2017 AG13 is a small Aten asteroid that made a close approach of 0.54 lunar distances from Earth on January 9, 2017.[4] It was the largest asteroid to pass less than 1 lunar distance from Earth since 2016 QA2 on August 28, 2016. The Catalina Sky Survey observed it first on January 7, 2017, only two days before its closest approach. At its brightest, 2017 AG13 reached apparent magnitude 12.2.[1][2] Shortly after, it moved too close to the Sun to be seen by telescopes.
The asteroid frequently makes close approaches to Earth, possibly passing as close as 127,000 kilometres (79,000 mi) to Earth on January 9, 2069, however it will most likely pass much farther away.[2][5]
Based on an absolute magnitude of 26.1, 2017 AG13 is likely 15–36 metres (49–118 feet) across, assuming a typical asteroid albedo of between 0.05 and 0.3.[3]
