Time-dependent ejection velocity model for the outflow of Hen 3-1475^*

¹ Instituto de Ciencias Nucleares, UNAM, Ciudad Universitaria, Apdo. Postal 70-543, CP 04510, Mexico D.F., Mexico e-mail: raga@nuclecu.unam.mx
² Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Escola Universitària Politècnica de Vilanova i La Geltrú, Av. Víctor Balaguer s/n, 08800 Vilanova i la Geltrú, Spain e-mail: angels.riera@upc.es
³ Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona, Spain

Corresponding author: P. F. Velázquez, pablo@nuclecu.unam.mx

Received: 28 November 2003
Accepted: 25 February 2004

Abstract

We present 2D axisymmetric and 3D numerical simulations of the proto-planetary nebula Hen 3-1475, which is characterized by a remarkably highly collimated optical jet, formed by a string of shock-excited knots along the axis of the nebula. It has recently been suggested that the kinematical and morphological properties of the Hen 3-1475 jet could be the result of an ejection variability of the central source (Riera et al. [CITE]). The observations suggest a periodic variability of the ejection velocity superimposed on a smoothly increasing ejection velocity ramp. From our numerical simulations, we have obtained intensity maps (for different optical emission lines) and position-velocity diagrams, in order to make a direct comparison with the HST observations of this object. Our numerical study allows us to conclude that a model of a precessing jet with a time-dependent ejection velocity, which is propagating into an ISM previously perturbed by an AGB wind, can succesfully explain both the morphological and the kinematical characteristics of this proto-planetary nebula.