2012 KT42

2012 KT₄₂ is an Apollo near-Earth asteroid first observed by astronomer Alex R. Gibbs of the Mount Lemmon Survey with a 1.5-meter reflecting telescope on 28 May 2012.

2012 KT₄₂

Designations
Minor planet category	Apollo NEO
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 5
Aphelion	2.4839 AU (371.59 Gm)
Perihelion	0.71144 AU (106.430 Gm)
Periastron	94.628°
Semi-major axis	1.5977 AU (239.01 Gm)
Eccentricity	0.55470
Orbital period (sidereal)	2.02 yr (737.60 d)
Mean anomaly	261.31°
Mean motion	0° 29m 17.052s / day
Inclination	2.1932°
Longitude of ascending node	69.515°
Argument of perihelion	259.13°
Earth MOID	0.000968708 AU (144,916.7 km)
Physical characteristics
Dimensions	~4–10 metres[2]
Synodic rotation period	0.06057 h (3.634 min)
Absolute magnitude (H)	29[3] 29.0[1]

Overview

The asteroid had a close approach to the Earth on 29 May 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. In May 2012, the estimated 5- to 10-metre-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 passed roughly 0.01 AU (1,500,000 km; 930,000 mi) from Venus on 8 July 2012.^[1]

It is estimated that an impact would produce an upper atmosphere air burst equivalent to 11 kt TNT,^[4] 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 2 April 2012. It was removed from the Sentry Risk Table on 30 May 2012.^[5]