(706765) 2010 TK7

Near-Earth asteroid and Earth trojan January 2022 yes (706765) 2010 TK 7 #FFC2E0 PIA14405-full crop.jpg Asteroid 2010 TK 7 (circled in green) in image from the WISE spacecraft padding: 4px; line-height: 1.4em; 1 October 2010 WISE spacecraft LEO, polar orbit (706765) 2010 TK 7 Earth trojan Aten (2014) Apollo (2013)WayBack Machine 2013 Epoch@MPC 13 January 2016 (JD 2457400.5) 0 768 days (2.10 yr) 0.99972 AU Gm on 0.80918 AU Gm on 1.1903 AU Gm on on 0.19059 1.00 yr (365.10 d) 20.890° 96.498° 45.927° 354.14° 29.8 km/sspeed v = 42.1219 1/0.9989 − 0.5/0.9989. 379 123 m 0.059 0.049 20.8 (when near Earth) to 23.6 20.8 0.98602 ms / day 0.0837911 AU Gm on (706765) 2010 TK 7 is a sub-kilometer near-Earth asteroid and the first Earth trojan discovered; it precedes Earth in its orbit around the Sun. Trojan objects are most easily conceived as orbiting at a Lagrangian point, a dynamically stable location (where the combined gravitational force acts through the Sun's and Earth's barycenter) 60 degrees ahead of or behind a massive orbiting body, in a type of 1:1 orbital resonance. In reality, they oscillate around such a point. Such objects had previously been observed in the orbits of Mars, Jupiter, Neptune, and the Saturnian moons Tethys and Dione. 2010 TK 7 has a diameter of about 300 m -2 us. Its path oscillates about the Sun–Earth Lagrangian point (60 degrees ahead of Earth), shuttling between its closest approach to Earth and its closest approach to the point (180 degrees from Earth). The asteroid was discovered in October 2010 by the NEOWISE team of astronomers using NASA's Wide-field Infrared Survey Explorer (WISE). Discovery WISE, a space telescope launched into Earth orbit in December 2009, imaged 2010 TK 7 in October 2010 while carrying out a program to scan the entire sky from January 2010 to February 2011. Spotting an asteroid sharing Earth's orbit is normally difficult from the ground, because their potential locations are generally in the daytime sky. After follow-up work at the University of Hawaii and the Canada–France–Hawaii Telescope, its orbit was evaluated on 21 May 2011 and the trojan character of its motion was published in July 2011. The orbital information was published in the journal Nature by Paul Wiegert of the University of Western Ontario, Martin Connors of Athabasca University and Christian Veillet, the executive director of the Canada–France–Hawaii Telescope. Physical and orbital characteristics left|thumb|2010 TK 7's spiraling path (green) relative to Earth and its orbit (blue dots) over the course of half a tadpole loop; each spiral turn represents a year's motion 2010 TK 7 has an absolute magnitude of luminosity (determinable because of its known location) of about 20.8. Based on an assumed albedo of 0.1, its estimated diameter is about 300 meters. No spectral data are yet available to shed light on its composition. 2010 TK 7 would exert a surface gravitational force of less than 1 20,000 that of Earth. At the time of discovery, the asteroid orbited the Sun with a period of 365.389 days, close to Earth's 365.256 days. As long as it remains in 1:1 resonance with Earth, its average period over long time intervals will exactly equal that of Earth. On its eccentric (e = 0.191) orbit, 2010 TK 7's distance from the Sun varies annually from 0.81 AU to 1.19 AU. It orbits in a plane inclined about 21 degrees to the plane of the ecliptic. Trojans do not orbit right at Lagrangian points but oscillate in tadpole-shaped loops around them (as viewed in a corotating reference frame in which the planet and Lagrangian points are stationary); 2010 TK 7 traverses its loop over a period of 395 years.lower-alpha Because of its orbital inclination and eccentricity, 2010 TK 7's position relative to Earth is actually a complicated, tightly coiled spiral; however, if its average position relative to Earth over a year is represented by a single point, that point will follow the tadpole loop. 2010 TK 7's loop is so elongated that it sometimes travels nearly to the opposite side of the Sun with respect to Earth. Its movements do not bring it any closer to Earth than 20 million kilometers (12.4 million miles), which is more than 50 times the distance to the Moon. 2010 TK 7 was at the near-Earth end of its tadpole in 2010–2011, which facilitated its discovery. 