{"id":{"repo_id":"ohiolink","oai_identifier":"oai:etd.ohiolink.edu:toledo1365171803"},"canonical_url":"https://search.dev.ndltd.org/etd/ohiolink/oai:etd.ohiolink.edu:toledo1365171803","repository":{"repo_id":"ohiolink","name":"OhioLINK","base_url":"https://etd.ohiolink.edu/acprod/odb_etd/ws/oai/oai"},"display":{"title":"A New Era of Observational Capability at Ritter Observatory: Spectropolarimetry from Exoplanets to Circumstellar Disks and Beyond","abstract":"We undertook efforts to restore and relocate the University of Wisconsin's Halfwave-Polarimeter (HPOL) spectropolarimeter to the University of Toledo's Ritter Observatory. This process required fairly extensive work to the optical-mechanical alignment of the Ritter Observatory 1-meter telescope. Ultimately the restoration and relocation efforts were successful, with first light at Ritter Observatory on March 11th, 2012. Extensive observations of unpolarized standard stars were carried out in the first six months of observing time at Ritter Observatory. The results of this effort has shown the polarimetric stability in the observations is at the same level or better compared to almost 10 years of observations at Pine Bluff Observatory, after the upgrade to the detector.Aside from continued spectropolarimetric monitoring programs which were initially focused on a selection of Be and Wolf-Rayet stars, we sought to investigate potential polarimetric variability in exoplanet systems. In particular we focused on the system HD189733, as there was previous observational work in the literature claiming both a detection and non-detection at different optical wavelengths. The goal was to investigate this system with HPOL to provide simultaneous observations across the entire optical wavelength range to investigate the possibility of a wavelength dependent variable polarization with orbital phase. While the variability claimed in the literature is below the noise limits of our observations, an interesting and yet unexplained increase in the polarization level occurred in one of our observations. This higher than expected signal had vanished by the next observation, which was several nights later due to weather, and did not reappear in any of the observations thereafter, implying such a higher than expected signal must be short lived, lasting less than a couple orbital periods. This increase is around an order of magnitude larger than the claimed detection in the literature from light scattering off the exoplanets atmosphere, and would seem to be caused by some other physical mechanism in the system. Continued observations of HD189733 with HPOL in the next observing season starting in July 2013 will help to identify if the increased polarization level is repeatable.","abstract_html":"We undertook efforts to restore and relocate the University of Wisconsin's Halfwave-Polarimeter (HPOL) spectropolarimeter to the University of Toledo's Ritter Observatory. This process required fairly extensive work to the optical-mechanical alignment of the Ritter Observatory 1-meter telescope. Ultimately the restoration and relocation efforts were successful, with first light at Ritter Observatory on March 11th, 2012. Extensive observations of unpolarized standard stars were carried out in the first six months of observing time at Ritter Observatory. The results of this effort has shown the polarimetric stability in the observations is at the same level or better compared to almost 10 years of observations at Pine Bluff Observatory, after the upgrade to the detector.Aside from continued spectropolarimetric monitoring programs which were initially focused on a selection of Be and Wolf-Rayet stars, we sought to investigate potential polarimetric variability in exoplanet systems. In particular we focused on the system HD189733, as there was previous observational work in the literature claiming both a detection and non-detection at different optical wavelengths. The goal was to investigate this system with HPOL to provide simultaneous observations across the entire optical wavelength range to investigate the possibility of a wavelength dependent variable polarization with orbital phase. While the variability claimed in the literature is below the noise limits of our observations, an interesting and yet unexplained increase in the polarization level occurred in one of our observations. This higher than expected signal had vanished by the next observation, which was several nights later due to weather, and did not reappear in any of the observations thereafter, implying such a higher than expected signal must be short lived, lasting less than a couple orbital periods. This increase is around an order of magnitude larger than the claimed detection in the literature from light scattering off the exoplanets atmosphere, and would seem to be caused by some other physical mechanism in the system. Continued observations of HD189733 with HPOL in the next observing season starting in July 2013 will help to identify if the increased polarization level is repeatable.","abstract_has_math":false,"creators":["Davidson, James W., Jr."],"institution":"University of Toledo","degree_name":"Doctor of Philosophy","degree_level":"doctoral","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Bjorkman, Karen"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-07-11","date_published":"2013-07-11","updated_at":"2026-07-24T03:37:16Z","subjects":["Astronomy","Physics","Astrophysics"],"languages":["English"],"rights":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://rave.ohiolink.edu/etdc/view?acc_num=toledo1365171803","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Bjorkman, Karen"]},{"key":"dc:creator","label":"Author","values":["Davidson, James W., Jr."