Two years ago, on November 19, 2022, a Particularly bright meteorite appeared in the sky over the Canadian region of Niagara. And just hours earlier, researchers had determined that it would hit our planet. The data that came from this splendid “ball of fire” made it possible to characterize it, demonstrating that it came fromsmallest asteroid ever recordedcalled 2022 WJ1 (WJ1).
In an international study conducted by Western University and from Lowell Observatory (USA) scientists describe a pioneering and integrative approach to the study of near-Earth asteroids based largely on this extraordinary event.
Space observations
Astronomers, in particular, determined the composition and size of asteroid 2022 WJ1 (WJ1) before it fragmented upon entering Earth’s atmosphere, by comparing telescopic observations in Arizona with videos captured by cameras of the Southern Ontario Meteor Network.
The research is much more than a scientific curiosity: in fact, it not only reveals key details about WJ1, the smallest asteroid in space to have been characterized to date, but it defines the methodology for studying other space objects hitting Earththat is, combining telescope observation and camera footage to study the same space object.
The dimensions of WJ1 were determined with the Lowell Discovery Telescope (LDT) located in Arizona: telescope observations show that the surface of the celestial body was rich in silica, and that its diameter was between 40 and 60 cm, numbers that make it thesmallest asteroid ever recorded.
This is only the sixth asteroid discovered before the impact – explains Denis Vida, co-author of the work – Our new approach, discovering an asteroid through space observation and then subsequently observing it with ground-based cameras, has allowed us to confirm that our estimates correspond well to those obtained using a completely different approach
Using the Meteorological Camera Network Westernscientists captured the asteroid as it entered the atmosphere above Londonin Ontario, finishing near St. Catharinesin the same US state. And the subsequent measurements confirm the data obtained with the “traditional” approach.
This is only the second time an asteroid has been significantly characterized with telescopes before its impact on Earth – reports Teddy Kareta, who collaborated on the research – It is a testimony to our good fortune and preparation, but it is also due to the community that cares about protect the Earth from these celestial objects and is learning to work better together
The data obtained suggests that WJ1 falls into the category of chondrite astronomical objects Swhich silica-rich rocky bodies (hence the ‘S’ designation), are among the oldest bodies in the solar system and comprise the most common type of meteorite to strike Earth.
Probably, however, not all of WJ1’s fragments burned up in Earth’s atmosphere. Initial searches for meteorites and meteorite pieces never led to any no findings.
After two years, all the meteorites that have fallen to earth will have disappeared camouflaged with the landscape – explains Phil McCausland, another co-author – That said, there are people in the area who are looking and know what to look for. We may still get lucky and find a meteorite or two from this fall in the coming months and years
A particularly “lucky” study
Undoubtedly, the study was facilitated by aincredible combination of lucky factors: First of all, WJ1 was first discovered by Catalina Sky Survey in TucsonArizona, in November 2022, and shortly thereafter, astronomers predicted the object would hit Earth within three hours.
This gave scientists theenough time to telescopically observe the object while it was still in space and given astronomers time to gather the asteroid’s precise position and motion to refine its orbit.
All this allowed a more accurate determination of the point where the asteroid would have entered the Earth’s atmosphere, i.e. above the Great Lakes, on the border between the United States and Canada. And the predicted impact site also turned out to be particularly lucky, indeed in the middle of the network of meteor observation cameras from the Western in the same region.
The last but not the leastthe hours of warning of the asteroid impact allowed several members of the Western Meteor Physics Group and of theInstitute for Earth and Space Exploration from the Western to find clear weather to observe the incoming object.
And when the asteroid became too faint to be seen in our images, the telescope was moving at five degrees per second, fast enough to still track the object.
It was aincredible luck that this asteroid passed over the dark skies of Arizona at night before burning above theWestern’s excellent camera network. It’s hard to imagine better circumstances for doing this kind of research
he concludes Kareta
The work was published on The Planetary Science Journal.
Sources: Western University / The Planetary Science Journal
