Watch 2019 LF6 orbit the sun in this animation. The asteroid orbits completely within Earth’s orbit, circling the sun every 151 days, a record. The asteroid follows the white loop. Mercury’s orbit is pink, Venus purple and the Earth blue. NASA / JPL-Caltech
A newly discovered, kilometer-sized asteroid orbits the sun entirely inside Earth’s orbit. Named 2019 LF6 it takes just five months (151 days) to complete its orbit, the shortest known of any asteroid. 2019 LF6 belongs to the Atira asteroid family, a select group of 20 asteroids (to date) that all orbit interior to Earth’s orbit.
Always hidden in the glow of twilight due to its proximity to the sun, finding the asteroid was no easy task. Its discoverer, Quanzhi Ye, who works out of Caltech, used the Zwicky Transient Facility, or ZTF, a state-of-the-art camera at the Palomar Observatory that scans the skies every night for things that flicker or move. Astronomers call them transient objects; they include supernovae, flickering stars and asteroids on the move. ZTF scans the sky quickly, making it ideal for finding Atira asteroids, which because they appear so close to the sun, are only visible briefly during twilight.
Asteroid 2019 LF6 travels ...