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 and formula_21 integers. Similar relations exist for the spin-weighted spherical harmonics if formula_22: For formula_25 a non-zero 3-"j" symbol has where formula_27 and formula_28 is a Wigner function. Generally a better approximation obeying the Regge symmetry is given by where formula_30. The following quantity acts as a metric tensor in angular momentum theory and is also known as a "Wigner 1-jm symbol", It can be used to perform time-reversal on angular momenta. Wigner 3-j symbols are related to Racah -coefficients by a simple phase: 3-j symbol In quantum mechanics, the Wigner 3-j symbols, also called 3"-jm" symbols, are an alternative