1685 Toro

1685 Toro
Discovery [1]
Discovered by C. A. Wirtanen
Discovery site Lick Observatory
Discovery date 17 July 1948
Designations
MPC designation 1685 Toro
Named after
 Betulia Toro Herrick
(wife of astronomer
Samuel Herrick)[2]
1948 OA
Apollo, NEO
Mars-crosser
Orbital characteristics [1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc 67.76 yr (24750 days)
Aphelion 1.9634 AU (293.72 Gm)
Perihelion 0.77133 AU (115.389 Gm)
1.3674 AU (204.56 Gm)
Eccentricity 0.43590
1.60 yr (584.02 d)
24.190°
0° 36m 59.112s / day
Inclination 9.3806°
274.30°
127.11°
Earth MOID 0.0505905 AU (7.56823 Gm)
Jupiter MOID 3.48145 AU (520.818 Gm)
Jupiter Tisserand parameter 4.716
Physical characteristics
Dimensions 3 km[3]
3.4 km
4.1 km[4]
3.810±0.049 km[5]
4.1 km (derived)[6]
Mean radius
 1.7 km
10.1995 h (0.42498 d)[1][7]
10.196 h[8]
10.19540 h[9]
10.195 h[10]
10.1862±0.0006 h[11]
10.199±0.003 h[12]
10.203±0.003 h[13]
10.185±0.003 h[14]
0.31[1]
0.29[4]
0.38±0.33[15]
0.247±0.049[5]
B–V = 0.880
U–B = 0.470
S (Tholen)
S (SMASS)
S [6]
14.23

    1685 Toro, provisional designation 1948 OA, is an eccentric asteroid classified as near-Earth object, about 4 kilometers in diameter. It is also an Apollo asteroid, a subgroup of near-Earth asteroids that cross the orbit of Earth. It was discovered by American astronomer Carl A. Wirtanen at Lick Observatory on Mount Hamilton, California on 17 July 1948.[3][16]

    The asteroid orbits the Sun at a distance of 0.8–2.0 AU once every 1.60 years (584 days). Its orbit shows a very high eccentricity of 0.44 and is tilted by 9 degrees to the plane of the ecliptic. The stony S-type asteroid is reported to be composed of L chondrite[17] with a high geometric albedo in the range of 0.24–0.34. It has an extremely well-measured rotation period of 10.2 hours.[7][8][9][10][11][12][13][14]

    Its orbit also shows a 5:8 resonance with Earth[18] and in a near 5:13 resonance with Venus. It was the third Apollo asteroid to be discovered. The current resonance with Earth will last for only a few thousand years. Calculations show that Toro will leave it in 2960 AD, and that it will enter the region of 5:13 resonance with Venus in 3470. This is because the distance from Earth's orbit will become larger and that from Venus's orbit smaller. A study of long-term stability shows that the alternating resonances will possibly be broken roughly 3 million years from now because of close approaches between Toro and Mars.[19]

    Based on orbital paths, Toro is the best candidate for the source of the Sylacauga meteorite, the first meteorite authenticated to have struck a human, Mrs. Ann Hodges of Sylacauga, Alabama on 30 November 1954.[20] Toro's Earth minimum orbit intersection distance of 0.0509 AU (7,610,000 km; 4,730,000 mi),[1] is just above the 0.05-AU requirement to be listed as a potentially hazardous asteroid. With an orbital uncertainty of 0, its orbit and future close approaches are well determined.[1]

    The minor planet was named after the maiden name of Betulia Herrick, wife of American astronomer Samuel Herrick. Herrick had studied the asteroid's orbit, and requested the name, along with the other asteroid, 1580 Betulia.[21][22]

