Analysis of Internal Motions in the Halo Planetary Nebula H4-1

ABSTRACT Up to now, 10 planetary nebulae have been regarded as halo planetary nebulae (halo PNe). We obtained low‐ and moderate‐dispersion spectra of the spatially resolved halo planetary nebula H4‐1 in the wavelength region of 3700–6800 A with the Cassegrain Spectrograph of the 74 inch telescope. At moderate dispersions, we were able to observe [O iii] λλ4959, 5007 and Hα of H4‐1 at several position angles (P.A.). We assumed that the widths of these emission‐line profiles were due to Doppler broadening and that these emission lines were composed of several Gaussian components. Multiple Gaussian deconvolution analysis of such emission lines indicated H4‐1 has broad wing components (∼600 km s−1) at P.A. 135° and 180°. We think H4‐1 has a “bipolar flow” between P.A. 135° and 180°. From low‐dispersion spectra, we confirm that H4‐1 is a metal‐poor PN. In spite of the lack of spatially resolved images at present, we believe that H4‐1 has a bipolar flow and that its axis is almost parallel to the line of sight,...