{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/70662"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/70662","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The Interstellar Medium Along The Life of Sight Toward X Per","abstract":"I have used ultraviolet, optical, and radio observations of the B0 V star X Per to analyze the physical conditions within the obscuring diffuse cloud. The ultraviolet data are from the International Ultraviolet Explorer satellite, the optical data are primarily blue echelle spectra, and the radio data are ('12)CO and ('13)CO J = 1-0 emission lines.","abstract_html":"I have used ultraviolet, optical, and radio observations of the B0 V star X Per to analyze the physical conditions within the obscuring diffuse cloud. The ultraviolet data are from the International Ultraviolet Explorer satellite, the optical data are primarily blue echelle spectra, and the radio data are ('12)CO and ('13)CO J = 1-0 emission lines.","abstract_has_math":false,"creators":["Lien, David Jeffrey"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Astronomy","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-16T00:55:13Z","date_published":"2014-12-16T00:55:13Z","updated_at":"2026-07-22T22:26:03Z","subjects":["Physics, Astronomy and Astrophysics"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8324595"],"render_values":[{"text":"(UMI)AAI8324595","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/70662","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Lien, David Jeffrey"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-16T00:55:13Z","10000-01-01","1983"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Astronomy"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Physics, Astronomy and Astrophysics"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/70662","(UMI)AAI8324595"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["I have used ultraviolet, optical, and radio observations of the B0 V star X Per to analyze the physical conditions within the obscuring diffuse cloud. The ultraviolet data are from the International Ultraviolet Explorer satellite, the optical data are primarily blue echelle spectra, and the radio data are ('12)CO and ('13)CO J = 1-0 emission lines.","I observed more than 200 atomic and molecular UV absorption lines, and detected previously unobserved transitions from SiI, MgI, SI, ClI, FeII, GeII, and GaII. I also detected the O-O band of the F-X electronic system of C(,2). I derived a kinetic temperature of 40 K from a line profile analysis of this system. The electron density is 0.02 cm('-3). The hydrogen density ranges from 100 cm('-3) to 1000 cm('-3), depending on the method used to derive it.","I developed a simple model of this diffuse cloud based on the observed depletions, color excess, and total hydrogen column density. This model assumes the cloud is supported by turbulence. The model accurately predicts the neutral and dominant stage ion column densities, the average electron density, and the column densities of the fine structure lines of CI and CII. The density ranges from 35 cm('-3) at the edge of the cloud to 700 cm('-3) at the center. The mean electron density is 0.04 cm('-3), although the central region has n(,e) = 0.1 cm('-3). The data and the model are consistent with the existence of a velocity parameter gradient within the cloud, the effect of which is to produce the observed composite curve of growth.","Made available in DSpace on 2014-12-16T00:55:13Z (GMT). No. of bitstreams: 1 8324595.pdf: 7441628 bytes, checksum: 88710b9ca97ff8ce2679c724aa3349c4 (MD5) Previous issue date: 1983","Embargo set by: Seth Robbins for item 70828 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","289 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983."]},{"key":"dc:title","label":"Title","values":["The Interstellar Medium Along The Life of Sight Toward X Per"]}]}],"canonical_facts":{"dc:creator":["Lien, David Jeffrey"],"dc:date":["2014-12-16T00:55:13Z","10000-01-01","1983"],"dc:description":["I have used ultraviolet, optical, and radio observations of the B0 V star X Per to analyze the physical conditions within the obscuring diffuse cloud. The ultraviolet data are from the International Ultraviolet Explorer satellite, the optical data are primarily blue echelle spectra, and the radio data are ('12)CO and ('13)CO J = 1-0 emission lines.","I observed more than 200 atomic and molecular UV absorption lines, and detected previously unobserved transitions from SiI, MgI, SI, ClI, FeII, GeII, and GaII. I also detected the O-O band of the F-X electronic system of C(,2). I derived a kinetic temperature of 40 K from a line profile analysis of this system. The electron density is 0.02 cm('-3). The hydrogen density ranges from 100 cm('-3) to 1000 cm('-3), depending on the method used to derive it.","I developed a simple model of this diffuse cloud based on the observed depletions, color excess, and total hydrogen column density. This model assumes the cloud is supported by turbulence. The model accurately predicts the neutral and dominant stage ion column densities, the average electron density, and the column densities of the fine structure lines of CI and CII. The density ranges from 35 cm('-3) at the edge of the cloud to 700 cm('-3) at the center. The mean electron density is 0.04 cm('-3), although the central region has n(,e) = 0.1 cm('-3). The data and the model are consistent with the existence of a velocity parameter gradient within the cloud, the effect of which is to produce the observed composite curve of growth.","Made available in DSpace on 2014-12-16T00:55:13Z (GMT). No. of bitstreams: 1 8324595.pdf: 7441628 bytes, checksum: 88710b9ca97ff8ce2679c724aa3349c4 (MD5) Previous issue date: 1983","Embargo set by: Seth Robbins for item 70828 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","289 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983."],"dc:identifier":["http://hdl.handle.net/2142/70662","(UMI)AAI8324595"],"dc:subject":["Physics, Astronomy and Astrophysics"],"dc:title":["The Interstellar Medium Along The Life of Sight Toward X Per"],"dc:type":["text"],"thesis:degree_discipline":["Astronomy"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:03Z"}