|Minor planet category||Apollo|
|Dimensions||~4 to 10 metre|
2012 KT42 is an asteroid discovered by Alex R. Gibbs of the Mt. Lemmon Survey (part of the Catalina Sky Survey) with a 1.5-m reflector + CCD on May 28, 2012. The asteroid had a close approach to the Earth on May 29, 2012, approaching to only ~8950 miles / ~14,440 km above the planet's surface. This means 2012 KT42 came inside the Clarke Belt of geosynchronous satellites. As of May 28, 2012, the estimated 5 to 10 meter wide asteroid ranked #6 on the top 20 list of closest-approaches to Earth. There was no danger of a collision during the close approach. 2012 KT42 would pass roughly 0.01 AU (1,500,000 km; 930,000 mi) from Venus on 2012 July 8.
It is estimated that an impact would produce an upper atmosphere air burst equivalent to 11 kt TNT, roughly equal to Hiroshima's Little Boy. The asteroid would be vaporized as these small impacts occur approximately once per year. A comparable-sized object caused the Sutter's Mill meteorite in California on 2012 April 22. It was removed from the Sentry Risk Table on 2012 May 30.
- "Conversion of Absolute Magnitude to Diameter". Minor Planet Center. Retrieved 2012-05-30.
- "2012 KT42 Orbit". Minor Planet Center. 2012-05-29. Retrieved 2012-05-30.
- "JPL Close-Approach Data: (2012 KT42)". 2012-05-29 last obs (arc=1 day; Uncertainty=5). Retrieved 2012-05-29.
- "Earth Impact Risk Summary: 2012 KT42". NASA/JPL Near-Earth Object Program Office. Retrieved 2012-05-29.
- "Date/Time Removed". NASA/JPL Near-Earth Object Program Office. Retrieved 2012-05-30.
- JPL Small-Body Database Browser for 2012 KT42
- 2012 KT42 - Close Approach (Remanzacco Observatory in Italy)
- Images from Flyby (spaceweather.com)
- MPEC 2012-K66 : 2012 KT42 (Minor Planet Center Discovery announcement)
- Planetary Defense Blog post on 2012 KT42
- Video: Tiny Asteroid 2012 KT42 Crossing The Sky (universetoday May 29, 2012)
- The Peculiar Flyby of Asteroid 2012 KT42 (Pasquale Tricarico : May 29, 2012)