Flores, Brian
(2023)
Spectroscopic Study of Stellar Winds of Massive Stars.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
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Abstract
Massive stars -- greater than 8 solar masses -- are characterized as being very luminous, short lived, and, of most interest, having a continuous outflow of material known as a stellar wind. These winds influence the physics of a star's atmosphere, significantly impacting its surface abundance, chemical profile, and spectral appearance. More importantly, stellar winds are a form of mass loss which substantially influences a star's evolutionary time-scale and its final fate as a neutron star, pulsar, or magnetar after a supernova explosion, or its collapse into a black hole. Within the last few decades, significant advancements in theory and computation have lead to a wealth of knowledge about stellar winds, as well as new questions and challenges yet to be resolved. Examples of such questions are: ``How does the stellar wind's strength change over the massive star's lifetime?''; ``Does the physical characteristic of the stellar wind affect the diagnostic tools that we use?''; ``What flaws do current radiative transfer models of stellar wind exist/ are overlooked?'' My thesis focuses on the spectroscopic study of stellar winds of hot, massive stars, specifically AzV 83 and HD 50896. I use a radiative transfer code, CMFGEN, to calculate stellar wind models and synthesize spectra for comparison with observations. Specifically, I model a more accurate description of the density structure of an inhomogeneous (clumpy) wind. I analyzed a set of well-studied spectroscopic lines, from which we can determine stellar wind parameters (i.e. mass-loss rates and terminal velocities) and ionization structure. Understanding the effects of clumping in winds is critical to our understanding the emergent spectra and to the empirical derivation of mass-loss of massive stars.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
25 January 2023 |
| Date Type: |
Publication |
| Defense Date: |
6 December 2022 |
| Approval Date: |
25 January 2023 |
| Submission Date: |
13 December 2022 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
166 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Physics |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Thesis, Massive Stars, Stellar Winds, Mass Loss, Spectroscopy, Radiative Transfer |
| Date Deposited: |
25 Jan 2023 15:29 |
| Last Modified: |
25 Jan 2023 15:29 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/44015 |
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