On an Emerging Paradigm of Tepid Stars: Assessing the Magnetic Desert and the Magnetic Origin of Surprisingly Common Star Spots
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Authors
Sikora, James
Date
Type
thesis
Language
eng
Keyword
astronomy , stars , magnetic fields
Alternative Title
Abstract
The past decade has seen several significant shifts in the field of stellar magnetism, particularly on the observational front. A new generation of dramatically more efficient, high-resolution spectropolarimetric instruments have enabled measurements of magnetic fields hosted by intermediate mass stars to be obtained with unprecedented precision. Moreover, the Kepler and TESS spacecraft have yielded optical light curves that are sensitive to flux variations on the order of parts per million. Both of these advancements have facilitated potentially paradigm shifting discoveries including (1) the emerging picture of a "magnetic dichotomy" in which the magnetic fields hosted by a small fraction of intermediate mass stars are either very prominent (B > 200 G) or ultra-weak (B < 1 G); and (2) that a large fraction of these tepid stars may not be as quiescent as previously believed, as demonstrated by the surprising detection of variability that is consistent with rotational modulation, which is interpreted to be a consequence of magnetic activity. In this thesis, I will present the results obtained from three related studies that have expanded upon these recent discoveries. The first study was designed to test the validity of the magnetic dichotomy and elaborate on properties of the "strong field" population of stars by carrying out a volume-limited survey of magnetic intermediate mass stars within 100 pc. The second study focuses on the unexpected result obtained using Kepler -- the widespread detection of rotationally modulated light curves of A- and B-type stars -- which suggests that a much larger fraction of intermediate mass stars than has previously been believed may be magnetic. The third study consists of a search for A-type stars that exhibit similar rotational modulation in their light curves obtained with the recently launched TESS spacecraft.
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Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.