Astronomers have spotted three near-Earth asteroids (NEAs) hiding in the glare of the Sun. One of these asteroids is the largest “potentially hazardous” object spotted in the last three years, according to NOIRLab.
Asteroids hiding in the Sun’s glare
The asteroids were discovered using twilight observations made with the Dark Energy Camera at the Cerro Tololo Inter-Americal Observatory in Chile, which was fabricated by the US Department of Energy. These newly-discovered NEAs are part of a population of asteroids that lurks between the orbits of Earth and Venus. It is particularly challenging to make observations in this region between both planets because of the glare of the Sun.
“Only about 25 asteroids with orbits completely within Earth’s orbit have been discovered to date because of the difficulty of observing near the glare of the Sun,” said aid Scott S. Sheppard, lead author of the study published in The Astronomical Journal, in a press statement. Sheppard is an astronomer at the Earth and Planets Laboratory of the Carnegie Institution of Science.
The astronomers got around this challenge by taking brief observations when there were favourable conditions at twilight. The astronomers only got two brief 10-minute windows to do this. Also, such observations are very near to the horizon, meaning that they had to peer through a thick layer of Earth’s atmosphere, which can blur and distort the objects.
The discovered asteroids
“So far we have found two large near-Earth asteroids that are about 1 kilometre across, a size that we call planet killers,” added Sheppard, speaking of two of the three discovered asteroids.
Amongst the trio, one 1.5-kilometre-wide asteroid called 2022 AP7 has an orbit that may someday put it on a collision course with our planet. The other, LJ4 and 2021 PH27, have orbits that are safely constrained inside the limits of Earth’s orbit. Interestingly, 2021 PH7 is the closest known asteroid to the Sun. Due to this, its surface gets hot enough to melt lead.