19 Aquarii must be rotating at least that fast. 19 Aquarii 19 Aquarii is a star in the constellation of Aquarius. With an apparent magnitude of about 5.7, the star is barely visible to the naked eye (see Bortle scale). Parallax estimates made by the Hipparcos spacecraft put it at a distance of about 300 light years (92 parsecs) away from the Earth. 19 Aquarii has a spectral type of A8V, meaning it is an A-type main-sequence star. These types of stars are bluish-white colored, and have effective temperatures between 7100 and 11500 K. It rotates fairly fast, as its projected rotational
3-j symbol more symmetrical than the C-G coefficient. Since the state formula_5 is unchanged by rotation, one also says that the contraction of the product of three rotational states with a 3-"j" symbol is invariant under rotations. The Wigner 3-"j" symbol is zero unless all these conditions are satisfied: A 3-"j" symbol is invariant under an even permutation of its columns: An odd permutation of the columns gives a phase factor: Changing the sign of the formula_11 quantum numbers (time-reversal) also gives a phase: The 3-"j" symbols also have so-called Regge symmetries, which are not due to permutations or time-reversal. These symmetries