| Discovery[1] | |
|---|---|
| Discovered by | C. Shoemaker |
| Discovery site | Palomar Obs. |
| Discovery date | 13 May 1985 |
| Designations | |
| (4085) Weir | |
Named after | Doris Blackman Weir[2][3] (American geologist) |
| 1985 JR · 1981 JY 1982 XK | |
| main-belt · (middle)[4] Eunomia[5] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 36.57 yr (13,356 days) |
| Aphelion | 2.8838AU |
| Perihelion | 2.3288 AU |
| 2.6063 AU | |
| Eccentricity | 0.1065 |
| 4.21yr (1,537 days) | |
| 261.69° | |
| 0° 14m 3.12s / day | |
| Inclination | 14.220° |
| 68.681° | |
| 136.29° | |
| Physical characteristics | |
| Dimensions | 9.221±0.241 km[6] 9.579±0.048 km[7] 9.66±0.77 km[8] 11.30 km(calculated)[4] |
| 14.602±0.005h[9][a] 14.657±0.0046 h[10] | |
| 0.20(assumed)[4] 0.228±0.038[8] 0.2334±0.0274[7] 0.273±0.060[6] | |
| S (Tholen)[4] | |
| 12.025±0.001(R)[10] · 12.1[1][4] · 12.30[7][8] · 12.38±0.22[11] | |
4085 Weir, provisional designation1985 JR, is a stony Eunomianasteroid from the central regions of theasteroid belt, approximately 10 kilometers in diameter. It was discovered on 13 May 1985, by astronomerCarolyn Shoemaker at thePalomar Observatory in California, United States. The asteroid was named after American geologist Doris Blackman Weir.[2][3]
Weir is a member of theEunomia family (502),[5] a prominentfamily of stonyS-type asteroid and the largest one in the intermediate main belt with more than 5,000 members.[12]: 23 It orbits the Sun in thecentral main-belt at a distance of 2.3–2.9 AU once every 4 years and 3 months (1,537 days;semi-major axis of 2.61 AU). Its orbit has aneccentricity of 0.11 and aninclination of 14° with respect to theecliptic.[1]
The body'sobservation arc begins with its first observation as1981 JY atAnderson Mesa Station in May 1981, or four years prior to its official discovery observation at Palomar.[2]
In theTholen classification,Weir is a common, stonyS-type asteroid,[4] which is also the overallspectral type for members of the Eunomia family.[12]: 23
In May 2006, a rotationallightcurve ofWeir was obtained from photometric observations byBrian Warner at hisPalmer Divide Observatory in Colorado. Lightcurve analysis gave arotation period of 14.602 hours with a brightness variation of 0.18magnitude (U=2).[9][a] A concurring period of 14.657 hours and an amplitude of 0.24 magnitude was measured by astronomers at thePalomar Transient Factory in May 2010 (U=2).[10]
According to the surveys carried out by the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Weir measures between 9.221 and 9.66 kilometers in diameter and its surface has analbedo between 0.228 and 0.273.[6][7][8]
TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 11.30 kilometers based on anabsolute magnitude of 12.1.[4]
Thisminor planet was named after Americanplanetary geologist with theUnited States Geological Survey, Doris Blackman Weir.[2][3] The approved naming citation was published by theMinor Planet Center on 12 December 1989 (M.P.C. 15576).[13]
