Caltech diagram shows the orbit of the asteroid 2020 AV2.

The first asteroid orbiting the sun between the planets Mercury and Venus has been spotted by astronomers at Palomar Observatory in north San Diego County.

Researchers used Caltech’s Zwicky Transient Facility, a special camera attached to the observatory’s 48-inch Samuel Oschin Telescope, to track the  tiny body, which is about a mile in diameter.

The finding was reported in scientific publications earlier this month.

“An encounter with a planet probably flung the asteroid into Venus’s orbit,” said Caltech Physics Professor Tom Prince. “It’s the opposite of what happens when a space mission swings by a planet for a gravity boost. Instead of gaining energy from a planet, it loses it.”

The asteroid, designated 2020 AV2, belongs to a small class of asteroids known as Atiras, which are bodies with orbits that fall within the orbit of Earth. More specifically, it is the first “Vatira” asteroid, with the “V” standing for Venus. Vatira asteroids, which were only hypothesized until now, have orbits that fall entirely inside the orbit of Venus.

The Zwicky camera is particularly adept at finding asteroids because it scans the entire sky rapidly and thus can catch the asteroids during their short-lived appearances in the night sky. Because Vatiras orbit so close to our sun, they are only visible at dusk or dawn.

Show comments

Chris Jennewein

Chris Jennewein is Editor & Publisher of Times of San Diego.