Shifting the Starspot Paradigm through Imaging Magnetic Structures and Evolution.
dc.contributor.author | Roettenbacher, Rachael M. | |
dc.date.accessioned | 2016-06-10T19:32:59Z | |
dc.date.available | NO_RESTRICTION | |
dc.date.available | 2016-06-10T19:32:59Z | |
dc.date.issued | 2016 | |
dc.date.submitted | 2016 | |
dc.identifier.uri | https://hdl.handle.net/2027.42/120865 | |
dc.description.abstract | Magnetism is present in stars across all masses and evolutionary states. For cool stars with a convective outer envelope, stellar magnetic fields are generated through complex interactions between the convective layer and radiative core due to rotation. Magnetism in cool stars fuels stellar activity, in particular as starspots. Using starspots as a proxy, this work concentrates on imaging stellar magnetism. With state-of-the-art observations and imaging techniques, I investigate shifting the spot paradigm of localized starspots blemishing an otherwise bright surface (analogous to the solar photosphere) to a surface hosting a widespread network of magnetically-suppressed convection. This network is capable of affecting measurements of fundamental stellar parameters, such as radius and temperature, leading to inaccurate mass and age estimates. To accomplish this shift, I use precision Kepler data and a light-curve inversion algorithm for studies of stellar differential rotation and starspot evolution. Additionally, with long-baseline interferometric data collected with the Michigan Infrared Combiner (MIRC) at Georgia State University's Center for High Angular Resolution Astronomy (CHARA) Array, I target the bright, spotted, giant primary stars of close binary (RS CVn) systems. For these stars, I combine interferometric detections with radial velocity data to measure orbital and stellar parameters, which are used in concert with long-term photometric light curves to observe ellipsoidal variations, measure gravity darkening, and isolate the starspot signatures. In direct imaging using the interferometric data, I observe a spotted RS CVn star through an entire rotation period to detect canonical starspots, a polar starspot, and globally-suppressed convection. The regions of magnetically-suppressed convection cover a large fraction of the surface, potentially impacting estimates of stellar parameters. The combination of these efforts provides a start to a new era of detailed imaging and understanding of stellar magnetism, which will impact stellar evolution, star and planet formation, and planetary studies. | |
dc.language.iso | en_US | |
dc.subject | imaging starspots | |
dc.title | Shifting the Starspot Paradigm through Imaging Magnetic Structures and Evolution. | |
dc.type | Thesis | en_US |
dc.description.thesisdegreename | PhD | |
dc.description.thesisdegreediscipline | Astronomy and Astrophysics | |
dc.description.thesisdegreegrantor | University of Michigan, Horace H. Rackham School of Graduate Studies | |
dc.contributor.committeemember | Monnier, John D | |
dc.contributor.committeemember | Adams, Fred C | |
dc.contributor.committeemember | Aarnio, Alicia Nicole | |
dc.contributor.committeemember | Calvet, Nuria P | |
dc.contributor.committeemember | Cowley, Charles R | |
dc.subject.hlbsecondlevel | Astronomy | |
dc.subject.hlbtoplevel | Science | |
dc.description.bitstreamurl | http://deepblue.lib.umich.edu/bitstream/2027.42/120865/1/rmroett_1.pdf | |
dc.owningcollname | Dissertations and Theses (Ph.D. and Master's) |
Files in this item
Remediation of Harmful Language
The University of Michigan Library aims to describe library materials in a way that respects the people and communities who create, use, and are represented in our collections. Report harmful or offensive language in catalog records, finding aids, or elsewhere in our collections anonymously through our metadata feedback form. More information at Remediation of Harmful Language.
Accessibility
If you are unable to use this file in its current format, please select the Contact Us link and we can modify it to make it more accessible to you.