{"id":{"repo_id":"ubc","oai_identifier":"oai:circle.library.ubc.ca:2429/1570"},"canonical_url":"https://search.dev.ndltd.org/etd/ubc/oai:circle.library.ubc.ca:2429/1570","repository":{"repo_id":"ubc","name":"University of British Columbia","base_url":"http://circle.library.ubc.ca/oai/request"},"display":{"title":"Differential polarization of Hβ in γ CAS","abstract":"High resolution ( 0.15 Å/pixel ) spectropolarimetry across the Hβ emission line of the Be star γ Cas is presented. The differential polarization and polarization angle vary both in profile and depth. It was found that the polarization profile fits the relation PL, = (Iunderlying / Itotal)Pc, instead of the generally accepted PL = PC / Iemmission (Coyne 1975). Assuming the absolute polarization in the adjoining continuum is constant, the polarization profile is used to determine Teff, geff, and v sin i for the underlying star by fitting the Hubeny (1988) atmosphere model. The Be star model developed by Poeckert and Marlborough (1978a) for γ Cas is used as a basis to explain our polarization observations. We have made two types of modifications to the model: the first being to revise the intrinsic properties of the underlying star; the other is to make more accurate treatment of the radiation transfer equation in the disk. A search of the parameter space was made to find the best fit. We find an adequate fit to the emission line profile, but only a poor fit to the polarization profile from Poeckert and Marlborough model.","abstract_html":"High resolution ( 0.15 Å/pixel ) spectropolarimetry across the Hβ emission line of the Be star γ Cas is presented. The differential polarization and polarization angle vary both in profile and depth. It was found that the polarization profile fits the relation PL, = (Iunderlying / Itotal)Pc, instead of the generally accepted PL = PC / Iemmission (Coyne 1975). Assuming the absolute polarization in the adjoining continuum is constant, the polarization profile is used to determine Teff, geff, and v sin i for the underlying star by fitting the Hubeny (1988) atmosphere model. The Be star model developed by Poeckert and Marlborough (1978a) for γ Cas is used as a basis to explain our polarization observations. We have made two types of modifications to the model: the first being to revise the intrinsic properties of the underlying star; the other is to make more accurate treatment of the radiation transfer equation in the disk. A search of the parameter space was made to find the best fit. We find an adequate fit to the emission line profile, but only a poor fit to the polarization profile from Poeckert and Marlborough model.","abstract_has_math":false,"creators":["Jiang, Yiman"],"institution":"University of British Columbia","degree_name":"Master of Science - MSc","degree_level":"master's","degree_discipline":"Astronomy","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1993,"date_issued":"1993","date_published":"1993","updated_at":"2026-07-24T05:07:26Z","subjects":[],"languages":["eng"],"rights":["For non-commercial purposes only, such as research, private study and education. 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Assuming the absolute polarization in the adjoining continuum is constant, the polarization profile is used to determine Teff, geff, and v sin i for the underlying star by fitting the Hubeny (1988) atmosphere model. The Be star model developed by Poeckert and Marlborough (1978a) for γ Cas is used as a basis to explain our polarization observations. We have made two types of modifications to the model: the first being to revise the intrinsic properties of the underlying star; the other is to make more accurate treatment of the radiation transfer equation in the disk. A search of the parameter space was made to find the best fit. We find an adequate fit to the emission line profile, but only a poor fit to the polarization profile from Poeckert and Marlborough model."]},{"key":"dc:format","label":"Dc Format","values":["3388812","application/pdf"]},{"key":"dc:title","label":"Title","values":["Differential polarization of Hβ in γ CAS"]}]}],"canonical_facts":{"dc:creator":["Jiang, Yiman"],"dc:date":["1993"],"dc:description":["High resolution ( 0.15 Å/pixel ) spectropolarimetry across the Hβ emission line of the Be star γ Cas is presented. The differential polarization and polarization angle vary both in profile and depth. It was found that the polarization profile fits the relation PL, = (Iunderlying / Itotal)Pc, instead of the generally accepted PL = PC / Iemmission (Coyne 1975). Assuming the absolute polarization in the adjoining continuum is constant, the polarization profile is used to determine Teff, geff, and v sin i for the underlying star by fitting the Hubeny (1988) atmosphere model. The Be star model developed by Poeckert and Marlborough (1978a) for γ Cas is used as a basis to explain our polarization observations. We have made two types of modifications to the model: the first being to revise the intrinsic properties of the underlying star; the other is to make more accurate treatment of the radiation transfer equation in the disk. A search of the parameter space was made to find the best fit. We find an adequate fit to the emission line profile, but only a poor fit to the polarization profile from Poeckert and Marlborough model."],"dc:format":["3388812","application/pdf"],"dc:identifier":["http://hdl.handle.net/2429/1570","http://circle.library.ubc.ca/bitstream/2429/1570/1/ubc_1993_fall_yiman_jiang.pdf"],"dc:language":["eng"],"dc:publisher":["University of British Columbia"],"dc:rights":["For non-commercial purposes only, such as research, private study and education. 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