2.639 au to light year conversion result above is displayed in three different forms: as a decimal (which could be rounded), in scientific notation (scientific form, standard index form or standard form in the United Kingdom) and as a fraction (exact result). Every display form has its own advantages and in different situations particular form is more convenient than another. For example usage of scientific notation when working with big numbers is recommended due to easier reading and comprehension. Usage of fractions is recommended when more precision is needed.
If we want to calculate how many Light Years are 2.639 Astronomical Units we have to multiply 2.639 by 6830953 and divide the product by 431996825232. So for 2.639 we have: (2.639 × 6830953) ÷ 431996825232 = 18026884.967 ÷ 431996825232 = 4.1729207054517E-5 Light Years
So finally 2.639 au = 0.000041729207054517 light year
