2012 TC4

Near-Earth micro-asteroid the titanium alloy Ti-6Al-4V February 2018 yes 2012 TC 4 #FFC2E0 2012 TC4 radar animation before closest approach.gif Radar movie of 2012 TC 4 Pan-STARRS 1 Haleakala Obs. 4 October 2012 2012 TC 4 NEO Apollo 1 October 2017 (JD 2458027.5) 1 5.19 yr (1,897 d) 1.8786 AU 0.9335 AU 1.4061 AU 0.3361 1.67 yr (609 d) 332.79° 0.5911 ms / day 0.8572° 198.23° 222.58° 0.000149 AU LD on on 3 0.03 AU 15 × 8 m 7 - 13 m15 m 0.2038 hlightcurve-plot 0.142 h NPAR 0.35 0.1 0.30 0.01 (radiometric) E/Xe S (assumed) V–R 0.41 0.02 12.9–31 26.7 26.8 2012 TC 4 is a tumbling micro-asteroid classified as a bright near-Earth object of the Apollo group, approximately 10 m ft off 1 us in diameter. It was first observed by Pan-STARRS at Haleakala Observatory on the Hawaiian island of Maui, in the United States. As of 1 October 2017, it had a small Earth minimum orbital intersection distance of 0.000149 AU km on on. On 12 October 2017, it passed Earth at 0.00033524 AU km on on. The asteroid was removed from the Sentry Risk Table on 16 October 2017 and with a 5-year observation arc has a well-known orbit. For example, on the previously risk-listed date of 12 October 2022, it is now known that the asteroid will be more than 3 AU e6km unit on from Earth. Approaches to large bodies Orbital modeling shows the asteroid nominally passed about 1 million km from Earth in October 1986, but the uncertainty region suggests it could have passed as close as 20 km. + Date (UT) Object distance in km(center–center) 3-Σuncertaintyin km Speed-relativein km/s 13 October 1996 Earth 753 000 ± 7000 6.445 13 October 1996 Moon 530 000 ± 6300 7.144 12 October 2012 Earth 94 965 ± 0.32 7.123 12 October 2012 Moon 113 886 ± 0.64 6.773 12 October 2017 05:42 Earth 50 151 ± 0.14 7.647 12 October 2017 19:19 Moon 277 697 ± 0.34 6.101 Data from JPL 60 solution date 3 November 2017 2012 Earth encounter left|thumb|2012 TC 4 appears as a dot of this composite of 37 individual 50-second exposures. 2012 TC 4 was discovered on 4 October 2012 at apparent i-band magnitude 20.1 while the asteroid was 0.03 AU km mi on off from Earth. It came within 0.000634 AU (0.247 LD, 94,800 km, 58,900 mi) from Earth on 12 October 2012. During the 2012 close approach, the asteroid only had an observation arc of 7 days, between 4 and 11 October 2012, so the exact distance of the 2017 closest approach was poorly constrained. With the 7 day observation arc, the asteroid had a 3-sigma chance of passing between 0.00008818 and 0.002896 AU (0.034 to 1.127 LD, 13,200–433,200 km, 8,200–269,200 mi) from Earth on 12 October 2017. Astronomers were certain that it would not pass closer than 6,800 km from the surface of Earth, ruling out any possibility that it could hit the Earth in 2017. 2017 Earth encounter vertical right 225 2012 TC4 orbit.png 2012 TC4 animation.gif 2012 TC4 from 2012 to 2017.gif Orbit in yellow among inner solar system planets before 2017 flyby Orbit of 2012 TC 4 deflected by Earth's gravity. Earth is blue. For reference, a geosynchronous satellite and the Moon are included in this animation. The green path of 2012 TC 4 turns darker as it dips below the ecliptic plane (click for animation). Orbits from pre-2012 to post-2017 encounters. The orbit of 2012 TC 4 has changed twice since 2012. On 12 October 2017 at 5:42 UT, the asteroid passed 0.00033524 AU km mi on off from Earth. Observations between July and October reduced the uncertainty region from several hundred thousand kilometers to about ±140 meters. The asteroid was removed from the Sentry Risk Table on 16 October 2017 using JPL solution #56. Prior to the encounter, it was rated −4.11 on