Striations in the Taurus molecular cloud: Kelvin-Helmholtz instability or MHD waves?

Abstract

The origin of striations aligned along the local magnetic field direction in the translucent envelope of the Taurus molecular cloud is examined with new observations of 12CO and 13CO J=2-1 emission obtained with the 10~m submillimeter telescope of the Arizona Radio Observatory. These data identify a periodic pattern of excess blue and redshifted emission that is responsible for the striations. For both 12CO and 13CO, spatial variations of the J=2-1 to J=1-0 line ratio are small and are not spatially correlated with the striation locations. A medium comprised of unresolved CO emitting substructures (cells) with a beam area filling factor less than unity at any velocity is required to explain the average line ratios and brightness temperatures. We propose that the striations result from the modulation of velocities and the beam filling factor of the cells as a result of either the Kelvin-Helmholtz instability or magnetosonic waves propagating through the envelope of the Taurus molecular cloud. Both processes are likely common features in molecular clouds that are sub-Alfvenic and may explain low column density, cirrus-like features similarly aligned with the magnetic field observed throughout the interstellar medium in far-infrared surveys of dust emission.

arXiv comment11 pages, 4 figures. Accepted for publication in MNRAS

References in corpus (18)

• A computer program for fast non-LTE analysis of interstellar line spectra
• A model for atomic and molecular interstellar gas: The Meudon PDR code
• The Universality of Turbulence in Galactic Molecular Clouds
• Large-Scale Structure of the Molecular Gas in Taurus Revealed by High Linear Dynamic Range Spectral Line Mapping
• 9286 Stars: An Agglomeration of Stellar Polarization Catalogs
• Planck intermediate results. XXXV. Probing the role of the magnetic field in the formation of structure in molecular clouds
• The relation between gas and dust in the Taurus Molecular Cloud
• Magnetically Aligned HI Fibers and the Rolling Hough Transform
• The Magnetic Field in Taurus Probed by Infrared Polarization
• Magnetically Aligned Velocity Anisotropy in the Taurus Molecular Cloud
• The Five College Radio Astronomy Observatory CO Mapping Survey of the Taurus Molecular Cloud
• Waves on the surface of the Orion molecular cloud
• Trans-Alfvenic Motions in the Taurus Molecular Cloud
• Velocity Anisotropy as a Diagnostic of the Magnetization of the Interstellar Medium and Molecular clouds
• Linear Graviational Instability of Filamentary and Sheet-like Molecular Clouds with Magnetic Fields
• The Kelvin-Helmholtz instability in Orion: a source of turbulence and chemical mixing
• Modelling ripples in Orion with coupled dust dynamics and radiative transfer
• Long-lived Magnetic-Tension-Driven Modes in a Molecular Cloud

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