1036 Ganymed, provisional designation 1924 TD, is a stony asteroid on a highly eccentric orbit, classified as a near-Earth object of the Amor group. It was discovered by German astronomer Walter Baade at the Bergedorf Observatory in Hamburg on 23 October 1924, and named after Ganymede from Greek mythology.[1][2] With a diameter of approximately 35 kilometers (22 miles), Ganymed is the largest of all near-Earth objects but does not cross Earth's orbit. The S-type asteroid has a rotation period of 10.3 hours. In October 2024, it is predicted to approach Earth at a distance of 56,000,000 km; 35,000,000 mi (0.374097 AU).[15]

1036 Ganymed
Shape model of Ganymed from its lightcurve
Discovery[1]
Discovered byW. Baade
Discovery siteBergedorf Obs.
Discovery date23 October 1924
Designations
(1036) Ganymed
Pronunciation/ˈɡænəmɛd/
Named after
Ganymede[2]
(Greek mythology)
1924 TD · 1952 BF
1954 HH
Amor[1][3] · NEO
AdjectivesGanymedean /ɡænəˈmdiən/
Orbital characteristics[3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc93.69 yr (34,221 d)
Aphelion4.0837 AU
Perihelion1.2421 AU
2.6629 AU
Eccentricity0.5335
4.35 yr (1,587 d)
183.36°
0° 13m 36.48s / day
Inclination26.693°
215.55°
132.45°
Earth MOID0.3415 AU (133 LD)
Mars MOID0.03287 AU[1]
Physical characteristics
Dimensions39.3 km × 18.9 km[4]
Mean diameter
31.66±2.8 km[5]
35.01±0.78 km[6]
37.675±0.399 km[7][8][9]
10.297 h[10][11]
0.218[8][9]
0.243[6]
0.2926[5]
Tholen = S[4]
SMASS = S[4][10]
S[4][12][13]
U–B = 0.417[3]
B–V = 0.882±0.008[12]
V–R = 0.515±0.004[12]
V–I = 0.981±0.005[12]
9.45[1][3][5][6][8][9]
9.50[10][14]

Orbit and classification edit

 
Orbit of Ganymed (blue), with the inner planets and Jupiter (outermost).

Ganymed is an Amor asteroid, a subgroup of the near-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 1,587 days; semi-major axis of 2.66 AU). Its orbit has a high eccentricity of 0.53 and an inclination of 27° with respect to the ecliptic.[3] The body's observation arc begins at the discovering observatory on 24 October 1924 (99 years ago) (1924-10-24), the night after its official discovery observation.[1]

Close approaches edit

Earth approach edit

Ganymed has a minimum orbit intersection distance with Earth of 0.3415 AU (51,000,000 km), or 133 lunar distance. Its next pass of the Earth will be at a distance of 0.374097 AU (56,000,000 km; 34,800,000 mi) on 13 October 2024 (6 months' time) (2024-10-13).[15]

Mars approach edit

Due to the high eccentricity of its orbit, Ganymed is also a Mars-crosser, intersecting the orbit of the Red Planet at 1.66 AU. On 16 December 2176 (152 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]

Name edit

The minor planet of Ganymed was named after Ganymede from Greek mythology, using the German spelling ("Ganymed"). Ganymede was a Trojan prince abducted by Zeus to serve as a cup-bearer to the Greek gods. The name had previously also been given to Jupiter's third moon, "Ganymede", which was discovered in 1610 by Italian astronomer Galileo Galilei.[2]

Physical characteristics edit

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,[16] slightly brighter than the present value of 9.45.

Ganymed is a stony S-type asteroid, in the Tholen, SMASS and in the S3OS2 taxonomy. This means that it is relatively reflective and composed of iron and magnesium silicates. Spectral measurements put Ganymed in the S (VI) spectral subtype,[13] indicating a surface rich in orthopyroxenes, and possibly metals (although if metals are present they are covered and not readily apparent in the spectra).[13]

Diameter and albedo edit

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), Ganymed measures between 31.66 and 37.67 kilometers in diameter and its surface has an albedo between 0.218 and 0.293.[5][6][7][8][9]

The Collaborative Asteroid Lightcurve Link derives an albedo of 0.2809 and a mean-diameter of 31.57 kilometers based on an absolute magnitude of 9.50.[10] Carry published a diameter 34.28±1.38 kilometers in 2012.[17]

An occultation 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]

Rotation and poles edit

A large number of rotational lightcurves of Ganymed have been obtained from photometric observations since 1985.[18][19][20][14][21][22][23][24][25] Analysis of the best-rated lightcurves obtained by American photometrist Frederick Pilcher at his Organ Mesa Observatory (G50) in New Mexico during 2011 gave a rotation period of 10.297 hours with a consolidated brightness amplitude between 0.28 and 0.31 magnitude (U=3-/3/3).[10][11]

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 two spin axes of (214.0°, −73.0°), (190.0°, −78.0°), as well as (198.0°, −79.0°) in ecliptic coordinates (λ, β; L1/B1), respectively.[26][27][28]

In 1998, radar observations of Ganymed by the Arecibo 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]

