is a small (~2 meter) near-Earth object that passed about from the surface of Earth while passing over Antarctica on 25 October 2021 around 03:07 UT. Given the small size of the asteroid it only reached the brightness of Pluto at around apparent magnitude 14. Since it approached from the direction of the Sun, it was not discovered until 4 hours after closest approach.
The 2021 Earth approach lifted the orbit and increased the orbital period from 356 days to 413 days. This changed it from an Aten asteroid to an Apollo asteroid.
+Orbital Elements Parameter Epoch Period(p) Aphelion(Q) Perihelion(q) Semi-major axis(a) Eccentricity(e) Inclination(i) Units (days)AU(°) Pre-flyby 2021-Jul-01 355.6 1.351 0.614 0.982 0.3750 10.19° Post-flyby 2022-Jan-01 413.1 1.525 0.646 1.086 0.4046 0.006°
Notes
References
External links 2021 UA1 Close approach date: 2021 10 25.130000 (03 07 12.0) – MPC diagram using WebGL 2021 UA1 – Tony Dunn (Gravity Simulator) 2021 UA1 – David Rankin (Catalina Sky Survey)