RCW 88 of a larger halo of fainter nebulosity extending perhaps out to 10 arcmin. The RCW catalogue states the Hα image size is 3'×2. RCW 88 is located about 3300 parsecs (10,000 light years) from us, though other estimates place this at a closer 1800±300 pc. or 1800±200 pc. Assuming the former distance and the diameter as 5'-6' across, finds by simple trigonometry the true size subtends a minimum of 5±1 parsecs (16±3 light-years.) This small emission nebula shows a mean radial velocity of −18 km.s, and is also a faint radio source that was identified by Lloyd Higgs in 1971.
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