European Space Agency's Gaia satellite, originally meant to chart the stars, is also capable of sensing the presence and positions of multitudes of asteroids in the sky.
In Gaia's second data release in 2018, astronomers not only mapped out nearly 1.7 billion of stars in the Milky Way galaxy, but also catalogued the positions and orbits of more than 14,000 asteroids in the solar system.
Among these thousands of space rocks are three new ones, the very first asteroid discoveries of ESA's Gaia mission.
A Stunning Asteroid Map
According to a news release from ESA, most of the asteroids spotted by Gaia have already been previously recorded.
Most of the asteroids are main-belt asteroids, which are found between the orbits of Mars and Jupiiter, or Trojan asteroids, which are found around the orbit of Jupiter. In the image shared by ESA, these are identified as the red- and orange-colored orbits.
Closer to the center, seen in the photo as yellow-colored orbits, are the near-Earth asteroids, which can come as close as 1.3 astronomical units to the sun.
The three orbits that are shown in the ESA photo as gray are the orbits of the asteroids that do not match other existing observations. These newly discovered objects were spotted by Gaia back in December 2018, then confirmed with follow-up observations using the Haute-Provence Observatory in France.
Unusually Tilted Orbit
Most asteroids orbit roughly on the same plane as the sun and the planets, but these three new asteroids are traveling on an orbit with a greater tilt than is often observed by astronomers. Measurements reveal that the new asteroids orbit at a tilted angle of 15 degrees or more compared to the orbital plane of many objects in the solar system.
Asteroids with heavily tilted orbits are more rarely observed than the asteroids with less tilted orbits, since many instruments are focused on the plane where most asteroids are. Since Gaia scans the entire sky for its purpose, it's possible for the satellite to discover more of these types of asteroids on a tilted orbit.
Online Alert System
Whenever Gaia detects an asteroid, the data is shared with an online alert system. It allows astronomers all around the world to conduct follow-up observations from the ground to confirm its presence and determine its orbit.
"So far, several tens of asteroids detected by Gaia have been observed from the ground in response to the alert system, all of them belonging to the main belt, but it is possible that also near-Earth asteroids will be spotted in the future," ESA revealed in the statement.
