Ye says he hopes the Twilight program will lead to more Atira discoveries, and he looks forward to the possible selection by NASA of the Near-Earth Object Camera (NEOCam) mission, a proposed spacecraft created to look for asteroids closer to the sun than previous surveys. "Like other asteroids, Atiras are leftovers from the formation of our solar system". Since the mission is created to use infrared to track the heat signatures of asteroids, it will be able to successfully find other Atira objects.
Upon its closest approach to the sun, the asteroid, dubbed 2019 LF6, moves inside Mercury's orbit.
"You don't find kilometre-size asteroids very often these days", Quanzhi Ye, a postdoctoral scholar at the California Institute of Technology who was on the team that helped discover 2019 LF6, explained on Monday.
"Thirty years in the past, individuals began organizing methodical asteroid searches, discovering bigger objects first, however now that nearly all of them have been discovered, the larger ones are uncommon birds", Tom Price of Caltech describes.
"Both of the large Atira asteroids that were found by ZTF orbit well outside the plane of the Solar System", said Caltech Professor Tom Prince, a member of the ZTF team. The unique orbit of the asteroid is what allowed it to remain undiscovered for so long. The new mission aims to find near-earth objects so scientists can understand how asteroids were formed and how they will evolve over time as the Solar System changes. Because ZTF scans the sky so rapidly, it is well-suited for finding Atira asteroids, which have short observing windows. Both of the objects orbit basically perpendicular to the essentially flat plane of the solar system that the planets inhabit. Because they're so close to the sun, the best time to find them is around 20 to 30 minutes before sunrise or after sunset.
Most asteroids are found deeper in space, particularly beyond Mars in the main asteroid belt, but there could be many more hidden objects lurking between our planet and the sun.