The Zwicky Transient Facility, known as ZTF, was installed on the Samuel Oschin Telescope at the California Institute of Technology's Palomar Observatory in March. Since then, it has observed over a thousand supernovae outside our galaxy, extreme cosmic events and more than a billion Milky Way stars.
[...] ZTF is also pretty good at spotting near-Earth asteroids that zoom past our planet. [...] But this asteroid, known as 2019 AQ3, isn't like anything they've seen before. Quanzhi Ye, a postdoctoral scholar at the California Institute of Technology's data and science center for astronomy, spotted the images of the asteroid on January 4.
"This is one of the largest asteroids with an orbit entirely within the orbit of Earth -- a very rare species," Ye said.
Ye reported it to the International Astronomical Union's Minor Planet Center, which officially categorizes asteroids and other objects in our solar system. His data, along with that of other telescopes around the world, helped determine the orbit that 2019 AQ3 takes around the sun.
The asteroid is one of the first to be found that remains within Venus' orbit. It has a vertically angled orbit that takes it in a loop up and over the space where the planets orbit the sun. It has the shortest year of any known asteroid, completing its orbit every 165 days. It's also estimated to be fairly large, about a mile across. But researchers don't know the true size just yet, due to the limited data.
2019 AQ3 [wikipedia.org] has a diameter estimated at 1.4 km, a perihelion of 0.4036 AU, and an aphelion of 0.7737 AU.
Mercury orbits the Sun between 0.3075 AU and 0.4667 AU, and Venus orbits the Sun between 0.7184 AU and 0.7282 AU.