Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

This dissertation uses radio observations with the Karl G. Jansky Very Large Array (VLA) to investigate the mechanisms that power and shape accreting white dwarfs (WD) and their ejecta. We test the predictions of both simple spherical and steady-state radio emission models by examining nova V1723 Aql, nova V5589 Sgr, symbiotic CH Cyg, and two small surveys of symbiotic binaries. First, we highlight classical nova V1723 Aql with three years of radio observations alongside optical and X-ray observations. We use these observations to show that multiple outflows from the system collided to create early non-thermal shocks with a brightness temperature of ⪆10⁶ K. While the late-time radio light curve is roughly consistent an expanding thermal shell of mass 2x10⁻⁴ M ⊙ solar masses, resolved images of V1723 Aql show elongated material that apparently rotates its major axis over the course of 15 months, much like what is seen in gamma-ray producing nova V959 Mon, suggesting similar structures in the two systems. Next, we examine nova V5589 Sgr, where we find that the early radio emission is dominated by a shock-powered non-thermal flare that produces strong (kTₓ > 33 keV) X-rays. We additionally find roughly 10⁻⁵ M⊙ solar masses of thermal bremsstrahlung emitting material, all at a distance of ~4 kpc. The similarities in the evolution of both V1723 Aql and V5589 Sgr to that of nova V959 Mon suggest that these systems may all have dense equatorial tori shaping faster flows at their poles. Turning our focus to symbiotic binaries, we first use our radio observations of CH Cyg to link the ejection of a collimated jet to a change of state in the accretion disk. We additionally estimate the amount of mass ejected during this period (10⁻⁷ M⊙ masses), and improve measurements of the period of jet precession (P=12013 +/- 74 days). We then use our survey of eleven accretion-driven symbiotic systems to determine that the radio brightness of a symbiotic system could potentially be used as an indicator of whether a symbiotic is powered predominantly by shell burning on the surface of the WD or by accretion. We additionally make the first ever radio detections of seven of the targets in our survey. Our survey of seventeen radio bright symbiotics, comparing observations before and after the upgrades to the VLA, shows the technological feasibility to resolve the nebulae of nearby symbiotic binaries, opening the door for new lines of research. We spatially resolve extended structure in several symbiotic systems in radio for the first time. Additionally, our observations reveal extreme radio variability in symbiotic BF Cyg before and after the production of a jet from the system. Our results from our surveys of symbiotics provide some support for the model of radio emission where the red giant wind is photoionized by the WD, and suggests that there may be a greater population of radio faint, accretion driven symbiotic systems. This work emphasizes the powerful nature of radio observations as a tool for understanding eruptive WD binaries and their outflows.

Com o presente trabalho contribuiu-se para o estudo das composições químicas das estrelas simbióticas do hemisfério sul, muito pouco exploradas na literatura. Apresenta-se um conjunto completo de simbióticas amarelas austrais extraído do catálogo de Belczynski [Belczynski]. Alguns dos objetos analisados não possuem nem sequer dados espectroscópicos na literatura. Obtém-se os dados deste trabalho com o telescópio de 1.6 m do LNA e da base de dados do satélite I.U.E. Calcula-se o avermelhamento a partir das linhas de recombinação do H, aplicando os valores de extinção interestelar obtidos dos espectros no visível aos do U.V. A partir das razões entre as linhas do [OIII] e [NII] e supondo uma temperatura eletrônica de 12 000 K (Nussbaumer [NussbuamerNP]) encontra-se as densidade eletrônicas presentes nas nebulosas dos sistemas simbióticos. Com estes dados, mais os os fluxos das linhas derivam-se as abundâncias químicas das nebulosas dos sistemas simbióticos; C, N, O no U.V. e He, Ar, S, O e N no visível. Comparam-se as abundâncias no visível com as das simbióticas na direção do bojo (Luna [Luna]) e com nebulosas planetárias (Escudero [Escudero]). Nota-se que em geral as simbióticas são mais enriquecidas em N e He do que as planetárias isto ocorre provavelmente porque as progenitoras das estrelas simbióticas são mais massivas do que a das planetárias. No entanto, para elementos como O, Ar e S encontram-se abundâncias muito próximas entre simbióticas e planetárias. Comparam-se também, as abundâncias das simbióticas amarelas desta amostra com a de planetárias do disco extraídas do trabalho de Pottasch [Pottasch84] , cefeidas de Luck e Lambert [Luck], abundâncias das gigantes G,K e M obtidas a partir de Lambert e Ries[Lambert], as anãs G e K de Reddy et al [Reddy], as gigantes M de Smith e Lambert[Smith90], abundâncias das estrelas Ba extraídas de Smith [Smith84], as estrelas mild Ba dos tipos espectrais G8 a K3 de Berdyugina [Berdyugina] , as early R de Dominy [Dominy], estrelas C de Lambert et al [Lambert86] e por fim as estrelas M e S (MS) de Smith & Lambert [Smith90]. Pode-se distinguir dois grupos de simbióticas amarelas a partir dos diagramas C/N-O/N. Um grupo apresenta produtos do ciclo CN e situa-se próximo à curva de baixa metalicidade e metalicidade solar. O outro grupo, encontra-se próximo da curva C/O=1, que consiste de objetos enriquecidos em carbono (Schmid & Nussbaumer[Nussbaumer01]). As estrelas simbióticas amarelas enriquecidas em C não estão univocamente associadas as estrelas Ba ou early R. Estes dois grupos representam as simbióticas amarelas tipo s e d' respectivamente. Por fim, conclui-se que os sistemas simbióticos amarelos analisados neste trabalho confirmam o modelo de que seriam estrelas AGBs iluminadas por alguma fonte quente de radiação. / The present work is a contribution to the study of chemical composition of southern symbiotic stars, scarcely studied in literature. We present a complete set of yellow southern symbiotic stars extracted from Belczynski. Some of the objects analyzed had no spectroscopic data in literature. The data were obtained using 1.6m telescope in LNA, Brazil and the IUE satelite database. The reddening was calculated from Hydrogen recombination lines. From the ratio fluxes of the lines of [OIII] and [NII] and a hypothetical electronic temperature of 12 000K (Nussbaumer) we estimated the eletronic density of the nebulae present in the symbiotic system. With this data plus the fluxes of lines observed we obtained the chemical abundances in symbiotic nebulae; C,N,O in U.V. and He, Ar, S, O and N in visible. The abundances of the yellow symbiotic stars were compared to planetary disc nebulae extracted from Pottasch, cefeids form Luck & Lambert, G, K and M giant abundances from Lambert & Ries, G and K dwarfs from Reddy et. al., M giants from Smith & Lambert, Ba star abundances from Smith, mild Ba stars type G8 and K3 from Berdygina, early R from Dominy, C stars form Lambert et. al. and M and S (MS)stars from Smith & Lambert. We can distinguish two types of yellow symbiotic groups. One group presents CN cycle products and is situated near the low metalicity and solar metalicity curve. The other group is found near the C/O=1 curve that is made of rich carbon objects (Schmid & Nussbaumer).The yellow symbiotic stars enriched in carbon are not univically asociated with Ba or early R stars. These two groups represent respectively the yellow s and d' symbiotics. The yellow symbiotic stars analyzed in this work confirm the model in which they would be AGB stars iluminated by some hot source radiation.

