| Discovery[1] | |
|---|---|
| Discovered by | E. F. Helin |
| Discovery site | Palomar Obs. |
| Discovery date | 15 December 1990 |
| Designations | |
| (4957) Brucemurray | |
Named after | Bruce C. Murray[2] (American planetary scientist) |
| 1990 XJ | |
| NEO · Amor[1][3] Mars-crosser | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 41.35 yr (15,102 days) |
| Aphelion | 1.9082AU |
| Perihelion | 1.2228AU |
| 1.5655AU | |
| Eccentricity | 0.2189 |
| 1.96yr (715 days) | |
| 282.15° | |
| 0° 30m 11.52s / day | |
| Inclination | 35.011° |
| 254.90° | |
| 97.487° | |
| Earth MOID | 0.4258 AU · 165.9LD |
| Physical characteristics | |
| Dimensions | 3.01 km[4] 3.06 km[5] 3.11 km(calculated)[6] 3.499±0.095 km[7] |
| 2.892h[8][9] 2.8922 h[10] | |
| 0.132±0.023[7] 0.17[5] 0.18[4] 0.18±0.19[11] 0.20(assumed)[6] | |
| SMASS =S[1][6] · S[12] B–V =0.866±0.042[12] V–R =0.526±0.018[12] V–I =0.956±0.021[12] | |
| 14.9[1][6] · 15.1[5] · 15.10±0.3[7] | |
4957 Brucemurray, provisional designation1990 XJ, is a stonyasteroid, classified asnear-Earth object of theAmor group and asMars-crosser, approximately 3 kilometers in diameter. It was discovered by American astronomerEleanor Helin at thePalomar Observatory in California on 15 December 1990.[3] The asteroid was named after American planetary scientistBruce C. Murray.[2]
Brucemurray orbits the Sun at a distance of 1.2–1.9 AU once every 1 years and 12 months (715 days). Its orbit has aneccentricity of 0.22 and aninclination of 35° with respect to theecliptic.[1]
The body'sobservation arc begins with aprecovery taken at the AustralianSiding Spring Observatory in March 1976, or more than 14 years prior to its official discovery observation.[3]
This deepMars-crosser makes close approaches both to Earth and Mars. It has an Earthminimum orbital intersection distance of 0.4258 AU (63,700,000 km) which corresponds to 165.9lunar distances. On 18 May 2033, the asteroid will also pass 0.0684 AU (10,230,000 km) from Mars.[1]
In theSMASS classification,Brucemurray is a stonyS-type asteroid.[1] BVRIZ photometry also found that the asteroid is an S-type NEO.[12]
In the 1990s, two rotationallightcurves ofBrucemurray were obtained from photometric observations by Czech astronomerPetr Pravec atOndřejov Observatory. Lightcurve analysis gave arotation period of 2.892 hours in both cases with a brightness variation of 0.28 and 0.36magnitude, respectively (U=2/3).[8][9]
In 2004, an international study modeled a lightcurve with a concurring period of 2.8922 hours and found aspin axis of (358.0°, −50.0°) inecliptic coordinates (λ, β) (Q=3-).[10]
According to the survey carried out by theNEOWISE mission ofWide-field Infrared Survey Explorer and the ExploreNEOs survey using theSpitzer Space Telescope,Brucemurray measures between 3.01 and 3.499 kilometers in diameter and its surface has analbedo between 0.132 and 0.18.[4][5][7][11]
TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 3.11 kilometers based on anabsolute magnitude of 14.9.[6]
Thisminor planet was named after American planetary scientistBruce C. Murray (1931–2013), director of theJet Propulsion Laboratory, co-founder ofThe Planetary Society and professor atCalifornia Institute of Technology. This asteroid which comes close both to Mars and Earth, is considered a particularly appropriate object for Murray, who had diligently championed a mission to Mars.[2]
The official naming citation was published by theMinor Planet Center on 29 November 1993 (M.P.C. 22829).[13]
