1. SPH modelling of companion-perturbed AGB outflows including a new morphology classification scheme
- Author
-
Lionel Siess, Leen Decin, J. Bolte, F. De Ceuster, S. Maes, J. Malfait, and W. Homan
- Subjects
Orbital plane ,CIRCUMSTELLAR ENVELOPES ,010504 meteorology & atmospheric sciences ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astronomy & Astrophysics ,Gravitational acceleration ,Computer Science::Digital Libraries ,01 natural sciences ,Wind speed ,DUSTY WINDS ,0103 physical sciences ,Asymptotic giant branch ,Astrophysics::Solar and Stellar Astrophysics ,HYDRODYNAMICAL SIMULATIONS ,ACCRETION ,winds, outflows [stars] ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics ,Astrophysique ,BIPOLAR PREPLANETARY NEBULAE ,0105 earth and related environmental sciences ,Physics ,Science & Technology ,ALMA OBSERVATIONS ,Astrophysics::Instrumentation and Methods for Astrophysics ,Velocity dispersion ,numerical [methods] ,MASS-LOSS ,Astronomy and Astrophysics ,DRIVEN ,AGB and post-AGB [stars] ,Physics::History of Physics ,BINARY-SYSTEMS ,Astrophysics - Solar and Stellar Astrophysics ,13. Climate action ,Space and Planetary Science ,Physical Sciences ,hydrodynamics ,Orbital motion ,Outflow ,Astrophysics::Earth and Planetary Astrophysics ,Planetary mass ,STARS - Abstract
Asymptotic giant branch (AGB) stars are known to lose a significant amount of mass by a stellar wind, which controls the remainder of their stellar lifetime. High angular-resolution observations show that the winds of these cool stars typically exhibit mid- to small-scale density perturbations such as spirals and arcs, believed to be caused by the gravitational interaction with a (sub-)stellar companion. We aim to explore the effects of the wind-companion interaction on the 3D density and velocity distribution of the wind, as a function of three key parameters: wind velocity, binary separation and companion mass. For the first time, we compare the impact on the outflow of a planetary companion to that of a stellar companion. We intend to devise a morphology classification scheme based on a singular parameter. With our grid of models we cover the prominent morphology changes in a companion-perturbed AGB outflow: slow winds with a close, massive binary companion show a more complex morphology. Additionally, we prove that massive planets are able to significantly impact the density structure of an AGB wind. We find that the interaction with a companion affects the terminal velocity of the wind, which can be explained by the gravitational slingshot mechanism. We distinguish between two types of wind focussing to the orbital plane resulting from distinct mechanisms: global flattening of the outflow as a result of the AGB star's orbital motion and the formation of an EDE as a consequence of the companion's gravitational pull. We investigate different morphology classification schemes and uncover that the ratio of the gravitational potential energy density of the companion to the kinetic energy density of the AGB outflow yields a robust classification parameter for the models presented in this paper., 19 pages, 11 figures
- Published
- 2021