Striations in molecular clouds: "hearing" the 3D shape of Musca
Abstract
Dust continuum and molecular observations of the low column density parts of molecular clouds have revealed the presence of elongated structures which appear to be well aligned with the magnetic field. These so-called striations are remarkably ordered structures in otherwise chaotic-looking clouds, so understanding their physical origin and the information they encode is expected to be revealing of the properties of their parent clouds. We probe possible mechanisms of striation formation through a series of ideal magnetohydrodynamic simulations. We demonstrate that magnetosonic waves, ubiquitous in molecuar clouds, are the most probable cause of striations, since they are the only mechanism that can reproduce quantitatively their observed properties. If indeed striations are the interstellar ripples caused by the passage of magnetosonic waves, then profound consequences are implied for their ability to reveal hidden, important information about molecular clouds. I will present a specific example: striations in the Musca molecular cloud are found to encode normal modes of the cloud's global magnetosonic vibrations, allowing the reconstruction of it's 3D shape.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E3341T