| Discovery[1] | |
|---|---|
| Discovered by | E. F. Helin |
| Discovery site | Palomar Obs. |
| Discovery date | 17 October 1974 |
| Designations | |
| (2074) Shoemaker | |
Named after | Eugene Shoemaker (American astronomer)[2] |
| 1974 UA | |
| Mars-crosser[3][4] · Hungaria[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 63.23 yr (23,096 days) |
| Aphelion | 1.9472AU |
| Perihelion | 1.6521 AU |
| 1.7996 AU | |
| Eccentricity | 0.0820 |
| 2.41yr (882 days) | |
| 243.44° | |
| 0° 24m 29.88s / day | |
| Inclination | 30.080° |
| 207.29° | |
| 205.58° | |
| Earth MOID | 0.6680 AU · 260.2LD |
| Physical characteristics | |
| Dimensions | 3.18±0.51 km[5] 3.217±0.558 km[1][6] 4.93 km(calculated)[3] |
| 2.5328±0.0004 h[7] 2.5331±0.0002 h[a][b] 2.5338±0.0002h[8] 2.534±0.001 h[9] 2.809±0.001 h[10][c] 2.82±0.01 h[11] 57.02±0.10 h[12] | |
| 0.20(assumed)[3] 0.41±0.13[5] 0.518±0.211[6] | |
| SMASS = Sa[1] · S[3] | |
| 13.80[6] · 13.9[1][3] · 14.24[5] · 14.28±0.36[13] | |
2074 Shoemaker, provisional designation1974 UA, is a stony Hungariaasteroid,Mars-crosser and suspected synchronousbinary system from the innermost regions of theasteroid belt, approximately 4 kilometers in diameter. It was discovered on 17 October 1974, by astronomerEleanor Helin at thePalomar Observatory.[4] She named it after American astronomerEugene Shoemaker.[2]
Shoemaker is a bright member of the dynamicalHungaria group that forms the innermost dense concentration of asteroids in theSolar System.[3] It orbits the Sun in theinner main-belt at a distance of 1.7–1.9 AU once every 2 years and 5 months (882 days). Its orbit has aneccentricity of 0.08 and aninclination of 30° with respect to theecliptic.[1] With aperihelion of 1.6521 AU,Shoemaker is aMars-crossing asteroid as it crosses the orbit ofMars at 1.666 AU.[1]
The body'sobservation arc begins with aprecovery taken at Palomar in April 1954, more than 20 years prior to its official discovery observation.[4]
In theSMASS classification,Shoemaker is a Sa-subtype, that transitions form the common stonyS-type asteroids to theA-type asteroids.[1]
Several rotationallightcurve ofShoemaker were obtained from photometric observations by American astronomerBrian Warner at his Palmer Divide Observatory (716) and CS3-Station (U82). Analysis of the best-rated lightcurves gave a well-definedrotation period of 2.5328 hours with a brightness amplitude of 0.13magnitude (U=3).[7][8][a]
In October 2003, photometric observations ofShoemaker byRobert D. Stephens gave a long rotation period of 57.02 hours.[12] After re-measuring the images with newer software and calibration techniques, two mutual occultation and eclipsing events were found, indicating thatShoemaker might be a synchronousbinary asteroid with aminor-planet moon orbiting it every 55 hours.[7] Observations in 2010, were difficult due to incomplete coverage and gave an orbital period of 27.39 hours for the secondary.[8] Observations by astronomers at Etscorn Campus Observatory (719) in 2015, did not mention any mutual events.[9]
In June 2017, Warner measured a rotation period of2.5331±0.0002 hours and an orbital period for the secondary of 44.28 hours at his CS3-Palmer Divide Station in California.[a][b] The binary nature ofShoemaker remains unconfirmed.
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Shoemaker measures 3.18 and 3.22 kilometers in diameter and its surface has analbedo between 0.41 and 0.52, respectively.[5][6] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 4.93 kilometers based on anabsolute magnitude of 13.9.[3]
Thisminor planet was named by the discoverer after her colleague, the American astronomerEugene Shoemaker (1928–1997), who was adiscoverer of minor planets and of theComet Shoemaker–Levy 9 that collided with Jupiter. He is well known for his work onimpact craters and his role in the lunarRanger,Surveyor andApollo programs.[2]
The naming was also proposed byBrian G. Marsden, the director of theMinor Planet Center (MPC).[2] The officialnaming citation was published by theMinor Planet Center on 1 November 1978 (M.P.C. 4548).[14]
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