Using a variety of ground-based telescopes, astronomers have discovered three new near-Earth asteroids orbiting the Sun but inside Earth’s orbit, with one of these asteroids having the possibility of one day in the future impacting the Earth.
An international team using the Dark Energy Camera (DECam) mounted on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile, a Program of NSF’s NOIRLab, has discovered three new near-Earth asteroids (NEAs) hiding in the inner Solar System, the region interior to the orbits of Earth and Venus. This is a notoriously challenging region for observations because asteroid hunters have to contend with the glare of the Sun.
By taking advantage of the brief yet favorable observing conditions during twilight, however, the astronomers found an elusive trio of NEAs. One is a 1.5-kilometer-wide asteroid called 2022 AP7, which has an orbit that may someday place it in Earth’s path. The other asteroids, called 2021 LJ4 and 2021 PH27, have orbits that safely remain completely interior to Earth’s orbit. Also of special interest to astronomers and astrophysicists, 2021 PH27 is the closest known asteroid to the Sun. As such, it has the largest general-relativity effects of any object in our Solar System and during its orbit its surface gets hot enough to melt lead.
You can read their paper here [pdf].
2002 AP7 is the largest such potentially dangerous asteroid discovered in eight years. Its present orbit however never brings it closer to the Earth than 4.4 million miles, and it will be many thousands of years before that orbit might result in an impact. This of course doesn’t prevent foolish mainstream news outlets like the New York Times to label it a “planet-killer.”
The importance of this study however is that it underlines the possibility that there might be other such asteroids lurking close to the Sun that are difficult to spot. This is a blind spot in our asteroid surveys that needs to be eliminated.
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