Hawaii astronomers late last year discovered an asteroid that has a slim likelihood of striking the Earth in about seven years, and a telescope on Maunakea will be used to help track the object’s orbit.
In December, astronomers at the University of Hawaii’s Asteroid Terrestrial-impact Last Alert System, or ATLAS — a network of telescopes built on Haleakala, in Chile and South Africa — detected a previously unknown asteroid that passes close by the Earth every four years.
The next time the asteroid will approach the earth is in 2028, when it is expected to harmlessly pass our planet by. However, the asteroid’s next approach after that, in 2032, has an estimated 1.3% chance of striking Earth.
ATLAS principal investigator Larry Denneau described the asteroid — which is officially called 2024 YR4 — as one that “could take out a city” if it struck the planet. The asteroid ranges between 130 feet and 330 feet in length, but its material composition is still unknown.
The discovery of the asteroid and its relatively high threat level has triggered a response by the International Asteroid Warning Network, a worldwide collaboration of organizations and astronomers that gathers and shares information about potentially dangerous asteroids. Last week, the IAWN issued a notice about 2024 YR4 and has begun collecting data about the object.
“What people should know is that it’s still early,” said ATLAS principal investigator Larry Denneau. “It’s a low probability, but we’d like to bring it down to zero.”
Denneau said astronomers have been looking at data from other astronomical surveys to see if the object had been inadvertently detected previously, to no avail so far.
Denneau said 2024 YR4 has the dubious honor of being the first object potentially dangerous enough to trigger the IAWN protocols.
Consequently, other observatories will attempt to gather more information about the asteroid over the coming months and years in order to get a clearer picture of what it is made of, its orbit around the sun, its likelihood of intersecting with Earth’s orbit — and, if it does, the possible scale of the asteroid’s impact.
Depending on the asteroid’s composition, it could be dense enough to punch through the atmosphere and directly impact the ground, or it could explode mid-air while entering the atmosphere.
An asteroid about 160-200 feet wide — toward the bottom edge of 2024 YR4’s estimated size range — is believed to have detonated above a remote forest in Tunguska, Siberia, in 1908.
While the object left no impact crater, the explosion flattened about 830 square miles of
forest and shattered windows hundreds of miles away from the epicenter.
The Canada-France-Hawaii Telescope on Maunakea will conduct observations of 2024 YR4 later this month. UH Institute for Astronomy Director Doug Simons said that telescope will use a tool called the MegaCam to take a much closer look at the object and get a higher determination of its orbit than ATLAS could.
However, Simons said the astronomy community is still likely “months away” from a more definitive model of the asteroid’s orbit.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.
