# 2009 FD

Discovery[1] VLT image of the very faint near-Earth asteroid 2009 FD Kitt Peak (691) 16 March 2009 2009 FD Apollo NEO,[2] Epoch 2013-Nov-04 (Uncertainty=0)[2] 1.7361 AU (Q) 0.58960 AU (q) 1.1628 AU (a) 0.49296 1.25 yr 196.02° (M) 3.1361° 9.4968° 281.30° ~130 meters (430 ft)[3] 2.8×109 kg (assumed)[3] 4.0 h[2] 22.1[2]

2009 FD is an Apollo asteroid[2] (a class of near-Earth asteroid) with an orbit that places it at risk of a possible future collision with Earth. It has the 4th highest impact threat on the Palermo Technical Impact Hazard Scale.[4] It was discovered on 16 March 2009.[1] 2009 FD made a close pass to Earth on 27 March 2009 at a distance of 0.004172 AU (624,100 km; 387,800 mi)[5][6] and another on 24 October 2010 at 0.0702 AU.[5] 2009 FD was recovered at apparent magnitude 23[note 1] on 30 November 2013 by Cerro Paranal Observatory,[7] several months before the close approach of April 2014 when it will pass 0.1 AU from Earth.[5] It will brighten to roughly apparent magnitude 19.3 around mid-March 2014.[8]

NASA's Near Earth Program estimates its size to be 130 metres in diameter with a mass of around 2,800,000 tonnes.[3] NASA shows that 2009 FD will make two very close approaches in the late 22nd century, with the approach of 30 March 2190 currently having a 1 in 667 chance of impacting Earth.[3] The nominal 2190 Earth approach distance is 0.008 AU (1,200,000 km; 740,000 mi),[5] but orbit determination is complicated by the 2185 close approach.[5] The precise distance that it will pass from Earth and the Moon on 29 March 2185 will determine the 30 March 2190 distance. 2009 FD will pass closer to the Moon than Earth on 29 March 2185.[5] An impact in 2190 would cause severe devastation to a large region or tsunamis of significant size.[9] Due to 2009 FD's size, and its interactions with Mars and Venus, which increase its orbital uncertainty over time, it is rated −2.29 on the Palermo Scale, placing it relatively high on the Sentry Risk Table.[4]

## Past Earth-impact estimates

In January 2011, near-Earth asteroid 2009 FD (with observations through 7 December 2010) was listed on the JPL Sentry Risk Table with a 1 in 435 chance of impacting Earth on 29 March 2185.[10] In 2014 (with observations through 5 February 2014) the potential 2185 impact was ruled out.

## Notes

1. ^ At an apparent magnitude of 23, 2009 FD was roughly 4 million times fainter than can be seen with the naked eye.
Math: $(\sqrt[5]{100})^{23-6.5}\approx 3981071$