Com o presente trabalho contribuiu-se para o estudo das composições químicas das estrelas simbióticas do hemisfério sul, muito pouco exploradas na literatura. Apresenta-se um conjunto completo de simbióticas amarelas austrais extraído do catálogo de Belczynski [Belczynski]. Alguns dos objetos analisados não possuem nem sequer dados espectroscópicos na literatura. Obtém-se os dados deste trabalho com o telescópio de 1.6 m do LNA e da base de dados do satélite I.U.E. Calcula-se o avermelhamento a partir das linhas de recombinação do H, aplicando os valores de extinção interestelar obtidos dos espectros no visível aos do U.V. A partir das razões entre as linhas do [OIII] e [NII] e supondo uma temperatura eletrônica de 12 000 K (Nussbaumer [NussbuamerNP]) encontra-se as densidade eletrônicas presentes nas nebulosas dos sistemas simbióticos. Com estes dados, mais os os fluxos das linhas derivam-se as abundâncias químicas das nebulosas dos sistemas simbióticos; C, N, O no U.V. e He, Ar, S, O e N no visível. Comparam-se as abundâncias no visível com as das simbióticas na direção do bojo (Luna [Luna]) e com nebulosas planetárias (Escudero [Escudero]). Nota-se que em geral as simbióticas são mais enriquecidas em N e He do que as planetárias isto ocorre provavelmente porque as progenitoras das estrelas simbióticas são mais massivas do que a das planetárias. No entanto, para elementos como O, Ar e S encontram-se abundâncias muito próximas entre simbióticas e planetárias. Comparam-se também, as abundâncias das simbióticas amarelas desta amostra com a de planetárias do disco extraídas do trabalho de Pottasch [Pottasch84] , cefeidas de Luck e Lambert [Luck], abundâncias das gigantes G,K e M obtidas a partir de Lambert e Ries[Lambert], as anãs G e K de Reddy et al [Reddy], as gigantes M de Smith e Lambert[Smith90], abundâncias das estrelas Ba extraídas de Smith [Smith84], as estrelas mild Ba dos tipos espectrais G8 a K3 de Berdyugina [Berdyugina] , as early R de Dominy [Dominy], estrelas C de Lambert et al [Lambert86] e por fim as estrelas M e S (MS) de Smith & Lambert [Smith90]. Pode-se distinguir dois grupos de simbióticas amarelas a partir dos diagramas C/N-O/N. Um grupo apresenta produtos do ciclo CN e situa-se próximo à curva de baixa metalicidade e metalicidade solar. O outro grupo, encontra-se próximo da curva C/O=1, que consiste de objetos enriquecidos em carbono (Schmid & Nussbaumer[Nussbaumer01]). As estrelas simbióticas amarelas enriquecidas em C não estão univocamente associadas as estrelas Ba ou early R. Estes dois grupos representam as simbióticas amarelas tipo s e d' respectivamente. Por fim, conclui-se que os sistemas simbióticos amarelos analisados neste trabalho confirmam o modelo de que seriam estrelas AGBs iluminadas por alguma fonte quente de radiação. / The present work is a contribution to the study of chemical composition of southern symbiotic stars, scarcely studied in literature. We present a complete set of yellow southern symbiotic stars extracted from Belczynski. Some of the objects analyzed had no spectroscopic data in literature. The data were obtained using 1.6m telescope in LNA, Brazil and the IUE satelite database. The reddening was calculated from Hydrogen recombination lines. From the ratio fluxes of the lines of [OIII] and [NII] and a hypothetical electronic temperature of 12 000K (Nussbaumer) we estimated the eletronic density of the nebulae present in the symbiotic system. With this data plus the fluxes of lines observed we obtained the chemical abundances in symbiotic nebulae; C,N,O in U.V. and He, Ar, S, O and N in visible. The abundances of the yellow symbiotic stars were compared to planetary disc nebulae extracted from Pottasch, cefeids form Luck & Lambert, G, K and M giant abundances from Lambert & Ries, G and K dwarfs from Reddy et. al., M giants from Smith & Lambert, Ba star abundances from Smith, mild Ba stars type G8 and K3 from Berdygina, early R from Dominy, C stars form Lambert et. al. and M and S (MS)stars from Smith & Lambert. We can distinguish two types of yellow symbiotic groups. One group presents CN cycle products and is situated near the low metalicity and solar metalicity curve. The other group is found near the C/O=1 curve that is made of rich carbon objects (Schmid & Nussbaumer).The yellow symbiotic stars enriched in carbon are not univically asociated with Ba or early R stars. These two groups represent respectively the yellow s and d' symbiotics. The yellow symbiotic stars analyzed in this work confirm the model in which they would be AGB stars iluminated by some hot source radiation.

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