Fast and efficient: this is what can qualify astronomers warning and reaction when David Rankin (Catalina Sky Survey, Arizona) picked up a small asteroid with the 1.5m telescope at the peak of Mount Lemmon. A few minutes after, warnings were sent to the astronomical community, allowing 7 observatories to catch the small asteroid in the three hours window before it entered the atmopshere above the Great Lake, on November 19th, 08h 26min UT. Things clearly evolved in the good way since the first asteroid discovered before Earth impact, in 2008!

2022 WJ1: 6th predicted Earth impactor

2008 TC3, 2014 AA, 2018 LA, 2019 MO and 2022 EB5. These asteroids have in common the fact that they are Earth impactors discovered before they actually entered the Earth atmopshere. Since November 19th, 2022, another one completed the list: 2022 WJ1! This small Apollo asteroid (Figure 1), estimated to be below 1-meter diameter, was discovered three hours before by David Rankin with the 1.5m telescope at the peak of Mount Lemmon (Catalina Sky Survey).

Figure 1- 2022 WJ1 orbit before it entered the Earth atmopshere. Credit: NASA/JPL
Figure 1- 2022 WJ1 orbit before it entered the Earth atmopshere. Credit: NASA/JPL

Bright fireball and potential meteorite fall

Formerly designated C8FF042, the small asteroid immediately attracted David Rankin attention, which allows him to send warning to the whole asteroidal community: thanks to this fast reaction, seven observatories were able to record the small object coming from the asteroid belt before it entered the atmosphere above Brantford (Ontario, Canada) on November 19th, 08h 26min UT.

The atmopsheric entry of the 2022 WJ1 asteroid triggered a very bright long lasting meteor that was recorded by many webcams and photographers (Figure 2). More than 50 people (Figure 3) reported their observation recorded under event 8984-2022. Dramatic videos were shot, espectially from the CN Tower cam in Toronto.

Figure 2- Dereck Bowen was trying to photography Leonids, when he accidentally captured the fireball associated to the 2022 WJ1 asteroid atmopsheric entry.Credit: Dereck Bowen
Figure 2- Dereck Bowen was trying to photography Leonids, when he accidentally captured the fireball associated to the 2022 WJ1 asteroid atmopsheric entry.Credit: Dereck Bowen
Figure 3- More than 50 witnesses reported their fireball observation associated to 2022 WJ1 atmopsheric entry. Credit: IMO/AMS
Figure 3- More than 50 witnesses reported their fireball observation associated to 2022 WJ1 atmopsheric entry (Event 8984-2022). Blue arrow is the trajectory automatically calculated from the fireball reports. Credit: IMO/AMS

According to NASA/ARES, meteorites could have landed on the ground, East of Grimsby (Canda), and larger fragments may have landed in Ontario Lake (Figure 4). Stay tuned for updated news!

Figure 4- Strenfield of potential fragments of 2022 WJ1 asteroid. The lighter meteorites (1 g) could have fallen in the yellow parts, and the larger (10 kg) fragments in the red part of the diagram. Credit: NASA/ARES
Figure 4- Strewnfield of potential fragments of 2022 WJ1 asteroid. The lighter meteorites (1 g) could have fallen in the yellow parts, and the larger (10 kg) fragments in the red part of the diagram. Credit: NASA/ARES

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