4197 Morpheus

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4197 Morpheus
Discovery [1]
Discovered by E. F. Helin
E. Shoemaker
Discovery site Palomar Obs.
Discovery date 11 October 1982
MPC designation 4197 Morpheus
Named after
(mythology and movie)[2]
1982 TA
Apollo · NEO
Orbital characteristics[1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc 61.98 yr (22,639 days)
Aphelion 4.0691 AU
Perihelion 0.5245 AU
2.2968 AU
Eccentricity 0.7716
3.48 yr (1,271 days)
0° 16m 59.52s / day
Inclination 12.577°
Earth MOID 0.0988 AU
Physical characteristics
Dimensions 1.8 km (dated)[1]
2.20 km (dated)[3]
2.98 km (taken)[4]
2.981 km[5]
3.043±0.156 km[6]
3.5372 h[7]
3.5380 h[8]
3.5387 h[9]
3.540±0.001 h[10]
3.560 h[11]
SMASS = Sq [1] · S[4]
14.6[1][6] · 14.8[3][4][5][10] · 14.88[8]

4197 Morpheus, provisional designation 1982 TA, is an extremely eccentric stony asteroid and near-Earth object from to the subgroup of Apollo asteroids, about 3 kilometers in diameter. It was discovered by American astronomers Eleanor Helin and Eugene Shoemaker at the U.S. Palomar Observatory, California, on 11 October 1982.[2]

The asteroid orbits the Sun at a distance of 0.5–4.1 AU once every 3 years and 6 months (1,271 days). Its orbit has an eccentricity of 0.77 and an inclination of 13° with respect to the ecliptic.Due to this elongated orbit, the asteroid is both, a Mars-crosser and a Venus-crosser. Its minimum orbit intersection distance with Earth is 0.0983 AU (14,700,000 km).[1] The first precovery was taken at the discovering observatory in 1954, extending the asteroid's observation arc by 28 years prior to its discovery.[2]

On the SMASS taxonomic scheme, the stony S-type asteroid is classified as a Sq sub-type, which transitions to the rather rare Q-type. According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, it measures about 3.0 kilometers in diameter and its surface has a relatively high albedo of 0.28.[6]

The asteroid has a well-defined rotation period of 3.54 hours. In 1996 during the body's close approach to Earth within 0.1 AU, a photometric light-curve analysis performed by Czech astronomer Petr Pravec at the Ondřejov Observatory gave a period of 3.5380 hours with a brightness amplitude of 0.49 in magnitude (U=3). At the same time, astronomers at the Goldstone Observatory analysed it using radar delay-Doppler imaging. The resultant images are not very clear, but they show that the body has a roughly triangular shape, and a 3-hour rotation period.[citation needed] Seven years later, during the asteroid's next close approach in 2003, it was observed for five nights by Slovak astronomer Adrián Galád at the Modra Observatory. The light-curve rendered a period of 3.5387 hours and an amplitude of 0.4 in magnitude (U=3).[9]

The minor planet is named after Morpheus from Greek mythology. He is a god of dreams who appears in the poem Metamorphoses written by the Roman poet Ovid. He is capable to imitate any human form and to appear in dreams. It is also the name of one of the characters in the franchise The Matrix.[2] Naming citation was published on 5 January 2015 (M.P.C. 91790).[12]


  1. ^ a b c d e f "JPL Small-Body Database Browser: 4197 Morpheus (1982 TA)" (2016-08-27 last obs.). Jet Propulsion Laboratory. Retrieved 5 December 2016. 
  2. ^ a b c d "4197 Morpheus (1982 TA)". Minor Planet Center. Retrieved 1 March 2016. 
  3. ^ a b c Harris, Alan W. (February 1998). "A Thermal Model for Near-Earth Asteroids". Icarus. 131 (2): 291–301. Bibcode:1998Icar..131..291H. doi:10.1006/icar.1997.5865. Retrieved 1 March 2016. 
  4. ^ a b c d "LCDB Data for (4197) Morpheus". Asteroid Lightcurve Database (LCDB). Retrieved 25 May 2016. 
  5. ^ a b c Pravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus. 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026. Retrieved 1 March 2016. 
  6. ^ 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:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 25 May 2016. 
  7. ^ Prokof'eva, V. V.; Gaftonyuk, N. M.; Tarashchuk, V. P. (September 2001). "Three Periods in Asteroid 4197 Brightness Variations". Solar System Research (5): 383–389. Bibcode:2001SoSyR..35..383P. Retrieved 1 March 2016. 
  8. ^ a b Pravec, P.; S˘ arounová, L.; Wolf, M.; Ferrin, I. R. Vasquez; Zhu, J. (January 2000). "CCD photometry of asteroids (4197) 1982 TA and 1997 LY 4". Planetary and Space Science. 48 (1): 59–65. Bibcode:2000P&SS...48...59P. doi:10.1016/S0032-0633(99)00073-2. Retrieved 1 March 2016. 
  9. ^ a b Galád, A.; Kornos, L.; Gajdos, S.; Világi, J.; Tóth, J. (October 2004). "Relative photometry of numbered asteroids (3712), (4197), (5587), (28753) and (66063)". Contributions of the Astronomical Observatory Skalnaté Pleso: 157–166. Bibcode:2004CoSka..34..157G. Retrieved 1 March 2016. 
  10. ^ a b Wisniewski, W. Z.; Michalowski, T. M.; Harris, A. W.; McMillan, R. S. (March 1995). "Photoelectric Observations of 125 Asteroids". Abstracts of the Lunar and Planetary Science Conference. Bibcode:1995LPI....26.1511W. Retrieved 1 March 2016. 
  11. ^ Hoffmann, Martin; Rebhan, Helge; Neukum, Gerhard; Geyer, Edward H. (January 1993). "Photometric observations of four near-earth asteroids". Acta Astronomica: 61–67. Bibcode:1993AcA....43...61H. ISSN 0001-5237. Retrieved 1 March 2016. 
  12. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 25 May 2016. 

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