Ganymed is anAmor asteroid, a subgroup of thenear-Earth asteroids that approach the orbit of Earth from beyond, but do not cross it. It orbits the Sun at a distance of 1.2–4.1 AU about once every 4 years and 4 months (i.e., 52 months or 1,589 days;semi-major axis of 2.66 AU). Its orbit has a higheccentricity of 0.53 and aninclination of 27° with respect to theecliptic.[3]
Due to the high eccentricity of its orbit, Ganymed is also aMars-crosser, intersecting the orbit of the Red Planet. On 16 December 2176 (151 years' time) (2176-12-16), it will pass at a distance of 0.02868 AU (4,290,000 km; 2,670,000 mi) from Mars.[15]
Owing to its early discovery date, Ganymed has a rich observational history. A 1931 paper published theabsolute magnitude, based on observations to date, as 9.24,[16] slightly brighter than the present value of 9.45.
Ganymed is a stonyS-type asteroid, in theTholen,SMASS and in theS3OS2 taxonomy. This means that it is relatively reflective and composed of iron andmagnesiumsilicates. Spectral measurements put Ganymed in the S (VI) spectral subtype,[13] indicating a surface rich inorthopyroxenes, and possibly metals (although if metals are present they are covered and not readily apparent in the spectra).[13]
TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.2809 and a mean-diameter of 31.57 kilometers based on anabsolute magnitude of 9.50.[10] Carry published a diameter34.28±1.38 kilometers in 2012.[17]
Anoccultation of a star by Ganymed was observed from California on 22 August 1985.[4] Additional observations in 2011 gave an occultation cross-section with a semi-major and minor axis of 39.3 and 18.9 kilometers, respectively.[4]
Three studies using modeled photometric data from the Uppsala Asteroid Photometric Catalogue, WISE thermal infrared data and other sources, gave a concurring period of 10.313, 10.31284, and 10.31304 hours, respectively. Each modeled lightcurve also determined twospin axes of (214.0°, −73.0°), (190.0°, −78.0°), as well as (198.0°, −79.0°) inecliptic coordinates (λ, β; L1/B1), respectively.[26][27][28]
In 1998, radar observations of Ganymed by theArecibo radio telescope produced images of the asteroid, revealing a roughly spherical object.[29] Polarimetric observations conducted by Japanese astronomers concluded that there was a weak correlation between the object's light- and polarimetry curve as a function of rotation angle.[30] Because polarization is dependent 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.[30]
^abHahn, G.; Magnusson, P.; Harris, A. W.; Young, J. W.; Belkora, L. A.; Fico, N. J.; et al. (April 1989). "Physical studies of Apollo-Amor asteroids - UBVRI photometry of 1036 Ganymed and 1627 Ivar".Icarus.78 (2):363–381.Bibcode:1989Icar...78..363H.doi:10.1016/0019-1035(89)90184-X.ISSN0019-1035.
^Harris, A. W.; Young, J. W. (June 1985). "Photometric Results for Earth Approaching Asteroids".Bulletin of the American Astronomical Society.17: 726.Bibcode:1985BAAS...17R.726H.
^Lupishko, D. F.; Velichko, F. P.; Kazakov, V. V.; Shevchenko, V. G. (February 1987). "The asteroid 1036 Ganymede - Light curves, period, and sense of rotation".Kinematika I Fizika Nebesnykh Tel.3: 92.Bibcode:1987KFNT....3...92L.ISSN0233-7665.
^Lupishko, D. F.; Velichko, F. P.; Shevchenko, V. G. (June 1988). "Photometry of the AMOR type asteroids 1036 Ganymede and 1139 Atami".Astronomicheskii Vestnik.22: 167–173.InRussian.Bibcode:1988AVest..22..167L.ISSN0320-930X.
^Skiff, Brian A.; Bowell, Edward; Koehn, Bruce W.; Sanborn, Jason J.; McLelland, Kyle P.; Warner, Brian D. (July 2012). "Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS) - 2008 May through 2008 December".The Minor Planet Bulletin.39 (3):111–130.Bibcode:2012MPBu...39..111S.ISSN1052-8091.
^Velichko, F. P.; Magnusson, P. (March 2012). "Photometry and Polarimetry of the Largest NEA 1036 Ganymed".Astronomicheskii Tsirkulyar.1575:1–2.Bibcode:2012ATsir1575....1V.
^abNakayama, Hiroyuki; Fujii, Yasumasa; Ishiguro, Masateru; Nakamura, Ryosuke; Yokogawa, Sozo; Yoshida, Fumi; et al. (July 2000). "Observations of Polarization and Brightness Variations with the Rotation for Asteroids 9 Metis, 52 Europa, and 1036 Ganymed".Icarus.146 (1):220–231.Bibcode:2000Icar..146..220N.doi:10.1006/icar.2000.6396.
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