The Mechanism of Interacting Stellar Winds beyond Red Giant Branch

Sundus A Abdullah Albakri,Sinan H Ali

doi:10.4236/ijaa.2013.34041

Sundus A Abdullah Albakri, Sinan H Ali

Open Access

https://doi.org/10.4236/ijaa.2013.34041

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Abstract

The dynamical processes of the interaction of slow wind beyond Red Giant phase with fast wind of central star of nebula are evaluated. The mechanism of interaction stellar wind model (ISW) is found to be responsible for producing a relatively dense shell of gas which increases in mass and radius at a constant rate. Both slow wind and superwind are assumed to be time independent and radial density is calculated at initial time to ~ 60 yrs with the fast wind velocity (v ≈ 1000 km/s). The results showed that, at the outer rim of super wind region, a small density hump appears due to the relative velocity between slow winds and central star winds, in a good agreement with the previous models. The dynamical requirements of the observed expansion of planetary nebulae can be satisfied by the mechanism of interacting stellar wind model with reasonable mass loss rate from central star.

Highlights

It is widely accepted that Red Giant Branch (RGB) is the progenitors of the nebulae but the details of the transition from one type of objecting the other are not known [1,2]
It is significant that appreciable mass loss which occurs from red giant producing an extensive circumstellar envelope has become “visible” with the advent of IR and Microwaves techniques [7]
The mass loss rates used are based on empirical determinations for the slow wind and fast wind interaction

Summary

Introduction

It is widely accepted that Red Giant Branch (RGB) is the progenitors of the nebulae but the details of the transition from one type of objecting the other are not known [1,2]. Given the short transition time scale, the extensive circumstellar envelope created by steady mass loss during the AGB should not be neglected in the treatment of the formation process of PN, regardless of the ejection mechanism [1,8]. We shall attempt to demonstrate from calculations that there exists direct relation between Red Giant (RG) and Planetary Nebulae (PN) and to discuss a possible evolutionary scenario of the transition of RG into PN

Basic Considerations of the Model and Calculations

Discussion and Conclusions