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Discovery
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| Discovered by | W. Baade |
| Discovery date | October 23, 1924 |
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Designations
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| Named after | Ganymede |
| Alternate name(s) | 1924 TD; 1952 BF; 1954 HH |
| Minor planet category |
Amor, Mars-crosser asteroid |
| Epoch October 22, 2004 (JD 2453300.5) |
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| Aphelion | 4.091 AU (611.961 Gm) |
| Perihelion | 1.233 AU (184.434 Gm) |
| Semi-major axis | 2.662 AU (398.198 Gm) |
| Eccentricity | 0.537 |
| Orbital period | 4.34 a (1586.202 d) |
| Average orbital speed | 16.86 km/s |
| Mean anomaly | 152.459° |
| Inclination | 26.644° |
| Longitude of ascending node | 215.699° |
| Argument of perihelion | 132.429° |
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Physical characteristics
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| Dimensions | 31.7 km |
| Mass | 3.3×1016 kg |
| Mean density | 2.0 g/cm³ |
| Equatorial surface gravity | 0.0089 m/s² |
| Escape velocity | 0.0168 km/s |
| Rotation period | 10.31 h [1] |
| Albedo | 0.17 [2] |
| Temperature | ~160 K |
| Spectral type | S (VI) [3][4] |
| Apparent magnitude | 8.1 [5] |
| Absolute magnitude (H) | 9.45 |
1036 Ganymed ( /ˈɡænɨmɛd/) is the largest Amor asteroid, at about 32 km in diameter.[3] It was discovered by Walter Baade on October 23, 1924, and is named after Ganymede, the Trojan prince turned god whom Zeus designated the cupbearer to the Greek gods (Jupiter's moon Ganymede is also named after that individual). It has a very well determined orbit, and its next pass of the Earth will be at a distance of 0.359104 AU (53,721,200 km; 33,380,800 mi) on 2011-Oct-13.[6] It is also a Mars-crosser asteroid, and will pass 0.02868 AU (4,290,000 km; 2,666,000 mi) from Mars on 2176-Dec-16.[6]
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Owing to its early discovery date, Ganymed has a rich observational history. A 1931 paper published the absolute magnitude, based on observations to date, as 9.24,[7] slightly brighter than the present value of 9.45. Ganymed is an S-type asteroid, meaning that it is relatively reflective and composed of iron- and magnesium-silicates. Spectral measurements put Ganymed in the S (VI) spectral subtype, indicating a surface rich in orthopyroxenes, and possibly metals (although if metals are present they are covered and not readily apparent in the spectra).[3]
In 1998, radar observations of Ganymed by the Arecibo radio telescope produced images of the asteroid, revealing a roughly spherical object.[8] Also around this time a study of several asteroids' visual lightcurve and polarization curves was conducted (the data for Ganymed is limited due to poor weather at the time). The study concluded that there was a weak correlation between the lightcurve and polarimetry curve as a function of rotation angle.[9] Because polarization is dependant on surface terrain and composition, rather than the observed size of the object like the lightcurve, this suggests that the surface features of the asteroid are roughly uniform over its observed surface.[9]
More recent observations of Ganymed's lightcurve, reported in 2007, confirm a rotation period of 10.314 ± 0.004 h and a lightcurve amplitude of 0.12 mag.[10]
One occultation of a star by Ganymed was observed from California on August 22, 1985.
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