the Palermo scale, with a 1 in 1,000 chance of impact over the next hundred years. Paul Chodas of NASA's Center for near-Earth Object Studies, and Vishnu Reddy of the University of Arizona's Lunar and Planetary Laboratory, viewed the 2017 flyby (inside of the orbit of the Moon) as a way to test and refine the global asteroid detection and tracking network designed to give warning of objects heading toward Earth. Reddy coordinated the effort, involving over a dozen institutions worldwide. In addition to the observation campaign, NASA used this exercise to test communications between the many observers and also to test internal U.S. government messaging and communications up through the executive branch and across government agencies, as it would during an actual predicted impact emergency. Results of the campaign were published on 3 November 2017. The asteroid remained too faint to be recovered with automated astronomical surveys until early September, but a more targeted observation with the Very Large Telescope recovered it on 27 July 2017 at apparent magnitude 26.8, while the asteroid was 0.4 AU km mi on off from Earth, making it one of the dimmest asteroid recoveries ever. As such, 2012 TC 4 has become the first known asteroid ever to be observed passing less than 1 Lunar distance from Earth twice in a row. At the time of recovery the asteroid was about 100 million times fainter than what can be seen with the naked eyeMath: and 500 times fainter than when it was discovered in 2012. As a result of the 2017 recovery observations, it was known that on 12 October 2017 at 5:42 UT, the asteroid would pass 0.0003352 AU km mi on off from Earth. Then at 19:19 UT, the asteroid would pass 0.001856 AU km mi on off from the Moon. 2012 TC 4 peaked at about apparent magnitude 12.9, and was too faint to be seen without a telescope. The Earth approach of 2017 increased the asteroid's orbital period from 1.67 years to 2.06 years. 2012 TC 4 reached a maximum apparent magnitude of 12.9 just prior to its closest approach, soon after which it came too close to the Sun to be seen with telescopes. It was last observed on 14 December 2017 at an apparent magnitude of 25. Physical properties 500pxSize reference of 2012 TC 4, based on radar observations. Fast rotator and tumbler Studies of the asteroid's light curve in October 2012, found it to have a rotation period of 0.2038 hours (or 12 minutes and 14 seconds) with a brightness variation of 0.93 magnitude (U=3-), which is indicative for a non-spherical shape.lightcurve-plot 2012 TC 4 is a fast rotator, which is rather typical for its small size. The fastest rotator currently known is 2014 RC, a similarly sized NEO, with a period of only 16 seconds. Lightcurves obtained during the 2017 encounter confirmed that 2012 TC 4 is in a non-principal axis rotation, commonly known as tumbling. The spin axis varies on timescales of minutes, with a second period of 0.142 hours (or 8.5 minutes). The lightcurve amplitude suggests a ratio of largest to smallest axis of at least 2.3. Radar observations Radar images were taken from Goldstone Observatory and Green Bank Telescope on 12 October 2017. The delay-doppler images had a range resolution of 1.9 meters/pixel, the highest resolution ever obtained using Goldstone transmissions. The images showed that 2012 TC 4 was a very elongated object about 50 feet (15 meters) long and roughly 25 feet (8 meters) wide. The high circular polarization ratio found for 2012 TC 4 is consistent with results seen from E- and V-type NEAs previously. Observations from Arecibo Observatory were planned, but had to be cancelled due to damage to the observatory