AAS 198th Meeting, June 2001
Session 48. YSOs
Display, Tuesday, June 5, 2001, 10:00am-6:30pm, Exhibit Hall

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[48.10] Old Faithful: Simulation-Based Investigation of an Episodic Jet Formation Model

S. Matt (Univ. of Washington Astronomy Dept.), A. Goodson, R. Winglee (Univ. of Washington Geophysics Dept.), K.H. Bohm (Univ. of Washington Astronomy Dept.)

Goodson, Winglee, and Bohm recently proposed a time-dependent accretion/ejection mechanism that self-consistently explains many observational properties of YSO outflows, involving the interaction of the inner edge of an accretion disk with the rotating magnetic field of the star. With initial conditions typical for T-Tauri stars, the interaction produces a fast (100-200 km s-1), highly collimated jet; knots in the jet with quasi-periodic (10-100 day) spacing; a poorly collimated ``disk wind''; and x-ray flaring of the central source. The large number of parameters and the system's complicated behavior make detailed analytical predictions difficult. For this reason, we have carried out a numerical simulation-based investigation of the model over a limited range of parameters.

Our investigation includes models whose disk densities are different from each other by up to a factor of 16, models whose stellar magnetic field strengths differ by a factor of 4, models with various global magnetic field topologies, and models with different initial locations of the disk inner edge. The new result from these simulations is that the jet launching mechanism is both robust and self-regulating. In all cases, a jet and disk wind is produced, the system is always episodic, and the outflow properties have only a weak dependence on the initial conditions assumed. We present the results of this investigation, focusing primarily on the properties of the outflow (jet + disk wind) for all cases.

This research was supported by NSF grant AST 97-29096.

The author(s) of this abstract have provided an email address for comments about the abstract: matt@astro.washington.edu

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