Wiggled Structure of Herbig-Haro Objects: Helical Kink Instability of Jets from Young Stellar Objects
Abstract
We describe the results of three-dimensional magnetohydrodynamic numerical simulations, as applied to the behavior of the jets from YSO jets under circumstances in which the ambient large-scale interstellar magnetic field is twisted helically by the rotation of the protostar and the protostellar disk through which this field threads. The calculations are continued until the bow shock propagates a distance 60 times as far as the initial jet radius. The specific case we examine involves a jet with density 100 mH/cu cm and velocity 100 km/s; we then show that an azimuthal field of strength 70 micro-G drives a helical kink instability. The growth rate of this instability is large enough that significant morphological effects are expected to be visible during the typical lifetime of an HH object; for example, the observed 'wiggled' appearance of some HH objects may be due to this helical kink instability.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1993
- DOI:
- 10.1086/172191
- Bibcode:
- 1993ApJ...403..164T
- Keywords:
-
- Computational Astrophysics;
- Early Stars;
- Helical Flow;
- Herbig-Haro Objects;
- Jet Flow;
- Magnetohydrodynamic Stability;
- Boundary Conditions;
- Hydrodynamic Equations;
- Protostars;
- Star Formation;
- Stellar Magnetic Fields;
- Astrophysics;
- ISM: JETS AND OUTFLOWS;
- METHODS: NUMERICAL;
- MAGNETOHYDRODYNAMICS: MHD;
- STARS: PRE--MAIN-SEQUENCE