as a result of Hurricane Maria. Composition The spectrum of 2012 TC 4 is that of an E- or Xe-type asteroid. E-type asteroids tend to have a high albedo (>0.30). This agrees with the albedo of 0.35 found for 2012 TC 4. This type of asteroids is commonly found in the inner Main Belt. 2012 TC 4 is composed of igneous material. The short rotation period of 2012 TC 4 implies that it is not a rubble pile but rather a monolithic object of non-negligible strength, which is typical for very small asteroids. Orbit change As a result of 2012 TC 4's frequent approaches to Earth, its orbit changes significantly over short periods of only decades. Its two observed close approaches and their effects are shown below: Date Event Semimajor axis (AU) Perihelion (AU) Aphelion (AU) Eccentricity Inclination (°) Argument of perihelion (°) Ascending node (°)2012-10-01 pre-2012 approach 1.2744 0.9015 1.6472 0.2926 1.4097 234.7282 198.55602012-10-12 2012 approach 1.3837 0.9115 1.8559 0.3413 1.2320 228.5354 198.46222012-10-30 post-2012 approach 1.3893 0.9305 1.8480 0.3302 0.8582 223.1271 198.10332017-10-01 pre-2017 approach 1.4155 0.9410 1.8901 0.3353 0.8566 221.8553 198.00542017-10-12 2017 approach 1.7076 0.9522 2.4630 0.4424 0.1693 218.4570 193.65202017-10-30 post-2017 approach 1.6492 0.9711 2.3273 0.4112 0.5327 248.6359 208.50512050-01-01 pre-2050 approach 1.6226 0.9688 2.2765 0.4030 0.5266 266.6192 197.8009 Between 2012 and 2017, 2012 TC 4's average distance from the Sun increased by almost 0.4 AU, with the time it takes to orbit the sun increasing by 250 days. Its closest approach to the Sun also increased significantly, from 90% of the Earth's distance to the Sun to 97%, and its inclination lowered slightly, going from 1.4 degrees to less than 0.5 degrees relative to Earth's orbit. As a result of non-gravitational forces such as the Yarkovsky effect on small bodies, it is difficult to constrain its orbit more than a few decades into the past or future. See also List of asteroid close approaches to Earth List of asteroid close approaches to Earth in 2012 List of asteroid close approaches to Earth in 2017 NASA Planetary Defense Coordination Office Notes lightcurve-plot Lightcurve plot of at the Palmer Divide Observatory by Brian D. Warner (2012). Rotation period 0.2038 0.0002 hours with a brightness amplitude of 0.93 0.05 mag. Summary figures for 2012 TC 4 at the LCDB References 2017-12-14 last obs. JPL Small-Body Database Browser: (2012 TC4) https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2012TC4&view=OPC https://web.archive.org/web/20201128213549/http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2012TC4;cad=1 2020-11-28 live Jet Propulsion Laboratory 2017-10-17 2012 TC4 Minor Planet Center https://minorplanetcenter.net/db_search/show_object?utf8=%E2%9C%93&object_id=2012+TC4 2017-11-04 2012 TC4 2017-09-28 A Very Close Encounter http://www.eso.org/public/announcements/ann17052/ www.eso.org 2017-08-11 MPEC 2012-T18 : 2012 TC4 IAU Minor Planet Center 2012-10-07 http://www.minorplanetcenter.net/mpec/K12/K12T18.html 2017-03-14 (K12T04C) MPEC 2017-P26 : 2012 TC4 IAU Minor Planet Center 2017-08-06 http://www.minorplanetcenter.net/mpec/K17/K17P26.html 2017-08-06 (K12T04C) Archive: Close Approach table for 2012 TC4 (using 7 day obs arc) http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2012TC4;cad=1 https://archive.today/20130403030915/http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2012TC4;cad=1 dead 3 April 2013 JPL NASA 2014-10-22 NEODyS-2 2012TC4 Department of Mathematics, University of Pisa, Italy https://newton.spacedys.com/neodys/index.php?pc=1.1.0&n=2012+TC4 2017-11-04 2012TC4 