References edit

  1. ^ a b c d e f "1036 Ganymed (1924 TD)". Minor Planet Center. Retrieved 29 August 2018.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1036) Ganymed". Dictionary of Minor Planet Names – (1036) Ganymed. Springer Berlin Heidelberg. p. 89. doi:10.1007/978-3-540-29925-7_1037. ISBN 978-3-540-00238-3.
  3. ^ a b c d e "JPL Small-Body Database Browser: 1036 Ganymed (1924 TD)" (2018-07-03 last obs.). Jet Propulsion Laboratory. Retrieved 29 August 2018.
  4. ^ a b c d e f "Asteroid 1036 Ganymed". Small Bodies Data Ferret. Retrieved 29 August 2018.
  5. ^ a b c d Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 12 March 2020.
  6. ^ a b c d Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)
  7. ^ a b Mainzer, A.; Grav, T.; Bauer, J.; Masiero, J.; McMillan, R. S.; Cutri, R. M.; et al. (December 2011). "NEOWISE Observations of Near-Earth Objects: Preliminary Results". The Astrophysical Journal. 743 (2): 17. arXiv:1109.6400. Bibcode:2011ApJ...743..156M. doi:10.1088/0004-637X/743/2/156. S2CID 239991.
  8. ^ a b c d Mainzer, A. K.; Bauer, J. M.; Cutri, R. M.; Grav, T.; Kramer, E. A.; Masiero, J. R.; et al. (June 2016). "NEOWISE Diameters and Albedos V1.0". NASA Planetary Data System: EAR-A-COMPIL-5-NEOWISEDIAM-V1.0. Bibcode:2016PDSS..247.....M. Retrieved 29 August 2018.
  9. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. S2CID 118700974. (catalog)
  10. ^ a b c d e "LCDB Data for (1036) Ganymed". Asteroid Lightcurve Database (LCDB). Retrieved 29 August 2018.
  11. ^ a b Pilcher, Frederick; Benishek, Vladimir; Briggs, John W.; Ferrero, Andrea; Klinglesmith, Daniel A. III; Warren, Curtis Alan (July 2012). "Eight Months of Lightcurves of 1036 Ganymed" (PDF). The Minor Planet Bulletin. 39 (3): 141–144. Bibcode:2012MPBu...39..141P. ISSN 1052-8091. Retrieved 29 August 2018.
  12. ^ a b c d Lin, Chien-Hsien; Ip, Wing-Huen; Lin, Zhong-Yi; Cheng, Yu-Chi; Lin, Hsing-Wen; Chang, Chan-Kao (March 2018). "Photometric survey and taxonomic identifications of 92 near-Earth asteroids". Planetary and Space Science. 152: 116–135. Bibcode:2018P&SS..152..116L. doi:10.1016/j.pss.2017.12.019.
  13. ^ a b c Fieber-Beyer, S. K.; Gaffey, M. J.; Abell, P. A.; Reddy, V. (March 2007). "Mineralogical Characterization of Near Earth Amor Asteroid 1036 Ganymed" (PDF). 38th Lunar and Planetary Science Conference. 1388 (1338): 1695. Bibcode:2007LPI....38.1695F. Retrieved 29 August 2018.
  14. ^ a b Hahn, 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. ISSN 0019-1035.
  15. ^ a b c "JPL Close-Approach Data: 1036 Ganymed (1924 TD)" (last observation: 2012-01-10). Retrieved 15 January 2012.
  16. ^ Putilin, J. (May 1931). "Brightness of the minor planet 1036 Ganymed". Astronomische Nachrichten. 242 (11): 213–216. Bibcode:1931AN....242..213P. doi:10.1002/asna.19312421104.
  17. ^ Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73 (1): 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009, S2CID 119226456 See Table 1.
  18. ^ 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.
  19. ^ 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. ISSN 0233-7665.
  20. ^ 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. ISSN 0320-930X.
  21. ^ 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. ISSN 1052-8091.
  22. ^ Velichko, F. P.; Magnusson, P. (March 2012). "Photometry and Polarimetry of the Largest NEA 1036 Ganymed". Astronomicheskii Tsirkulyar. 1575: 1–2. Bibcode:2012ATsir1575....1V.
  23. ^ Velichko, F. P.; Psarev, V. A.; Kiselev, N. N.; Zaitsev, S. V.; Velichko, S. F.; Krymsaljuk, R. Yu. (March 2013). "Photometry and Polarimetry of Largest NEA 1036 Ganymed" (PDF). 44th Lunar and Planetary Science Conference (1719): 2372. Bibcode:2013LPI....44.2372V. Retrieved 29 August 2018.
  24. ^ Warner, Brian D. (October 2015). "Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2015 March–June". The Minor Planet Bulletin. 42 (4): 256–266. Bibcode:2015MPBu...42..256W. ISSN 1052-8091. PMC 7244091. PMID 32455361.
  25. ^ Behrend, Raoul. "Asteroids and comets rotation curves – (1036) Ganymed". Geneva Observatory. Retrieved 29 August 2018.
  26. ^ Kaasalainen, M.; Torppa, J.; Piironen, J. (October 2002). "Models of Twenty Asteroids from Photometric Data". Icarus. 159 (2): 369–395. Bibcode:2002Icar..159..369K. doi:10.1006/icar.2002.6907.
  27. ^ Hanus, J.; Delbo', M.; Durech, J.; Alí-Lagoa, V. (August 2015). "Thermophysical modeling of asteroids from WISE thermal infrared data - Significance of the shape model and the pole orientation uncertainties". Icarus. 256: 101–116. arXiv:1504.04199. Bibcode:2015Icar..256..101H. doi:10.1016/j.icarus.2015.04.014. S2CID 118480799.
  28. ^ Viikinkoski, M.; Hanus, J.; Kaasalainen, M.; Marchis, F.; Durech, J. (November 2017). "Adaptive optics and lightcurve data of asteroids: twenty shape models and information content analysis". Astronomy and Astrophysics. 607: 14. arXiv:1708.05191. Bibcode:2017A&A...607A.117V. doi:10.1051/0004-6361/201731456. S2CID 67813915.
  29. ^ "1036 Ganymed Radar Images".
  30. ^ a b Nakayama, 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.

Further reading edit

External links edit