Two-dimensional models of stellar wind bubbles. II - Variable mass-loss rates and the possibility of outer-shell fragmentation in relation to the origin of interstellar bullets.
Abstract
The formation and evolution of stellar-wind bubbles (SWBs) are investigated by means of numerical simulations using the second-order two-dimensional hydrodynamic code of Rozyczka (1985). The observational evidence for variable winds, self-confining flows, and the possibility of bow shocks in Herbig-Haro objects (HHs) is reviewed, and the simulation results are presented graphically and discussed. High-density models are found to produce more rapidly propagating disruptions in the SWBs, with fragments similar to the interstellar bullets proposed to explain the origin of HHs. In T-Tau-like models with compact circumstellar disks, SWBs break out to form secondary SWBs and/or hollow cylinders. Models constructed to explore the shocked-cloudlet hypothesis for HH formation (with winds in excess of Mach 50) are found to become sensitive to cooling efficiency when cooling is taken into account, and to yield predictions which are also consistent with the interstellar-bullet hypothesis.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 1985
- Bibcode:
- 1985A&A...147..202R
- Keywords:
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- Herbig-Haro Objects;
- Magnetohydrodynamic Stability;
- Stellar Mass Ejection;
- Stellar Models;
- Stellar Winds;
- Two Dimensional Models;
- Computational Astrophysics;
- Luminosity;
- Plasma Bubbles;
- Stellar Evolution;
- Astrophysics