A parsec (symbol: pc) is a unit of length that is used in measuring large distances of astronomical objects outside the Solar System. A parsec was defined as the distance at which one astronomical unit subtends an angle of one arcsecond. It was redefined in 2015 to exactly 648,000 astronomical units. One parsec is equal to about 3.26 light-years (30 trillion km or 19 trillion miles) in length. The nearest star, Proxima Centauri, is about 1.3 parsecs (4.2 light-years) from the Sun.
- ↑ "Cosmic Distance Scales - The Milky Way". https://heasarc.gsfc.nasa.gov/docs/cosmic/milkyway_info.html. Retrieved 24 September 2014.
- ↑ Benedict, G. F.. "Astrometric Stability and Precision of Fine Guidance Sensor #3: The Parallax and Proper Motion of Proxima Centauri" (PDF). Proceedings of the HST Calibration Workshop. pp. 380–384. http://clyde.as.utexas.edu/SpAstNEW/Papers_in_pdf/%7BBen93%7DEarlyProx.pdf. Retrieved 11 July 2007.