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6247 Amanogawa, provisional designation 1990 WY3, is a background asteroid from the inner regions of the asteroid belt, approximately 7 kilometers (4 miles) in diameter. It was discovered on 21 November 1990, by Japanese amateur astronomers Kin Endate and Kazuro Watanabe at the Kitami Observatory.[1] The X-type asteroid has a rotation period of 12.38 hours.[6] It was named after the Amanogawa River on the island of Hokkaido, Japan.[1]

6247 Amanogawa
Discovery [1]
Discovered byK. Endate
K. Watanabe
Discovery siteKitami Obs.
Discovery date21 November 1990
MPC designation(6247) Amanogawa
Named after
Amanogawa River[1]
(Japanese river)
1990 WY3 · 1992 FR1
main-belt[1][2] · (inner)
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc27.45 yr (10,025 d)
Aphelion2.5286 AU
Perihelion2.2604 AU
2.3945 AU
3.71 yr (1,353 d)
0° 15m 57.6s / day
Physical characteristics
Mean diameter
6.722±0.098 km[4][5]
11.63 km (calculated)[6]
12.369±0.0107 h[7]
12.38±0.02 h[8]
0.057 (assumed)[6]
C (assumed)[6]
13.288±0.006 (R)[7]


Orbit and classificationEdit

Amanogawa is a non-family asteroid from the main belt's background population.[3] It orbits the Sun in the inner asteroid belt at a distance of 2.3–2.5 AU once every 3 years and 9 months (1,353 days; semi-major axis of 2.39 AU). Its orbit has an eccentricity of 0.06 and an inclination of 9° with respect to the ecliptic.[2] The body's observation arc begins with a precovery at Palomar Observatory on 14 November 1990, just one week prior to its official discovery observation at Kitami.[1]

Physical characteristicsEdit

In the SDSS-based taxonomy, Amanogawa has been characterized as an X-type asteroid.[9] It is also a generically assumed C-type asteroid.[6]

Rotation periodEdit

In September 2008, a rotational lightcurve of Amanogawa was obtained from photometric observations at the Oakley Southern Sky Observatory and Oakley Observatory. Lightcurve analysis gave a well-defined rotation period of 12.38 hours with a brightness variation of 0.48 magnitude (U=3).[8] In February 2014, astronomers at the Palomar Transient Factory measured a similar period of 12.369 hours and an amplitude of 0.38 magnitude in the R-band (U=2).[7]

Diameter and albedoEdit

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Amanogawa measures 6.722 kilometers in diameter and its surface has an albedo of 0.165.[4][5] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 11.63 kilometers based on an absolute magnitude of 13.4.[6]


This minor planet was named after the Japanese Amanogawa River that through the town of Kaminokuni on the island of Hokkaido. "Amanogawa" also means "Milky Way" in Japanese.[1] The official naming citation was published by the Minor Planet Center on 22 February 1997 (M.P.C. 29146).[10]


  1. ^ a b c d e f g "6247 Amanogawa (1990 WY3)". Minor Planet Center. Retrieved 28 May 2018.
  2. ^ a b c d "JPL Small-Body Database Browser: 6247 Amanogawa (1990 WY3)" (2018-04-26 last obs.). Jet Propulsion Laboratory. Retrieved 28 May 2018.
  3. ^ a b "Asteroid 6247 Amanogawa". Small Bodies Data Ferret. Retrieved 28 May 2018.
  4. ^ a b c Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68.
  5. ^ 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. (catalog)
  6. ^ a b c d e f g "LCDB Data for (6247) Amanogawa". Asteroid Lightcurve Database (LCDB). Retrieved 28 May 2018.
  7. ^ a b c Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75.
  8. ^ a b Carbo, Landy; Kragh, Katherine; Krotz, Jonathan; Meiers, Andrew; Shaffer, Nelson; Torno, Steven; et al. (July 2009). "Asteroid Lightcurve Analysis at the Oakley Southern Sky Observatory and Oakley Observatory: 2008 September and October". The Minor Planet Bulletin. 36 (3): 91–94. Bibcode:2009MPBu...36...91C. ISSN 1052-8091.
  9. ^ a b Carvano, J. M.; Hasselmann, P. H.; Lazzaro, D.; Mothé-Diniz, T. (February 2010). "SDSS-based taxonomic classification and orbital distribution of main belt asteroids". Astronomy and Astrophysics. 510: 12. Bibcode:2010A&A...510A..43C. doi:10.1051/0004-6361/200913322. Archived from the original on 2 May 2018. Retrieved 28 May 2018.
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 28 May 2018.

External linksEdit