Detected a potentially dangerous ‘planet killer’ for Earth

Nov. 1 () –

Twilight observations with the Dark Energy Camera (DECam) on the Victor M. Blanco Telescope of the Cerro Tololo Observatory in Chile have allowed the detection of three near-Earth asteroids hidden in the glare of the sun, one of which is the largest potentially dangerous object for the Earth discovered in the last eight years.

These NEA are part of an elusive population that lurks within the orbits of Earth and Venus. One is a 1.5-kilometer-wide asteroid called 2022 AP7, which has an orbit that could one day put it in Earth’s path. The other asteroids, called 2021 LJ4 and 2021 PH27, have orbits that remain safely entirely inside the 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 heats up enough to melt lead.

KILLERS OF PLANETS

“Our twilight survey is scouring the area within the orbits of Earth and Venus for asteroids,” he said. it’s a statement Scott S. Sheppard, an astronomer at the Carnegie Institution for Science’s Earth and Planets Laboratory and lead author of the paper describing this work. “So far we have found two large near-Earth asteroids that are about 1 kilometer in diameter, orn size we call planet killers.”

“There are probably only a few NEAs with similar sizes left to find, and these large undiscovered asteroids probably have orbits that keep them inside the orbits of Earth and Venus most of the time.”Sheppard said. “To date, only about 25 asteroids with orbits entirely within Earth’s orbit have been discovered due to the difficulty of observing close to the sun’s glare.”

Finding asteroids in the inner solar system is a daunting observing challenge. Astronomers have only two short 10-minute windows each night to survey this area and have to contend with a bright background sky as a result of glare from the sun. Furthermore, such observations are very close to the horizon, which means that astronomers they have to observe through a thick layer of Earth’s atmosphere, which can blur and distort their observations.

Discovering these three new asteroids despite these challenges was made possible by DECam’s unique observing capabilities. The state-of-the-art instrument is one of the world’s highest performing wide-field CCD imagers, giving astronomers the ability to capture large areas of the sky with great sensitivity.

Astronomers refer to observations as “deep” if they capture faint objects. When searching for asteroids within Earth’s orbit, the ability to capture deep and wide field observations is indispensable.

“Large areas of sky are required because inner asteroids are rare, and deep imaging is needed because asteroids are faint and you’re fighting against the bright twilight sky near the sun, as well as the distorting effect of Earth’s atmosphere,” Sheppard said. . “DECam can cover large areas of the sky at depths that smaller telescopes can’t reach, allowing us to go deeper, cover more sky, and probe the inner solar system in a way never before seen.”

In addition to detecting asteroids that could pose a threat to Earth, this research is an important step in understanding the distribution of small bodies in our solar system. Asteroids that are farther from the sun than Earth are easier to detect. So these more distant asteroids tend to dominate current theoretical models of the asteroid population.

Detecting these objects also allows astronomers to understand how asteroids are transported throughout the inner solar system and how gravitational interactions and heat from the sun can contribute to their fragmentation.

“Our DECam survey is one of the largest and most sensitive searches ever conducted for objects within Earth orbit and near the orbit of Venus,” said Sheppard. “This is a unique opportunity to understand what kinds of objects lurk in the inner solar system.”

The findings are published in The Astronomical Journal.