A Parsec (9,460,528,405,000 km) is the distance where one astronomical units subtends an angle of one arcsecond.
One Parsec is approximately equal to:
A parsec was traditionally defined as the distance where one astronomical unit subtends an angle of one arcsecond. A parsec was redefined in 2015 to `648000/?` astronomical units. Proxima Centauri, is the nearest star to the Sun and is approximately 1.3 parsecs (4.2 light-years) from the Sun.
This unit is often used in astronomy calculations when more conventional units such as kilometers are too small for easy comprehension, and the conversion from common length units to astronomical units is a simple linear transform.