{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/19388"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/19388","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"A theoretical study of problems in classical nova evolution","abstract":"Three distinct issues in classical nova evolution are addressed with the aid of one- and two-dimensional numerical hydrodynamics.","abstract_html":"Three distinct issues in classical nova evolution are addressed with the aid of one- and two-dimensional numerical hydrodynamics.","abstract_has_math":false,"creators":["Shankar, Anurag"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Astronomy","degree_department":null,"school":null,"contributors":["Truran, James W."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T12:06:00Z","date_published":"2011-05-07T12:06:00Z","updated_at":"2026-07-22T22:25:12Z","subjects":["Physics, Astronomy and Astrophysics"],"languages":["eng"],"rights":["Copyright 1990 Shankar, Anurag"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9026319","(UMI)AAI9026319"],"render_values":[{"text":"AAI9026319","href":null,"code":true},{"text":"(UMI)AAI9026319","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/19388","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Truran, James W."]},{"key":"dc:creator","label":"Author","values":["Shankar, Anurag"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T12:06:00Z","10000-01-01","1990"]},{"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":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1990 Shankar, Anurag"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9026319","(UMI)AAI9026319","http://hdl.handle.net/2142/19388"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Three distinct issues in classical nova evolution are addressed with the aid of one- and two-dimensional numerical hydrodynamics.","The effects of convection on nova outbursts are examined first within the confines of the mixing length theory. It is found that increasing the efficiency of convection enhances the violence of the thermonuclear runaway (TNR). This also relates to the question of the feasibility of obtaining nova outbursts on magnetic white dwarfs among the AM Her systems. In particular, the thesis explores the effects of a strong magnetic field on the TNR. The field interferes with the development of convection during the TNR, which results in lower ejection velocities. However, for field strengths typical of cataclysmic variables, the violence of strong outbursts is affected only moderately.","\"The second question concerns the conditions necessary for the production of strong TNRs in the \"\"hibernation\"\" model of cataclysmic binary evolution, which accounts for non-steady mass transfer. The thesis investigates the feasibility of obtaining strong nova outbursts when the accretion rate during hibernation is decreased by a factor of 100. It is found that such a reduction, for periods of longer than a couple thousand years, is sufficient to ensure violent outbursts, even in the presence of large pre-outburst accretion rates.\"","The final section of the thesis deals with the effects of a common envelope phase (CEP) on the outburst. The motion of the secondary through an expanding common envelope is resisted by frictional drag. This dissipates both energy and angular momentum from the orbit, which get deposited in the envelope, inducing hydrodynamic motion. Significant departures are found to occur in the manner in which mass is lost when the effects of drag are taken into account. Specifically, a CEP is found to accelerate and enhance mass loss. Ejection is found to be concentrated in the orbital plane, with velocities of a few thousand km $s\\sp{-1}$. Possible explanation for observed morphologies of the ejected shells of slow novae may be provided by a CEP. In addition, accelerated mass loss may naturally account for rapid emergence of X-rays and a nebular phase in a number of systems.","Made available in DSpace on 2011-05-07T12:06:00Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9026319.pdf: 5083356 bytes, checksum: c8e508632961920acc8d827f3df48e98 (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:36:37Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:14:51-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["A theoretical study of problems in classical nova evolution"]}]}],"canonical_facts":{"dc:contributor":["Truran, James W."],"dc:creator":["Shankar, Anurag"],"dc:date":["2011-05-07T12:06:00Z","10000-01-01","1990"],"dc:description":["Three distinct issues in classical nova evolution are addressed with the aid of one- and two-dimensional numerical hydrodynamics.","The effects of convection on nova outbursts are examined first within the confines of the mixing length theory. It is found that increasing the efficiency of convection enhances the violence of the thermonuclear runaway (TNR). This also relates to the question of the feasibility of obtaining nova outbursts on magnetic white dwarfs among the AM Her systems. In particular, the thesis explores the effects of a strong magnetic field on the TNR. The field interferes with the development of convection during the TNR, which results in lower ejection velocities. However, for field strengths typical of cataclysmic variables, the violence of strong outbursts is affected only moderately.","\"The second question concerns the conditions necessary for the production of strong TNRs in the \"\"hibernation\"\" model of cataclysmic binary evolution, which accounts for non-steady mass transfer. The thesis investigates the feasibility of obtaining strong nova outbursts when the accretion rate during hibernation is decreased by a factor of 100. It is found that such a reduction, for periods of longer than a couple thousand years, is sufficient to ensure violent outbursts, even in the presence of large pre-outburst accretion rates.\"","The final section of the thesis deals with the effects of a common envelope phase (CEP) on the outburst. The motion of the secondary through an expanding common envelope is resisted by frictional drag. This dissipates both energy and angular momentum from the orbit, which get deposited in the envelope, inducing hydrodynamic motion. Significant departures are found to occur in the manner in which mass is lost when the effects of drag are taken into account. Specifically, a CEP is found to accelerate and enhance mass loss. Ejection is found to be concentrated in the orbital plane, with velocities of a few thousand km $s\\sp{-1}$. Possible explanation for observed morphologies of the ejected shells of slow novae may be provided by a CEP. In addition, accelerated mass loss may naturally account for rapid emergence of X-rays and a nebular phase in a number of systems.","Made available in DSpace on 2011-05-07T12:06:00Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9026319.pdf: 5083356 bytes, checksum: c8e508632961920acc8d827f3df48e98 (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:36:37Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:14:51-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI9026319","(UMI)AAI9026319","http://hdl.handle.net/2142/19388"],"dc:language":["eng"],"dc:rights":["Copyright 1990 Shankar, Anurag"],"dc:subject":["Physics, Astronomy and Astrophysics"],"dc:title":["A theoretical study of problems in classical nova evolution"],"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":"2026-07-22T22:25:12Z"}