    References

    1. 1 2 3 4 5 6 "JPL Small-Body Database Browser: 1685 Toro (1948 OA)" (2015-11-07 last obs.). Jet Propulsion Laboratory. Retrieved 22 April 2016.
    2. ↑ Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names – (1685) Toro. Springer Berlin Heidelberg. p. 134. ISBN 978-3-540-29925-7. Retrieved November 2015.
    3. 1 2 Waldemar Kaempffert (26 December 1948). "Science in Review: Research Work in Astronomy and Cancer Lead Year's List of Scientific Developments". The New York Times. p. 87. ISSN 0362-4331. Retrieved 4 August 2011.
    4. 1 2 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 November 2015.
    5. 1 2 Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; 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. Retrieved November 2015.
    6. 1 2 "LCDB Data for (1685) Toro". Asteroid Lightcurve Database (LCDB). Retrieved November 2015.
    7. 1 2 Higgins, David (March 2008). "Asteroid Lightcurve Analysis at Hunters Hill Observatory and Collaborating Stations: April 2007 - June 2007". The Minor Planet Bulletin 35 (1): 30–32. Bibcode:2008MPBu...35...30H. ISSN 1052-8091. Retrieved November 2015.
    8. 1 2 Dunlap, J. L.; Gehrels, T.; Howes, M. L. (August 1973). "Minor planets and related objects. IX. Photometry and polarimetry of (1685) Toro". Astronomical Journal 78: 491. Bibcode:1973AJ.....78..491D. doi:10.1086/111447. Retrieved November 2015.
    9. 1 2 De Angelis, G. (May 1995). "Asteroid spin, pole and shape determinations". Planetary and Space Science 43 (5): 649–682. Bibcode:1995P&SS...43..649D. doi:10.1016/0032-0633(94)00151-G. Retrieved November 2015.
    10. 1 2 Torppa, J.; Aksnes, K.; Dai, Z.; Grav, T.; Hahn, G.; et al. (August 2005). "Spins and Shapes of Potentially Hazardous Asteroids". American Astronomical Society 37. Bibcode:2005DPS....37.1526T. Retrieved November 2015.
    11. 1 2 Higgins, David; Pravec, Petr; Kusnirak, Peter; Hornoch, Kamil; Brinsfield, James W.; et al. (September 2008). "Asteroid Lightcurve Analysis at Hunters Hill Observatory and Collaborating Stations: November 2007 - March 2008". The Minor Planet Bulletin 35 (3): 123–126. Bibcode:2008MPBu...35..123H. ISSN 1052-8091. Retrieved November 2015.
    12. 1 2 Higgins, David (January 2011). "Period Determination of Asteroid Targets Observed at Hunters Hill Observatory: May 2009 - September 2010". The Minor Planet Bulletin 38 (1): 41–46. Bibcode:2011MPBu...38...41H. ISSN 1052-8091. Retrieved November 2015.
    13. 1 2 Oey, Julian (October 2011). "Lightcurve Analysis of Asteroids from Leura and Kingsgrove Observatory for the Second Half of 2009 and 2010". The Minor Planet Bulletin 38 (4): 221–223. Bibcode:2011MPBu...38..221O. ISSN 1052-8091. Retrieved November 2015.
    14. 1 2 Warner, Brian D. (January 2013). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2012 June - September". The Minor Planet Bulletin 40 (1): 26–29. Bibcode:2013MPBu...40...26W. ISSN 1052-8091. Retrieved November 2015.
    15. ↑ Thomas, C. A.; Trilling, D. E.; Emery, J. P.; Mueller, M.; Hora, J. L.; et al. (September 2011). "ExploreNEOs. V. Average Albedo by Taxonomic Complex in the Near-Earth Asteroid Population". The Astronomical Journal 142 (3): 12. Bibcode:2011AJ....142...85T. doi:10.1088/0004-6256/142/3/85. Retrieved November 2015.
    16. ↑ "1685 Toro (1948 OA)". Minor Planet Center. Retrieved November 2015.
    17. ↑ Hartmann, W. K. (2005). Moons & Planets (5th ed.). Belmont, Calif.: Brooks/Cole.
    18. ↑ Danielsson, L.; Ip, W.-H. (1972-05-26). "Capture Resonance of the Asteroid 1685 Toro by the Earth". Science 176 (4037): 906–907. Bibcode:1972Sci...176..906D. doi:10.1126/science.176.4037.906. Retrieved 2012-06-09.
    19. ↑ Williams, J. G. & Wertherill, G. W. Astronomical Journal, Vol. 78, p. 510 (1973). Minor planets and related objects. XIII. Long-term orbital evolution of (1685) Toro
    20. ↑ H. Povenmire. The Sylacauga, Alabama Meteorite: The Impact Locations, Atmosphere Trajectory, Strewn Field and Radiant. H.Povenmire. Abstracts of the Lunar and Planetary Science Conference, volume 26, page 1133, (1995)
    21. ↑ Schmadel, Lutz D. (2009). Dictionary of Minor Planet Names: Addendum to Fifth Edition: 2006–2008. Berlin: Springer Berlin. ISBN 978-3-642-01964-7. Retrieved 4 August 2011.
    22. ↑ University of California, Samuel Herrick, Engineering; Astronomy: Los Angeles

    External links

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