|Discovered by||Catalina Sky Survey (703)|
|Discovery date||6 October 2013|
|Near-Earth object, Apollo asteroid, Venus-crossing asteroid, Mars-crossing asteroid|
|Epoch 5 October 2013 (JD 2456570.5)|
|Uncertainty parameter 8|
(last seen 2013)
|Aphelion||2.5730 AU (384.92 Gm)|
|Perihelion||0.74447 AU (111.371 Gm)|
|1.6587 AU (248.14 Gm)|
|2.14 yr (780.31 d)|
|0° 27m 40.86s / day|
|Earth MOID||1.70448×10−5 AU (2.54987×103 km)|
|Venus MOID||0.03407 AU|
|Jupiter MOID||2.66285 AU (398.357 Gm)|
|Dimensions||21-52 meters (69–171 ft)|
2013 TX68 is an Apollo asteroid and near-Earth object discovered on October 6, 2013 by the Catalina Sky Survey, during which it was near a close approach of 5.4 Lunar distances (LD) from the Earth.[a] The asteroid only has a 10-day observation arc which makes long-term predictions of its position less certain. It was observed for three days as it approached Earth in the night sky starting with the sixth of October, 2013. Then it became unobservable by being between the Earth and the Sun, then not recovered due to its small size and dimness. Precovery images by Pan-STARRS from 29 September 2013 were announced on 11 February 2016 that extended the observation arc to 10 days. It was removed from the Sentry Risk Table on 11 February 2016, so there is no risk of impact from this object for the next hundred years or more. The asteroid was last observed on October 9, 2013.
The asteroid has a poorly constrained orbit, has not been observed since 2013, and often makes approaches to Earth. One such approach occurred sometime between March 6–10, 2016, with an uncertainty in the time of closest approach of ±2 days. While the nominal (best-fit) orbit suggested that it would pass 0.03 AU (4,500,000 km; 2,800,000 mi) from the Earth on March 8, it was calculated to pass as close as 0.0002 AU (30,000 km; 19,000 mi) (0.07 LD) or as far away as 0.1 AU (15,000,000 km; 9,300,000 mi). There was no risk of an Earth impact in 2016. JPL's graphic representation of 2013 TX68's orbit showed it was approaching Earth from the sunward side for an approach near the eighth of March with a chance of being detected by telescopes as it flew by. It was not expected to be more than 100 degrees from the Sun until March 9 and was expected to have an apparent magnitude of roughly 20.3. The asteroid was not recovered during the 2016 approach. During the March 2016 passage the uncertainty region for the asteroid covered as much as a 45 degree region of the sky.
2013 TX68 was listed on the Sentry Risk Table. The asteroid is 21–52 meters (69–171 ft) across, making it approximately twice as large as the Chelyabinsk meteor. However, it is not listed as a potentially hazardous asteroid because it is less than 100 meters (330 ft) in diameter. With an insignificant 1-day observation arc, it was listed on the Sentry Risk Table with a 1 in 20 million chance it could impact Earth on March 5, 2016, but that threat was quickly ruled out. With a short 3-day observation arc, it was listed on the Sentry Risk Table with a 1 in 300 million chance it could impact Earth on September 28, 2017. The nominal (best-fit) solution shows that 2013 TX68 should be around 1.5AU from Earth on 28 September 2017. It was removed from the Sentry Risk Table on 11 February 2016 when precovery images gave it a 10-day observation arc.
If it were ever to impact Earth, it would likely create a large fireball in the sky and possibly an impact crater 100–575 meters (328–1,886 ft) across, assuming an impact angle of less than 45 degrees.
- The time of closest approach for the 2013 pass is known with an accuracy of better than 1 minute.
- "MPEC 2013-T64 : 2013 TX68". IAU Minor Planet Center. 2013-10-07. Retrieved 2016-02-12. (K13T68X)
- "JPL Small-Body Database Browser: (2013 TX68)" (last observation: 2013-10-09; arc: 10 days). Jet Propulsion Laboratory. Retrieved 4 April 2016.
- "2013 TX68 Impact Risk (3 day arc)". Wayback Machine: Jet Propulsion Laboratory. Archived from the original on April 3, 2014. Retrieved 1 January 2016.
- Small Asteroid to Pass Close to Earth March 8
- "MPEC 2016-C131: DAILY ORBIT UPDATE (2016 FEB. 11 UT)". IAU Minor Planet Center. 2016-02-11. Retrieved 2016-02-12.
- "Date/Time Removed". NASA/JPL Near-Earth Object Program Office. Retrieved 2016-02-12.
- "2013TX68 Ephemerides for 1–20 March 2016". NEODyS (Near Earth Objects – Dynamic Site). Archived from the original on 18 March 2016. Retrieved 2016-03-08.
- Don Yeomans (2016-03-17). "Asteroid 2013 TX68 and Slooh". Asteroid Day. Retrieved 2016-03-21.
- "2013 TX68 Impact Risk (1 day arc)". Wayback Machine: Jet Propulsion Laboratory. 2013-10-09. Archived from the original on October 9, 2013. Retrieved 2016-02-13.
- "2013TX68 Ephemerides for 28 September 2017". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 2016-02-06.
- 2013 TX68 at the JPL Small-Body Database