A small near-Earth asteroid designated 2023 BU made its closest approach on January 26, 2023 at 7:29 p.m. EST (4:29 p.m. PST, or January 27, 2023 at 00:29 UT) only 3,600 km (2,200 miles) over the southern tip of South America.

This is an artist’s impression of a rocky and water-rich asteroid being torn apart by the strong gravity of the white dwarf star GD 61. Image credit: Mark A. Garlick, Space-art.co.uk / University of Warwick / University of Cambridge.

2023 BU is a near-Earth asteroid with a diameter less than 8 m and an orbital period of 1.16 years.

It was discovered on January 21, 2023 by Gennadiy Borisov, an astronomer from Crimea, Ukraine, who discovered the first-known interstellar comet, 2I/Borisov, in 2019.

Additional observations were reported to the Minor Planet Center (MPC) and the data was then automatically posted to the near-Earth object confirmation page. After sufficient observations were collected, the MPC announced the discovery.

Within three days, a number of observatories around the world had made dozens of observations, helping astronomers better refine 2023 BU’s orbit.

NASA’s Scout impact hazard assessment system, which is maintained by the Center for Near Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory, analyzed the data from the MPC’s confirmation page and quickly predicted the near miss.

“Scout quickly ruled out 2023 BU as an impactor, but despite the very few observations, it was nonetheless able to predict that the asteroid would make an extraordinarily close approach with Earth,” said Dr. Davide Farnocchia, a navigation engineer at NASA’s Jet Propulsion Laboratory who developed Scout.

It is the fourth closest non-impacting approach known to Earth after 2020 VT4, 2020 QG, and 2021 UA1.

This orbital diagram from CNEOS’s close approach viewer shows 2023 BU’s trajectory — in red — during its close approach with Earth on January 26, 2023. Image credit: NASA / JPL-Caltech.

“While any asteroid in Earth’s proximity will experience a change in trajectory due to our planet’s gravity, 2023 BU will come so close that its path around the Sun is expected to be significantly altered,” the astronomers said.

“Before encountering Earth, the asteroid’s orbit around the Sun was roughly circular, approximating Earth’s orbit, taking 359 days to complete its orbit about the Sun.”

“After its encounter, the asteroid’s orbit will be more elongated, moving it out to about halfway between Earth’s and Mars’ orbits at its farthest point from the Sun.”

“The asteroid will then complete one orbit every 425 days.”

source: https://www.sci.news