Evolution From Asymptotic Giant Branch to Pre-planetary Nebula: Whorled Patterns and Stellar Companions

Fuente: arXiv
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Autore principale: Kim, Hyosun
Natura: Preprint
Pubblicazione: 2024
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author Kim, Hyosun
author_facet Kim, Hyosun
contents Bipolar or multipolar lobes in pre-planetary nebulae (pPNe) often exhibit intertwined outer whorled patterns, resulting from stellar wind matter accumulation during the asymptotic giant branch (AGB) phase. These structures are likely triggered by stellar or substellar companions. We regard that CW Leonis currently stands at a critical transition moment, providing a vivid illustration of the progression from an AGB star in a binary system to a pPN. We have found that CW Leonis has shown significant enhancements in its optical and near-infrared light curves over the past two decades, with the recent Hubble Space Telescope image finally revealing the long-awaited central star. Utilizing an eccentric-orbit binary model, we can reproduce the position-angle dependence of the expansion velocity in the whorled pattern around CW Leonis, suggesting a nearly face-on orbital inclination. Its contradiction to the features in the innermost circumstellar envelope, corresponding to a nearly edge-on inclination, may imply the presence of an additional companion. Our updated theoretical framework explores the complexity of the whorled pattern. Further identifying and monitoring phase-transition candidates at the tip of the AGB will provide valuable insights into the AGB-pPN transition and the role of companions in shaping the morphological evolution of these stellar objects.
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id arxiv_https___arxiv_org_abs_2410_11244
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Evolution From Asymptotic Giant Branch to Pre-planetary Nebula: Whorled Patterns and Stellar Companions
Kim, Hyosun
Solar and Stellar Astrophysics
Astrophysics of Galaxies
Bipolar or multipolar lobes in pre-planetary nebulae (pPNe) often exhibit intertwined outer whorled patterns, resulting from stellar wind matter accumulation during the asymptotic giant branch (AGB) phase. These structures are likely triggered by stellar or substellar companions. We regard that CW Leonis currently stands at a critical transition moment, providing a vivid illustration of the progression from an AGB star in a binary system to a pPN. We have found that CW Leonis has shown significant enhancements in its optical and near-infrared light curves over the past two decades, with the recent Hubble Space Telescope image finally revealing the long-awaited central star. Utilizing an eccentric-orbit binary model, we can reproduce the position-angle dependence of the expansion velocity in the whorled pattern around CW Leonis, suggesting a nearly face-on orbital inclination. Its contradiction to the features in the innermost circumstellar envelope, corresponding to a nearly edge-on inclination, may imply the presence of an additional companion. Our updated theoretical framework explores the complexity of the whorled pattern. Further identifying and monitoring phase-transition candidates at the tip of the AGB will provide valuable insights into the AGB-pPN transition and the role of companions in shaping the morphological evolution of these stellar objects.
title Evolution From Asymptotic Giant Branch to Pre-planetary Nebula: Whorled Patterns and Stellar Companions
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2410.11244