation period of19.748±0.0537 hours with a high brightness variation of 0.70magnitude (U=2), indicative of an elongated, non-spherical shape.[8] Another fragmentary lightcurve by Maurice Clark at Preston Gott Observatory in September 2014 gave a less accurate period of 10.20 hours with an amplitude of 0.75 magnitude.[11]
Assuming a typicalalbedo of 0.15 for members of the Koronis family,[9]: 23 Mason–Dixon measures 14 kilometers based on anabsolute magnitude of 12.00.[2][6] TheCollaborative Asteroid Lightcurve Link assumes an albedo of a carbonaceous asteroid of 0.057 and consequently calculates a larger diameter of 18.6 kilometers.[7]