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2013-07-11"]},{"key":"dc:publisher","label":"Institution","values":["University of Toledo / OhioLINK"]},{"key":"dc:type","label":"Dc Type","values":["Electronic Thesis or Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Toledo"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Astronomy","Physics","Astrophysics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:rights","label":"Dc Rights","values":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://rave.ohiolink.edu/etdc/view?acc_num=toledo1365171803"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["We undertook efforts to restore and relocate the University of Wisconsin's Halfwave-Polarimeter (HPOL) spectropolarimeter to the University of Toledo's Ritter Observatory. This process required fairly extensive work to the optical-mechanical alignment of the Ritter Observatory 1-meter telescope. Ultimately the restoration and relocation efforts were successful, with first light at Ritter Observatory on March 11th, 2012. Extensive observations of unpolarized standard stars were carried out in the first six months of observing time at Ritter Observatory. The results of this effort has shown the polarimetric stability in the observations is at the same level or better compared to almost 10 years of observations at Pine Bluff Observatory, after the upgrade to the detector.Aside from continued spectropolarimetric monitoring programs which were initially focused on a selection of Be and Wolf-Rayet stars, we sought to investigate potential polarimetric variability in exoplanet systems. In particular we focused on the system HD189733, as there was previous observational work in the literature claiming both a detection and non-detection at different optical wavelengths. The goal was to investigate this system with HPOL to provide simultaneous observations across the entire optical wavelength range to investigate the possibility of a wavelength dependent variable polarization with orbital phase. While the variability claimed in the literature is below the noise limits of our observations, an interesting and yet unexplained increase in the polarization level occurred in one of our observations. This higher than expected signal had vanished by the next observation, which was several nights later due to weather, and did not reappear in any of the observations thereafter, implying such a higher than expected signal must be short lived, lasting less than a couple orbital periods. This increase is around an order of magnitude larger than the claimed detection in the literature from light scattering off the exoplanets atmosphere, and would seem to be caused by some other physical mechanism in the system. Continued observations of HD189733 with HPOL in the next observing season starting in July 2013 will help to identify if the increased polarization level is repeatable."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf","p.164","12.37 MB"]},{"key":"dc:title","label":"Title","values":["A New Era of Observational Capability at Ritter Observatory: Spectropolarimetry from Exoplanets to Circumstellar Disks and Beyond"]}]}],"canonical_facts":{"dc:contributor":["Bjorkman, Karen"],"dc:creator":["Davidson, James W., Jr."],"dc:date":["2013-07-11"],"dc:description":["We undertook efforts to restore and relocate the University of Wisconsin's Halfwave-Polarimeter (HPOL) spectropolarimeter to the University of Toledo's Ritter Observatory. This process required fairly extensive work to the optical-mechanical alignment of the Ritter Observatory 1-meter telescope. Ultimately the restoration and relocation efforts were successful, with first light at Ritter Observatory on March 11th, 2012. Extensive observations of unpolarized standard stars were carried out in the first six months of observing time at Ritter Observatory. The results of this effort has shown the polarimetric stability in the observations is at the same level or better compared to almost 10 years of observations at Pine Bluff Observatory, after the upgrade to the detector.Aside from continued spectropolarimetric monitoring programs which were initially focused on a selection of Be and Wolf-Rayet stars, we sought to investigate potential polarimetric variability in exoplanet systems. In particular we focused on the system HD189733, as there was previous observational work in the literature claiming both a detection and non-detection at different optical wavelengths. The goal was to investigate this system with HPOL to provide simultaneous observations across the entire optical wavelength range to investigate the possibility of a wavelength dependent variable polarization with orbital phase. While the variability claimed in the literature is below the noise limits of our observations, an interesting and yet unexplained increase in the polarization level occurred in one of our observations. This higher than expected signal had vanished by the next observation, which was several nights later due to weather, and did not reappear in any of the observations thereafter, implying such a higher than expected signal must be short lived, lasting less than a couple orbital periods. This increase is around an order of magnitude larger than the claimed detection in the literature from light scattering off the exoplanets atmosphere, and would seem to be caused by some other physical mechanism in the system. Continued observations of HD189733 with HPOL in the next observing season starting in July 2013 will help to identify if the increased polarization level is repeatable."],"dc:format":["application/pdf","p.164","12.37 MB"],"dc:identifier":["http://rave.ohiolink.edu/etdc/view?acc_num=toledo1365171803"],"dc:language":["English"],"dc:publisher":["University of Toledo / OhioLINK"],"dc:rights":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."],"dc:subject":["Astronomy","Physics","Astrophysics"],"dc:title":["A New Era of Observational Capability at Ritter Observatory: Spectropolarimetry from Exoplanets to Circumstellar Disks and Beyond"],"dc:type":["Electronic Thesis or Dissertation"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["University of Toledo"]},"updated_at":"2026-07-24T03:37:16Z"}