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2478 Tokai

Topic: Astronomy

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2478 Tokai
Discovery[1]
Discovered byT. Furuta
Discovery siteTōkai Obs. (879)
Discovery date4 May 1981
Designations
(2478) Tokai
Pronunciation/ˈtoʊkaɪ/
ja
Named afterTōkai (Japanese city)[2]
1981 JC · 1931 HH
1932 SE · 1934 ED
1939 VH · 1951 JP
1955 OE · 1955 QV
1957 BD · 1972 RS
1978 NU2 · 1979 XR
1981 JT
Minor planet categorymain-belt · Flora[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc84.68 yr (30,929 days)
|{{{apsis}}}|helion}}2.3781 AU
|{{{apsis}}}|helion}}2.0740 AU
2.2261 AU
Eccentricity0.0683
Orbital period3.32 yr (1,213 days)
Mean anomaly103.28°
Mean motion0° 17m 48.48s / day
Inclination4.1389°
Longitude of ascending node228.80°
233.85°
Known satellites1[3][4][5]
Physical characteristics
Dimensions9.238±0.112 km[6]
9.36±1.51 km[7]
9.71±0.49 km[8]
9.982±0.031 km[9]
10.087 km[10]
10.09 km (taken)[3]
Rotation period25.88±0.01 h[lower-alpha 1]
25.885±0.007 h[11]
25.8913 h[lower-alpha 2]
25.97±0.11 h[12]
Geometric albedo0.144±0.015[8]
0.1957[10]
0.2084±0.0371[9]
0.252±0.045[6]
0.33±0.20[7]
SMASS = S[1] · S[3]
Absolute magnitude (H)11.88±0.03 (R)[lower-alpha 2] · 12.00[7] · 12.15±0.04[13] · 12.2[1] · 12.33[9] · 12.37±0.058[3][10] · 12.80[8]


2478 Tokai, provisionally designated 1981 JC, is a stony Florian asteroid and binary system from the inner regions of the asteroid belt, approximately 10 kilometers in diameter. It was discovered on 4 May 1981, by Japanese astronomer Toshimasa Furuta at Tōkai Observatory (879), Japan.[14] The asteroid was named after the city of Tōkai.[2]

Orbit and classification

Tokai is a member of the Flora family, one of the largest groups of stony asteroids in the main-belt. It orbits the Sun in the inner main-belt at a distance of 2.1–2.4 AU once every 3 years and 4 months (1,213 days). Its orbit has an eccentricity of 0.07 and an inclination of 4° with respect to the ecliptic.[1]

Physical characteristics

In the SMASS classification, Tokai is a common S-type asteroid.[1]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer (WISE) with its subsequent NEOWISE mission, Tokai measures between 9.238 and 9.982 kilometers in diameter and its surface has an albedo between 0.144 and 0.33.[6][7][8][9] The Collaborative Asteroid Lightcurve Link agrees with Petr Pravec's revised WISE-data, that is, an albedo of 0.1957 and a diameter of 10.09 kilometers with an absolute magnitude of 12.37.[3]

Satellite

Photometric observations in 2007, revealed a minor-planet moon in orbit of Tokai. It measures approximately 6 kilometers in diameter (lower limit diameter ratio of 0.72) and has an orbital period of 25.88 hours.[3][4][5]

Naming

This minor planet was named after the city of Tōkai, Japan, where the discoverer lives and the discovering observatory is located.[2] The approved naming citation was published by the Minor Planet Center on 8 February 1982 (M.P.C. 6650).[15]

Notes

  1. ↑ Oey (2011) web: rotation period 25.88 hours with a brightness amplitude of mag. Summary figures for (2478) Tokai at Collaborative Asteroid Lightcurve Link (CALL)
  2. ↑ 2.0 2.1 Pravec (2007) web: rotation period 25.8913 hours with a brightness amplitude of 0.41 mag. Q=3. Summary figures for (2478) Tokai at Collaborative Asteroid Lightcurve Link (CALL)

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 "JPL Small-Body Database Browser: 2478 Tokai (1981 JC)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2002478. Retrieved 18 June 2017. 
  2. ↑ 2.0 2.1 2.2 Schmadel, Lutz D. (2007). "(2478) Tokai". Dictionary of Minor Planet Names – (2478) Tokai. Springer Berlin Heidelberg. p. 202. doi:10.1007/978-3-540-29925-7_2479. ISBN 978-3-540-00238-3. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 "LCDB Data for (2478) Tokai". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=2478%7CTokai. Retrieved 18 June 2017. 
  4. ↑ 4.0 4.1 "Electronic Telegram No. 824". IAU Central Bureau for Astronomical Telegrams. 2007-01-30. http://www.cbat.eps.harvard.edu/cbet/000800/CBET000824.txt. Retrieved 5 July 2011. 
  5. ↑ 5.0 5.1 Johnston, Robert (21 September 2014). "(2478) Tokai". http://www.johnstonsarchive.net/astro/astmoons/am-02478.html. 
  6. ↑ 6.0 6.1 6.2 Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R. et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal 791 (2): 11. doi:10.1088/0004-637X/791/2/121. Bibcode: 2014ApJ...791..121M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014ApJ...791..121M. Retrieved 18 June 2017. 
  7. ↑ 7.0 7.1 7.2 7.3 Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T. et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal 814 (2): 13. doi:10.1088/0004-637X/814/2/117. Bibcode: 2015ApJ...814..117N. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015ApJ...814..117N. Retrieved 19 June 2017. 
  8. ↑ 8.0 8.1 8.2 8.3 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. doi:10.1093/pasj/63.5.1117. Bibcode: 2011PASJ...63.1117U.  (online, AcuA catalog p. 153)
  9. ↑ 9.0 9.1 9.2 9.3 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. doi:10.1088/0004-637X/741/2/90. Bibcode: 2011ApJ...741...90M. 
  10. ↑ 10.0 10.1 10.2 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. doi:10.1016/j.icarus.2012.07.026. Bibcode: 2012Icar..221..365P. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012Icar..221..365P. Retrieved 19 June 2017. 
  11. ↑ Higgins, D.; Pravec, P.; Kusnirak, P.; Warner, B.; Galad, A.; Oey, J. et al. (January 2007). "(2478) Tokai". Central Bureau Electronic Telegrams 824 (824): 1. Bibcode: 2007CBET..824....1H. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2007CBET..824....1H. Retrieved 19 June 2017. 
  12. ↑ Oey, Julian (January 2016). "Lightcurve Analysis of Asteroids from Blue Mountains Observatory in 2014". The Minor Planet Bulletin 43 (1): 45–51. ISSN 1052-8091. Bibcode: 2016MPBu...43...45O. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2016MPBu...43...45O. Retrieved 19 June 2017. 
  13. ↑ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus 261: 34–47. doi:10.1016/j.icarus.2015.08.007. Bibcode: 2015Icar..261...34V. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V. Retrieved 19 June 2017. 
  14. ↑ "2478 Tokai (1981 JC)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=2478. Retrieved 18 June 2017. 
  15. ↑ "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html. Retrieved 18 June 2017. 



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