2020 XR

2020 XR is an Apollo near-Earth object and potentially hazardous asteroid roughly 390 m in diameter. With a 5-day observation arc it was briefly listed as having a 1 in 11,000 chance of impacting Earth on 1 December 2028 placing it at the top of the Sentry Risk Table with a Palermo scale rating of -0.70.

Discovery
2020 XR was discovered by Pan-STARRS 2 on 4 December 2020, when it was 0.426 AU from Earth and had a solar elongation of 75°. It came to perihelion on 8 December 2020. On 2 January 2021, it passed 0.328 AU from Earth.

On 13 December 2020, precovery observations from 2013, 2016, and mid-2020 extended the observation arc from 8 days to 7.8 years allowing the asteroid to be removed from the Sentry Risk Table.

2024
It was the Earth perturbations of the asteroid in 2024 that determined if an impact was possible in December 2028. On 4 December 2024, the asteroid will pass 0.0147 AU from Earth with an uncertainty region of about ±800 km. This will increase the asteroid's orbital period by 10 days.

2028
On 7 November 2028, the asteroid will pass 0.121 AU from Earth. By 1 December 2028 the asteroid will be 0.19 AU from Earth with an uncertainty region of about ±10,000 km.