Spectrum of HO from averaging the four strongest emission lines in the pole region of Fig. 3. The line width (1.01 ± 0.1 km s^-1) is lower than expected for isotropic outgassing at v_exp = 0.70 km s^-1 (FWHM = 1.36 km s^-1 with a double peak, dashed line). If we assume that most of the outgassing is limited to a restricted cone (φ = 90 ± 48°, θ = ± 48°, see text), we obtain a reasonable agreement to the line shape (superimposed continuous profile, with molec s^-1). Part of the background continuum of the nucleus is also seen and modeled.