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Spectroscopic Study of Stellar Winds of Massive Stars

Flores, Brian (2023) Spectroscopic Study of Stellar Winds of Massive Stars. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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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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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Flores, BrianBLF40@PITT.EDUBLF40
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairHillier, Desmond
Committee MemberBadenes,
Committee MemberBezanson,
Committee MemberBatell,
Committee MemberKoenigsberger,
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


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