The existing Maunakeya Astronomical Observatories returned to service this weekend and it did not take long to achieve a significant result not only for science but also for ensuring Earth's safety.
The observations of the 2006 QV89 terrestrial asteroid, made on August 11 with the Canada-France-Hawaii Telescope (CFHT), have ruled out a possible future threat of impact from the Earth by this asteroid for the next century.
2006 QV89 was discovered on August 29, 2006 by a telescope in Arizona, and observations are only possible until September 8, 2006, when the asteroid is not observed by Earth telescopes. The orbit determined by these limited observations had considerable uncertainty, and it was impossible to rule out the low likelihood of the asteroid hitting the Earth in the future, possibly as early as 2019. Last month, observations with the very large telescope at the European Southern Observatory (VLT) in Chile did not find the asteroid where it would appear if it were on a trajectory that would affect Earth this September. That ruled out impact in 2019, but impact for 2020 remains an option, along with nearly two dozen more in the next hundred years, eight of which over the next decade.
"There is a big difference between knowing where there is no dangerous asteroid and knowing where it is," says David Tolen, an astronomer at the Institute of Astronomy at the University of Hawaii, who has led the effort to restore QV89 since 2006.
This summer provided the first clear opportunity to recover the asteroid after it was discovered, but the uncertainty about its position in the sky reached approximately 30 degrees (60 times the diameter of the moon) in mid-July, becoming even larger as it approached of the asteroid to Earth, "This made the use of a large wide-field telescope absolutely necessary," Tolen noted. Only part of this area of uncertainty was portrayed by CFHT on July 14, but operations on existing telescopes were terminated on July 16 because of the protest against Maunakea.
"We found at least a dozen asteroids in the July 14 data, which are close to the region where QV89 could have been from 2006, but stopping operations prevented us from confirming which, if any, of these sites was QV89 for 2006 "said Tolen,
With access to blocked telescopes in Maunakeia, Tolen joined the assistance of Marco Michelli from the NEO Coordination Center of the European Space Agency in Frascati, Italy. Michelle is a graduate of UH, leading the effort to rule out the 2019 impact scenario with ESO's VLT. He pointed a telescope in Spain to the site of the best of the applicant sites, but after two hours of data collection, the object of the predicted position could not be conclusively different from the electronic noise in the data. It was a great relief to learn that CFHT will resume operations last weekend.
"Our highest goal for Saturday night was the top QV89 contender in 2006, and despite some thin clouds and a lot of moonlight, it only took us four minutes to get proof that we had found the right object," said Tolen.
The International Astronomical Union's Small Planet Center announced the worldwide recovery on Sunday, and impact monitoring services at the Jet Propulsion Laboratory and the University of Pisa / SpaceDys in Italy immediately began reducing numbers to update impact estimates. A little over an hour later, David Farnokia of the Center for Earth Object Research at NASA's Jet Propulsion Laboratory in Pasadena announced that all impact scenarios for the next century had been eliminated.
"This result is just one example of Maunakey's telescopes protecting the Earth observing and studying asteroids entering the Earth's surroundings," said Kelly Feist, Head of Earth Proximity Monitoring Program at the Planetary Defense Coordination Office of NASA, which supported the observations.
In the same way that meteorologists use meteorological satellite imagery to track hurricanes to determine if they pose a threat to humans and property, astronomers use telescopes to track asteroids near Earth to determine if they pose a shock hazard. "A different asteroid, the 2019 NX5, broke away from us while Maunakea's telescopes were closed, which is unfortunate," Tolen said. "We are relieved that we were able to catch the 2006 QV89 before our window closed. We are even more relieved that this will not affect the Earth."