227AU

227 astronomical units (AU) is a distance unit used in astronomy to describe positions beyond the planetary region of the Solar System. One astronomical unit equals the mean distance between the Earth and the Sun, about 149.6 million kilometres. Therefore, 227 AU is approximately 34 billion kilometres from the Sun.

The outer reaches of the Solar System are traditionally divided into several zones. Within 30 AU lies the Kuiper Belt, populated by icy bodies and dwarf planets. Beyond the Kuiper Belt, from roughly 30 to 200 AU, the scattered disc and the detached objects are found. The heliopause, the outer boundary of the heliosphere where the solar wind is halted by the interstellar medium, has been measured to the nearest of the two NASA Voyager spacecraft at about 121 AU. Hence 227 AU lies well outside the heliopause, in a regime considered part of the local interstellar medium.

Spacecraft such as Voyager 1 and Voyager 2, launched in 1977, have passed 227 AU during their extended missions. Their observations of cosmic rays, magnetic fields, and interplanetary dust at this distance provide insight into the structure of the heliosphere and its interaction with interstellar space. Moreover, the theoretical models of the Oort Cloud, the distant reservoir of comets, extend out to several thousand AU, so 227 AU is within the inner Oort Cloud region.

While 227 AU is not a specific named object, it represents a critical distance scale for understanding the outermost reaches of the Sun’s influence and the transition to interstellar space.