VLT observations of the asymmetric Etched Hourglass Nebula, MyCn 18

Abstract

Context. The mechanisms that form extreme bipolar planetary nebulae remain unclear. Aims. The physical properties, structure, and dynamics of the bipolar planetary nebula, MyCn 18, are investigated in detail with the aim of understanding the shaping mechanism and evolutionary history of this object. Methods. VLT infrared images, VLT ISAAC infrared spectra, and long-slit optical Echelle spectra are used to investigate MyCn 18. Morpho-kinematic modelling was used to firmly constrain the structure and kinematics of the source. A timescale analysis was used to determine the kinematical age of the nebula and its main components. Results. A spectroscopic study of MyCn 18's central and offset region reveals the detailed make-up of its nebular composition. Molecular hydrogen, atomic helium, and Bracket gamma emission are detected from the central regions of MyCn 18. ISAAC spectra from a slit position along the narrow waist of the nebula demonstrate that the ionised gas resides closer to the centre of the nebula than the molecular emission. A kinematical age of the nebula and its components were obtained by the P-V arrays and timescale analysis. Conclusions. The structure and kinematics of MyCn 18 are better understood using an interactive 3-D modelling tool called shape. A dimensional and timescale analysis of MyCn 18's major components provides a possible mechanism for the nebula's asymmetry. The putative central star is somewhat offset from the geometric centre of the nebula, which is thought to be the result of a binary system. We speculate that the engulfing and destruction of an exoplanet during the AGB phase may have been a key event in shaping MyCn 18 and generating of its hypersonic knotty outflow.

arXiv comment15 pages, 3 tables, 13 figures. Accepted for publication by A&A

References in corpus (23)

• The Origin and Shaping of Planetary Nebulae: Putting the Binary Hypothesis to the Test
• Foretellings of Ragnarök: World-engulfing Asymptotic Giants and the Inheritance of White Dwarfs
• Low-Mass Binary Induced Outflows from Asymptotic Giant Branch Stars
• Shape: A 3D Modeling Tool for Astrophysics
• The Formation of Very Narrow Waist Bipolar Planetary Nebulae
• The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale
• Formation of Bipolar Planetary Nebulae by Intermediate-Luminosity Optical Transients
• Departure from Axisymmetry in Planetary Nebulae
• The role of planets in shaping planetary nebulae
• Abell 41: shaping of a planetary nebula by a binary central star?
• A Detailed Morpho-Kinematic Model of the Eskimo, NGC 2392. A Unifying View with the Cat's Eye and Saturn Planetary Nebulae
• Disentangling telluric lines in stellar spectra
• VLT / Infrared Integral Field Spectrometer Observations of Molecular Hydrogen Lines in the Knots in the Planetary Nebula NGC 7293 (the Helix Nebula)
• The morphology and kinematics of the Fine Ring Nebula, planetary nebula Sp 1, and the shaping influence of its binary central star
• Molecular Hydrogen in the Ionized Region of Planetary Nebulae
• Merged ionization/dissociation fronts in planetary nebulae
• Magnetic fields in central stars of planetary nebulae?
• A study of the kinematics and binary-induced shaping of the planetary nebula HaTr 4
• Discovery of Multiple Shells Around the Planetary Nebula IC 418
• Sculpting an AGB Mass-Loss Envelope into a Bipolar Planetary Nebula: High-Velocity Outflows in V Hydrae
• The Unusual Distributions of Ionized Material and Molecular Hydrogen in NGC 6881: Signposts of Multiple Events of Bipolar Ejection in a Planetary Nebula
• A Detailed Spatiokinematic Model of the Conical Outflow of the Multipolar Planetary Nebula, NGC 7026
• Kn 26, a New Quadrupolar Planetary Nebula

Cited by in corpus (9)

• The jet feedback mechanism (jfm) in stars, galaxies and clusters
• A morpho-kinematic and spectroscopic study of the bipolar nebulae: M 2-9, Mz 3, and Hen 2-104
• Operation of the jet feedback mechanism (JFM) in intermediate luminosity optical transients (ILOTs)
• Deciphering the bipolar planetary nebula Abell 14 with 3D ionization and morphological studies
• Giant planet engulfment by evolved giant stars: light curves, asteroseismology, and survivability
• Energy Budget and Core-Envelope Motion in Common Envelope Evolution
• Distance mapping applied to four well-known planetary nebulae and a nova shell
• The morpho-kinematical structure and chemical abundances of the complex planetary nebula NGC 1514
• The Effect of the Slit Configuration on the H${}_2$ 1-0~S(1) to Br$\gamma$ Line Ratio of Spatially Resolved Planetary Nebulae