2010 TK 7's orbit has a chaotic character, making long-range predictions difficult. Prior to 500 AD, it may have been oscillating about the yes Lagrangian point (60 degrees behind Earth), before jumping to yes via yes. Short-term unstable libration about yes, and transitions to horseshoe orbits are also possible. Newer calculations based on an improved orbit determination confirm these results. center horizontal 300 Animation of 2010 TK 7 orbit from 1600 to 2500 Animation of 2010 TK7.gif Relative to Sun and Earth Animation of 2010 TK7 around Earth.gif Around Earth (with Sun) Animation of 2010 TK7 around Sun.gif Around Sun (with Earth) Yellow Sun RoyalBlue EarthMagenta 2010 TK 7 Accessibility from Earth left|thumb|Position of 2010 TK 7 relative to Earth in 2011 thumb|Effective potential plot showing Earth's Lagrangian points (not to scale); contours around yes and yes represent tadpole loop paths Because Earth trojans share Earth's orbit and have little gravity of their own, less energy might be needed to reach them than the Moon, even though they are much more distant. However, 2010 TK 7 is not an energetically attractive target for a space mission because of its orbital inclination: It moves so far above and below Earth's orbit that the required change in velocity for a spacecraft to match its trajectory coming from Earth's would be 9.4 km/s, whereas some other near-Earth asteroids require less than 4 km/s. During the 5 December 2012 Earth close approach of 0.197 AU km mi on on, the asteroid had an apparent magnitude of about 21. See also 614689 2020 XL 5, the second Earth trojan discovered Claimed moons of Earth Provisional designation in astronomy, the naming convention used for astronomical objects immediately following their discovery Notes 1 References 2 2012-11-07 last obs JPL Small-Body Database Browser: 2010 TK7 http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3548081 31 March 2016 2010 TK7 Orbit Minor Planet Center http://www.minorplanetcenter.net/db_search/show_object?object_id=2010+TK7 1 September 2015 Choi Charles Q. First Asteroid Companion of Earth Discovered at Last http://www.space.com/12443-earth-asteroid-companion-discovered-2010-tk7.html 27 July 2011 Space.com 2011-07-27 Connors Martin Wiegert Paul Veillet Christian Earth's Trojan asteroid 27 July 2011 Nature 475 7357 481–483 10.1038/nature10233 2011Natur.475..481C 21796207 205225571 http://www.nasa.gov/mission_pages/WISE/news/wise20110727.html NASA's WISE Mission Finds First Trojan Asteroid Sharing Earth's Orbit 27 July 2011 NASA 1 September 2015 2 May 2017 https://web.archive.org/web/20170502055548/https://www.nasa.gov/mission_pages/WISE/news/wise20110727.html dead Keys Sonia MPEC 2010-T45 : 2010 TK7 IAU Minor Planet Center 2010-10-07 http://www.minorplanetcenter.net/mpec/K10/K10T45.html 2011-07-31 http://www.astro.uwo.ca/~wiegert/2010TK7/ Earth's first Trojan asteroid: 2010 TK7 Astro.uwo.ca 27 July 2011 1 September 2015 http://www.nbcnews.com/id/43914196 https://web.archive.org/web/20200924000821/http://www.nbcnews.com/id/43914196 dead 24 September 2020 Found at last: First Earth companion asteroid NBC News 27 July 2011 28 July 2011 2011-08-03 last obs (arc=40 days; Uncertainty=2) JPL Close-Approach Data: (2010 TK7) http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2010TK7;cad=1#cad 2012-01-21 AstDyS 2010TK7 Ephemerides for 2012 Department of Mathematics, University of Pisa, Italy https://newton.spacedys.com/astdys/index.php?pc=1.1.3.1&n=2010TK7&oc=500&y0=2012&m0=11&d0=01&h0=0&mi0=0&y1=2013&m1=1&d1=1&h1=0&mi1=0&ti=1.0&tiu=days 2012-01-21 Carlos de la Fuente Marcos Raúl de la Fuente Marcos 18 February 2021 Transient Terrestrial Trojans: Comparative Short-term Dynamical Evolution of 2010 TK7 and 2020 XL5 Research Notes of the American Astronomical Society 5 2 29 2021RNAAS...5...29D 10.3847/2515-5172/abe6ad free https://www.bbc.co.uk/news/science-environment-14307987 Trojan asteroid seen in Earth's orbit by Wise telescope BBC News 2011-07-28 2011-07-29 Jonathan Amos External links MPC Database entry for 2010 TK 7 NASA animation of its motion Alternate NASA animation of 2010 TK 7 motion https://web.archive.org/web/20130302070109/http://www.nasa.gov/mission_pages/WISE/news/wise20110727vid.html 2 March 2013 2010+TK7 2010TK7 706765 (706765) 2010 TK 7 Astronomy Stars Spaceflight Outer space Solar System Category:Aten asteroids Category:Earth co-orbital asteroids Category:Earth trojans Category:Discoveries by WISE 20101001