4179 Toutatis
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Discovery
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| Discovered by | Christian Pollas |
| Discovery date | January 4, 1989 |
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Designations
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| Named after | Toutatis |
| Alternate name(s) | 1934 CT; 1989 AC |
| Minor planet category |
Apollo, Alinda, Mars-crosser |
| Epoch October 22, 2004 (JD 2453300.5) | |
| Aphelion | 4.128 AU (616.914 Gm) |
| Perihelion | 0.934 AU (137.739 Gm) |
| Semi-major axis | 2.531 AU (377.326 Gm) |
| Eccentricity | 0.630 |
| Orbital period | 4.03 a (1471.15 d) |
| Average orbital speed | 16.69 km/s |
| Mean anomaly | 219.29° |
| Inclination | 0.445° |
| Longitude of ascending node | 124.45° |
| Argument of perihelion | 279.65° |
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Physical characteristics
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| Dimensions | 4.5×2.4×1.9 km |
| Mass | 5.0×1013 kg |
| Mean density | 2.1 g/cm³ |
| Equatorial surface gravity | 0.0010 m/s² |
| Escape velocity | 0.0019 km/s |
| Rotation period | 5.41 to 7.33 d[1] |
| Albedo | 0.13[1] |
| Temperature | ~174 K |
| Spectral type | S |
| Apparent magnitude | 8.8 (when near Earth)[2] to 22.4[3] |
| Absolute magnitude (H) | 15.30[1] |
4179 Toutatis/1989 AC (
/tuːˈtɑːtɨs/ too-tah-tis) is an Apollo, Alinda, and Mars-crosser asteroid with a chaotic orbit produced by a 3:1 resonance with the planet Jupiter, a 1:4 resonance with the planet Earth, and frequent close approaches to the terrestrial planets.[4] Due to its very low orbital inclination (0.47°) and its orbital period of very nearly 4 years, Toutatis makes frequent close approaches to Earth, with a currently minimum possible distance (Earth MOID) of just 0.006 AU (2.3 times as far as the Moon).[1] The approach on September 29, 2004, was particularly close, at 0.0104 AU[5] (within 4 lunar distances) from Earth, presenting a good opportunity for observation, with Toutatis shining at magnitude 8.8 when brightest.[2] The most recent close approach of 0.0502 AU (7,510,000 km; 4,670,000 mi) happened on November 9, 2008.[6][5] The next close approach will be December 12, 2012, at a distance of 0.046 AU (6,900,000 km; 4,300,000 mi),[5][6] and at magnitude 10.7.[7] By the middle of May 2012 the asteroid will become brighter than magnitude 19.5.[8]
Its rotation combines two separate periodic motions into a non-periodic result; to someone on the surface of Toutatis, the Sun would seem to rise and set in apparently random locations and at random times at the asteroid's horizon.
It was first sighted on February 10, 1934, as object 1934 CT, and then promptly lost. It remained a lost asteroid for several decades until it was recovered on January 4, 1989, by Christian Pollas, and was named after the Celtic god Toutatis/Teutates, known to popular culture as the God the cartoon character Astérix's chief Vitalstatistix evokes so that the sky may never fall on his head.
Radar imagery has shown that Toutatis is a highly irregular body consisting of two distinct "lobes", with maximum widths of about 4.6 km and 2.4 km respectively. It is hypothesized that Toutatis formed from two originally separate bodies which coalesced at some point, with the resultant asteroid being compared to a "rubble pile".
The low inclination of the orbit allows frequent transits, where the inner planets Mercury, Venus, Earth, and Mars can appear to cross the Sun. Earth did this in January 2009, and will also do it in 2012, 2016, and 2020.[9]
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[edit] Dual resonances and chaotic behavior
Toutatis has a 3:1 orbital resonance with Jupiter and a near-1:4 resonance with Earth.[4][10] The frequent close approaches to the terrestrial planets lead to chaotic behaviour in the orbit of Toutatis,[11] making precise long-term predictions of its location progressively inaccurate over time.[11] Estimates in 1993 put the Lyapunov time horizon for predictability at around 50 years,[11] after which the uncertainty region becomes larger with each close approach to a planet. Without the perturbations from the terrestrial planets the Lyapunov time would be close to 10,000 years.[11]
[edit] Collision risk
Given that Toutatis makes many close approaches the Earth, such as in 1992, 1996, 2000, 2004, 2008, and 2012, it is listed as a potentially hazardous object.[6] The likelihood of collision in the distant future is considered to be very small.[12] As a planet-crossing asteroid, Toutatis is likely to be ejected from the Solar System on a time scale of a few tens of thousands of years, giving it a limited number of opportunities to strike Earth before disappearing forever. As with many Near-Earth objects, the fear mongering doomsday crowd spread misinformation about Toutatis back in 2004.[13]
[edit] See also
[edit] References
- ^ a b c d e "JPL Small-Body Database Browser: 4179 Toutatis (1989 AC)". http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1989AC. Retrieved 2008-02-05.
