Molecular Hydrogen Kinematics and Structure in the Ring Nebula1

• Published in: Publications of the Astronomical Society of the Pacific Vol. 116; no. 826; pp. 1135 - 1142
• Main Author: Hiriart, David
• Format: Journal Article
• Language: English
• Published: The University of Chicago Press 23.11.2004; 01.12.2004
• Subjects: Ellipses; Hydrogen; Kinematics; Molecular evolution; Nebulae; Pollutant emissions; Radial velocity; Ring nebulae; Stars
• ISSN: 0004-6280; 1538-3873
• DOI: 10.1086/426926

This paper presents the radial velocity structure of the molecular hydrogen distribution in the Ring Nebula (NGC 6720). The structure was derived from the Doppler shift of the H2 \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $v=1{\mbox{--}} 0$ \end{document} S(1) line emission (2.122 μm, \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $\Delta \lambda =0.02$ \end{document} μm), obtained using Fabry‐Pérot spectroscopy. The kinematic results point to the fact that the molecular hydrogen emission is concentrated in an expanding hollow cylinder containing H2clumps. In spite of the medium resolution of the observations, the kinematics of the H2clumps in NGC 6720 are revealed, showing that they are distributed all over the ellipsoidal shell, with a wide range of values for their radial velocities and sizes.