The astronomical unit (symbol: au or ua) is a unit of length, roughly the distance from Earth to the Sun. It is presently defined as exactly 149597870700 metres (about 150 million kilometres, or 93 million miles). The astronomical unit is used primarily as a convenient yardstick for measuring distances within the Solar System or around other stars. It is also a fundamental component in the definition of another astronomical length, the parsec.
- ↑ International Astronomical Union, ed. (31 August 2012), "RESOLUTION B2 on the re-definition of the astronomical unit of length", RESOLUTION B2, Beijing, China: International Astronomical Union, "The XXVIII General Assembly of International Astronomical Union … recommends … 5. that the unique symbol "au" be used for the astronomical unit."
- ↑ "Monthly Notices of the Royal Astronomical Society: Instructions for Authors". Oxford Journals. http://www.oxfordjournals.org/our_journals/mnras/for_authors/#6.4%20Miscellaneous%20journal%20style. Retrieved on 2015-03-20. ""The units of length/distance are Å, nm, µm, mm, cm, m, km, au, light-year, pc."
- ↑ "Manuscript Preparation: AJ & ApJ Author Instructions". American Astronomical Society. http://aas.org/authors/manuscript-preparation-aj-apj-author-instructions#_Toc2.2. Retrieved on 2016-10-29. ""Use standard abbreviations for SI... and natural units (e.g., au, pc, cm).""
- ↑ ISO 80000-3, Quantities and units – Space and time
- ↑ International Astronomical Union, ed. (31 August 2012), "RESOLUTION B2 on the re-definition of the astronomical unit of length", RESOLUTION B2, Beijing, Kina: International Astronomical Union, "The XXVIII General Assembly of International Astronomical Union recommends [adopted] that the astronomical unit be re-defined to be a conventional unit of length equal to exactly Template:Val metres, in agreement with the value adopted in IAU 2009 Resolution B2"