NEAR-EARTH ASTEROID: A relatively large asteroid, just discovered on August 28th, will fly past the Earth-Moon system on Sept 14th only 2.8 million km (7.4 lunar distances) away. 2012 QG42 is about as wide as three football fields and comes to us from just beyond the orbit of Mars. Astronomers who are now monitoring the space rock say it shines about as brightly as a 15th magnitude star. [3D orbit] [ephemeris] http://www.spaceweather.com/
M.P.E.C. 2012-Q72, issued on 2012 Aug. 28, reports the discovery of the PHA asteroid 2012 QG42 (discovery magnitude 16.8) by Catalina Sky Survey on images taken on August 26 with a 0.68-m Schmidt + CCD.
2012 QG42 has an estimated size of 200 m – 500 m (H=20.4) and it will have a close approach with Earth at about 7.43 LD (Lunar Distances) or 0.019 AU at 0510 UT on 14 Sept. 2012. This asteroid will reach an average magnitude of 13.6 around September 10-12. 2012 QG42 is a current radar target for ground based radio telescopes. Astronomers at Goldstone and Arecibo will try to observe it on September as “this object should be a really strong delay-Doppler imaging target“.
It was classified as a PHA ((Potentially Hazardous Asteroid). PHA are asteroids larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.