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 | 1.9472 AU |
Perihelion | 1.6521 AU |
1.7996 AU | |
Eccentricity | 0.0820 |
2.41 yr (882 days) | |
243.44 ° | |
0° 24m 29.88s / day | |
Inclination | 30.080° |
207.29° | |
205.58° | |
Earth MOID | 0.6680 AU · 260.2 LD |
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±0.0002 h [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 designation 1974 UA, is a stony Hungaria asteroid, Mars-crosser and suspected synchronous binary system from the innermost regions of the asteroid belt, approximately 4 kilometers in diameter. It was discovered on 17 October 1974, by astronomer Eleanor Helin at the Palomar Observatory. [4] She named it after American astronomer Eugene Shoemaker. [2]
Shoemaker is a bright member of the dynamical Hungaria group that forms the innermost dense concentration of asteroids in the Solar System. [3] It orbits the Sun in the inner main-belt at a distance of 1.7–1.9 AU once every 2 years and 5 months (882 days). Its orbit has an eccentricity of 0.08 and an inclination of 30 ° with respect to the ecliptic. [1] With a perihelion of 1.6521 AU, Shoemaker is a Mars-crossing asteroid as it crosses the orbit of Mars at 1.666 AU. [1]
The body's observation arc begins with a precovery taken at Palomar in April 1954, more than 20 years prior to its official discovery observation. [4]
In the SMASS classification, Shoemaker is a Sa-subtype, that transitions form the common stony S-type asteroids to the A-type asteroids. [1]
Several rotational lightcurve of Shoemaker were obtained from photometric observations by American astronomer Brian Warner at his Palmer Divide Observatory ( 716) and CS3-Station ( U82). Analysis of the best-rated lightcurves gave a well-defined rotation period of 2.5328 hours with a brightness amplitude of 0.13 magnitude ( U=3). [7] [8] [a]
In October 2003, photometric observations of Shoemaker by Robert 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 that Shoemaker might be a synchronous binary asteroid with a minor-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 of 2.5331±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 of Shoemaker remains unconfirmed.
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Shoemaker measures 3.18 and 3.22 kilometers in diameter and its surface has an albedo between 0.41 and 0.52, respectively. [5] [6] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 4.93 kilometers based on an absolute magnitude of 13.9. [3]
This minor planet was named by the discoverer after her colleague, the American astronomer Eugene Shoemaker (1928–1997), who was a discoverer of minor planets and of the Comet Shoemaker–Levy 9 that collided with Jupiter. He is well known for his work on impact craters and his role in the lunar Ranger, Surveyor and Apollo programs. [2]
The naming was also proposed by Brian G. Marsden, the director of the Minor Planet Center (MPC). [2] The official naming citation was published by the Minor Planet Center on 1 November 1978 ( M.P.C. 4548). [14]
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