U is a possible object detected by the Atacama Large Millimeter Array (ALMA) during a survey for substellar objects in the Alpha Centauri system. In images taken on 7 July 2014 (343.5 GHz) and 2 May 2015 (445 GHz), researchers discovered a source in the far infrared located within 5.5 arcseconds of α Cen AB. Based on its proper motion, it was at first thought to be a part of the Alpha Centauri system. Further analysis, however, found that the object must be closer to the Solar System, and that it may be gravitationally bound to the Sun. The researchers suggest that the object may be an extreme trans-Neptunian object (ETNO) beyond 100 AU (15 billion kilometres), a super-Earth at around 300 AU (45 billion kilometres), or a very cool brown dwarf at around 20,000 astronomical units (3.0 trilli