Researchers from NASA have just announced that newly taken observations show that it is unlikely that asteroid 2011 AG5 will strike the the Earth in 2040. It had previously been thought the asteroid had at least a 0.2% chance of hitting the Earth in 2040. There are still some uncertainties about the exact orbit that the 140-meter diameter near-Earth asteroid follows.
So to learn more about the asteroid, University of Hawaii researchers, “Dave Tholen, Richard Wainscoat and Marco Micheli used the Gemini 8-meter telescope at Mauna Kea, Hawaii to successfully recover and observe the small and very faint asteroid on October 20, 21 and 27, 2012. In addition to improving our knowledge of the orbit, the Gemini observations also suggest the asteroid varies in brightness as it rotates and therefore may be elongated. Gemini is managed by the Association of Universities for Research in Astronomy (AURA). In addition to the Gemini measurements, Tholen, Micheli and Garrett Elliott obtained less conclusive observations on October 9 & 10 with the University of Hawaii 2.2-meter telescope, also situated on the summit of Mauna Kea. After extensive astrometric analysis by the team in Hawaii, all observations were then sent to the International Astronomical Union’s Minor Planet Center in Cambridge, Massachusetts.”
“An analysis of the new data conducted by NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California, shows that the risk of collision in 2040 has been eliminated. The updated trajectory of 2011 AG5 is not significantly different, but the new observations have reduced the orbit uncertainties by more than a factor of 60, meaning that the Earth’s position in February 2040 no longer falls within the range of possible future paths for the asteroid. With the updated orbit, the asteroid will pass no closer than 890,000 km (over twice the distance to the moon) in Feb. 2040, the epoch of the prior potential collision.”
“Earlier in 2012, NASA’s NEO Program Office conducted a contingency deflection analysis for the 2040 potential impact of 2011 AG5. Among the findings was that any new observations either in 2012, or in 2013 when the object will be much easier to observe, had a 95% likelihood of eliminating the hazard posed by 2011 AG5. If the potential for impact had been confirmed, the impact odds could have risen as high as 1 in 10, but the study released in May 2012 found that scenario to be unlikely. While the interest in 2011 AG5 has been reduced by the new results, the experience gained by studying this potential real-world deflection problem has demonstrated that NASA is well situated to predict the trajectories of Earth threatening asteroids.”
Here is some more info on the asteroid:
“2011 AG5 (also written 2011 AG5) is a near-Earth asteroid and potentially hazardous object. It has a diameter of about 140 meters. It was removed from the Sentry Risk Table on 21 December 2012 and as such it now has a rating of 0 on the Torino Scale.”
“Pan-STARRS precovery images from 8 November 2010 extended the observation arc to 317 days. Observations by the Gemini 8.2-meter telescope at Mauna Kea recovered the asteroid on October 20, 21 and 27, 2012, and extended the observation arc to 719 days. The October 2012 observations have reduced the orbit uncertainties by more than a factor of 60, meaning that the Earth’s position in February 2040 no longer falls within the range of possible future paths for the asteroid. Until 21 December 2012 it was listed on the Sentry Risk Table with a rating on the Torino Scale of Level 1. A Torino rating of 1 is a routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger. It was discovered on 8 January 2011 by the Mt. Lemmon Survey at an apparent magnitude of 19.6 using a 1.52-metre reflecting telescope. The asteroid is noted by the Minor Planet Center for a potential close approach to the Earth in the year 2040 of about 0.001756 AU (163,200 mi). It is estimated that an impact would produce the equivalent of 100 megatons of TNT, roughly twice that of the most powerful nuclear weapon ever detonated (Tsar Bomba). This is powerful enough to damage a region at least a hundred miles wide.”
Image Credits: Asteroid via Wikimedia Commons