Ephemerides for 12 October 2017 NEODyS (Near Earth Objects Dynamic Site) https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=2012TC4&oc=500&y0=2017&m0=10&d0=11&h0=0&mi0=0&y1=2017&m1=10&d1=13&h1=0&mi1=0&ti=1.0&tiu=hours 2017-08-07 NEODyS-2 Possible recovery list Department of Mathematics, University of Pisa, Italy https://newton.spacedys.com/neodys/index.php?pc=4.1&ots=r https://archive.today/20170314142012/http://newton.dm.unipi.it/neodys/index.php?pc=4.1&ots=r dead 2017-03-14 2017-03-14 Archive: Earth Impact Risk Summary: 2012 TC4 (7 day observation arc) NASA/JPL Near-Earth Object Program Office https://cneos.jpl.nasa.gov/sentry/details.html#?des=2012%20TC4 https://web.archive.org/web/20121124024319/http://neo.jpl.nasa.gov/risk/2012tc4.html 2012-11-24 dead 2017-03-13 Horizons Batch for 2022-10-12 JPL Horizons https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272012+TC4%27&START_TIME=%272022-10-12%27&STOP_TIME=%272022-10-13%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27 2022-10-04 Asteroid Flyby Will Benefit NASA Detection and Tracking Network 28 July 2017 JPL NASA https://www.jpl.nasa.gov/news/news.php?feature=6906 8 March 2018 TC4: HOW NASA PLANS TO TEST ITS PLANETARY DEFENSE SYSTEMS ON CLOSE-APPROACH ASTEROID Newsweek 6 October 2017 http://www.newsweek.com/asteroid-tc4-nasa-planetary-defense-exercise-paul-chodas-679660 2017-10-07 Orbit of NEA 2012 TC4 http://2012tc4.astro.umd.edu/2012TC4_orbit.shtml University of Maryland 2017-10-11 Date/Time Removed NASA/JPL Near-Earth Object Program Office https://cneos.jpl.nasa.gov/sentry/removed.html https://archive.today/20171017181102/https://cneos.jpl.nasa.gov/sentry/removed.html 17 October 2017 live 2017-10-17 The 2012 TC4 Observing Campaign University of Maryland http://2012tc4.astro.umd.edu/ 2017-11-02 NEA 2012 TC4 -- Physical Properties University of Maryland http://2012tc4.astro.umd.edu/2012TC4_properties.shtml 2017-11-02 The 2012 TC4 Observing Campaign – Radar observations UPDATE October 12, 2017 University of Maryland http://2012tc4.astro.umd.edu/References/TC4RadarUpdate.txt 2017-11-02 The 2012 TC4 Observing Campaign -- Radar animations University of Maryland http://2012tc4.astro.umd.edu/References/radar_movies.shtml 2017-11-02 https://web.archive.org/web/20171107004512/http://2012tc4.astro.umd.edu/References/radar_movies.shtml 7 November 2017 dead Physical Characterization of NEA 2012 TC4 Ryan William H. Ryan Eileen V. University of Maryland 2017 PDF http://2012tc4.astro.umd.edu/References/ryan_pdc2017.pdf 8 March 2018 Coleman Nancy NASA's planetary defense system will be put to the test in October 1 August 2017 CNN http://www.cnn.com/2017/08/01/us/nasa-asteroid-flyby-planetary-defense-trnd/index.html 2 August 2017 Goldstone Radar Observations Planning: 2012 TC4 JPL https://echo.jpl.nasa.gov/asteroids/2012TC4/tc4_planning.2017.html 2017-11-02 Astronomers Complete First International Asteroid Tracking Exercise JPL https://www.jpl.nasa.gov/news/news.php?release=2017-289 3 November 2017 2017-11-03 S. Fornasier B. E. Clark E. Dotto July 2011 Spectroscopic survey of X-type asteroids Icarus 214 1 131–146 2011Icar..214..131F 10.1016/j.icarus.2011.04.022 1105.3380 118549118 External links Interesting Asteroids Past Earth Close encounters — Sormano Astronomical Observatory Image and animation of 2012 TC4 Virtual Telescope Project Asteroid 2012 TC4 On Track For Close Earth Flyby AstroBob 10/3/17 Asteroid 2012 TC4: House-Sized Asteroid Almost Hits Earth (PHOTO, VIDEO) 13 October 2012 2012 TC4 orbit and observations, Minor Planet Center 2012TC4 2012TC4 # Category:Minor planet object articles (unnumbered) # # # 20121012 20171012 20121004