2021 TP21

 is an Apophis-sized asteroid that was discovered on 11 October 2021 when it was 0.5 AU from Earth. This potentially hazardous asteroid (PHA) spends most or its orbit closer to 4 AU from the Sun as objects orbit more slowly when near aphelion (furthest distance from the Sun). was rated with a Torino scale of 1 from 31 October 2021 to 4 November 2021 for a potential impact on 27 March 2081. As the observation arc became longer the nominal distance from Earth became further on the potential impact date.