Document Type


Date of Degree

Spring 2011

Degree Name

PhD (Doctor of Philosophy)

Degree In


First Advisor

Mutel, Robert

First Committee Member

Gayley, Kenneth

Second Committee Member

Spangler, Steven

Third Committee Member

Lang, Cornelia

Fourth Committee Member

Magnotta, Vincent


Our understanding of the magnetic fields of stars is nearly monopolized by knowledge of our own sun. Very-long baseline radio interferometry (VLBI) provides a means of directly imaging the radio coronae of other stars at a high enough resolution to discern discrete features, something not possible with other observational methods. It also allows the highest positional accuracy of any observational method available. This thesis details the VLBI study of two nearby radio-loud stars in close binary systems. Both systems were observed at numerous epochs spaced over a range of several months with the global-scale radio interferometer array the VLBA-HSA. These observations were combined with archival data from the National Radioastronomy Observatory (NRAO) Archive. The resulting positions, as well as previously published positions, were used to calculate a least-squares solution for all the orbital and astrometric parameters of both systems. This made it possible to determine the position of the physical star with respect to the radio emission in each image. The images of both stars were found to conform to theoretical emission produced by a model dipolar magnetosphere with a filled or partially-filled coronal loop.


Magnetic, Radio, Stellar


viii, 108 pages


Includes bibliographical references (pages 97-108).


Copyright 2011 William Mathew Peterson

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