The lines have been reported by
(1) D. T. Halfen, A. J. Apponi, and L. M. Ziurys, 2002, Astrophys. J. 577, L67.
The dipole moment is from an ab initio calculation mentioned in (1). A recent ab initio paper by
(2) A. Papakondylis and A. Mavrides, 2003, J. Phys. Chem. A 107, 7650
suggests the dipole moment to be smaller by about 0.5 to 1.0 D.