- ^ a b "AstDys (4179) Toutatis Ephemerides for 2004". Department of Mathematics, University of Pisa, Italy. http://hamilton.dm.unipi.it/astdys/index.php?pc=1.1.3.1&n=4179&oc=500&y0=2004&m0=9&d0=28&h0=0&mi0=0&y1=2004&m1=9&d1=30&h1=0&mi1=0&ti=1&tiu=hours. Retrieved 2010-06-27.
- ^ "AstDys (4179) Toutatis Ephemerides 2059". Department of Mathematics, University of Pisa, Italy. http://hamilton.dm.unipi.it/astdys/index.php?pc=1.1.3.1&n=4179&oc=500&y0=2059&m0=8&d0=31&h0=0&mi0=0&y1=2059&m1=9&d1=14&h1=0&mi1=0&ti=1.0&tiu=days. Retrieved 2010-06-27.
- ^ a b "Trick or Treat: It's Toutatis!". Science@Nasa. 2000-10-31. http://science.nasa.gov/headlines/y2000/ast31oct_1.htm. Retrieved 2009-01-27.
- ^ a b c "NEODys (4179) Toutatis Close Approaches". Department of Mathematics, University of Pisa, Italy. http://newton.dm.unipi.it/neodys/index.php?pc=1.1.8&n=Toutatis. Retrieved 2009-03-20.
- ^ a b c "JPL Close-Approach Data: 4179 Toutatis (1989 AC)". 2011-05-22 last obs (arc=77.28 years). http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Toutatis;cad=1#cad. Retrieved 2011-11-13.
- ^ "NEODys (4179) Toutatis Ephemerides for December 2012". Department of Mathematics, University of Pisa, Italy. http://hamilton.dm.unipi.it/astdys/index.php?pc=1.1.3.1&n=4179&oc=500&y0=2012&m0=12&d0=12&h0=0&mi0=0&y1=2012&m1=12&d1=19&h1=0&mi1=0&ti=3&tiu=hours. Retrieved 2010-06-27.
- ^ "(4179) Toutatis Ephemerides for May 2012". NEODyS (Near Earth Objects - Dynamic Site). http://newton.dm.unipi.it/neodys/index.php?pc=1.1.3.1&n=4179&oc=500&y0=2012&m0=05&d0=01&h0=0&mi0=0&y1=2012&m1=06&d1=01&h1=0&mi1=0&ti=1.0&tiu=days. Retrieved 2011-11-13.
- ^ "Solex by Aldo Vitagliano". Archived from the original on 2009-04-29. http://chemistry.unina.it/~alvitagl/solex/. Retrieved 2009-03-03.
- ^ "Toutatis is in a 3:1 mean-motion resonance with Jupiter (rotating frame)". Gravity Simulator. http://www.orbitsimulator.com/gravity/articles/toutatis.html. Retrieved 2009-01-27.
- ^ a b c d Whipple, L.; Shelus, Peter J. (1993). "Long-Term Dynamical Evolution of the Minor Planet (4179) Toutatis". Icarus 105 (2): 408–419. doi:10.1006/icar.1993.1137.
- ^ "Close call for earth ahead? – possible collision with asteroid Toutatis". USA Today (Society for the Advancement of Education). 1993. http://findarticles.com/p/articles/mi_m1272/is_n2577_v121/ai_13953460/.
- ^ David Morrison (September 27, 2004). "Close Flyby This Week from Asteroid Toutatis". Asteroid and Comet Impact Hazards (NASA). http://impact.arc.nasa.gov/news_detail.cfm?ID=151. Retrieved 2011-11-13.
[edit] External links
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Wikimedia Commons has media related to: 4179 Toutatis |
- Toutatis radar information
- Toutatis Home Page, by one of the asteroid's discoverers (private access only)
- Space.com: Video of Toutatis's close approach to Earth, 29 Sept, 2004
- Interesting views of asteroid
- Astrobiology Magazine article
- Simulating the orbit of Toutatis exposes its resonance with Jupiter
- Orbital simulation from JPL (Java) / Ephemeris
- Toutatis Hi-res Video
- Six-Centimeter Radar Observations of 4179 Toutatis
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