Дисертації з теми "Binary stellar evolution"
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Pols, Onno Rudolf. "On the evolution of massive close binary stars in stellar populations." Amsterdam : Amsterdam : Sterrenkundig Instituut 'Anton Pannekoek' ; Universiteit van Amsterdam [Host], 1993. http://dare.uva.nl/document/91990.
Повний текст джерелаBarrett, James William. "Topics in astrostatistics : stellar binary evolution, gravitational-wave source modelling and stochastic processes." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8203/.
Повний текст джерелаSaffer, R. A., and J. Liebert. "Search for Close Binary Evolved Stars." Steward Observatory, The University of Arizona (Tucson, Arizona), 1988. http://hdl.handle.net/10150/623897.
Повний текст джерелаOhlmann, Sebastian Thomas [Verfasser], and Friedrich [Akademischer Betreuer] Röpke. "Hydrodynamics of the Common Envelope Phase in Binary Stellar Evolution / Sebastian Thomas Ohlmann ; Betreuer: Friedrich Röpke." Heidelberg : Universitätsbibliothek Heidelberg, 2016. http://d-nb.info/1180615891/34.
Повний текст джерелаOhlmann, Sebastian T. [Verfasser], and Friedrich [Akademischer Betreuer] Röpke. "Hydrodynamics of the Common Envelope Phase in Binary Stellar Evolution / Sebastian Thomas Ohlmann ; Betreuer: Friedrich Röpke." Heidelberg : Universitätsbibliothek Heidelberg, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:16-heidok-215131.
Повний текст джерелаMoran, Chris. "Using observations of detached double degenerate binaries to test theories of stellar evolution in close binary systems." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310751.
Повний текст джерелаDouchin, Dimitri. "Estimation de la fraction binaire de nébuleuses planétaires." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20069/document.
Повний текст джерелаPlanetary nebulae (PNe) are the products of the evolution of intermediate mass stars that have expanded spherically at the end of their lives. Observationally, it has been estimated that 80% of them have non-spherical shapes. Such a high fraction is puzzling and has occupied the PN community for more than 30 years. One scenario that would allow to justify the observed shapes is that a comparable fraction of the progenitors of central stars of PN (CSPN) are not single, but possess a companion. The shape of the nebulae would then be the result of an interaction with this companion. The high fraction of non-spherical PNe would thus imply a high fraction of binary CSPN, making binarity a preferred channel for PN formation. After presenting the current state of knowledge regarding PN formation and shaping and reviewing the diverse efforts to find binaries in PNe, I present my work to detect a near-infrared excess that would be the signature of the presence of cool companions. The first part of the project consists in the analysis of data and photometry acquired and conducted by myself. The second part details an attempt to make use of archived datasets: the Sloan Digital Sky Survey Data Release 7 optical survey and the extended database assembled by Frew (2008). I also present results from a radial velocity analysis of VLT/UVES spectra for 14 objects aiming to the detection of spectroscopic companions. Finally I give details of the analysis of optical photometry data from our observations associated to the detection of companions around CSPN using the photometric variability technique. The main result of this thesis is from the near-infrared excess studies which I combine with previously-published data. I conclude that the if the detected red and NIR flux excess is indicative of a stellar companion then the binary fraction is larger than what we may expect based on the main-sequence progenitor population binary fraction and therefore conclude that binarity is a preferential channel for the formation of PN. I finish by underlining the need for a sample size of ∼ 150 objects to decrease the uncertainty on the PN population binary fraction and increase the statistical significance of this result
Deschamps, Romain. "Evolution of low and intermediate mass stars in binary systems: a new look at Algol systems." Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209077.
Повний текст джерелаstill rather poorly understood. We know that they are composed by a generally B-A main sequence
star and a lighter but more evolved companion star. This paradox is explained by the transfer of mass
between the two stars, but new problems arose. In particular, I studied the mass-transfer driven spin-
up of the accreting star that drives the star to critical rotation and the puzzling, indirectly observed, non-conservative evolution.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Santos, Leonardo Augusto Gonçalves dos. "The rotational evolution of Sun-like stars and the influence of low-mass binary companions." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/14/14131/tde-22052018-174015/.
Повний текст джерелаO programa The Solar Twin Planet Search é um esforço sem precedentes na procura de planetas extra-solares em mais de 70 estrelas extremamente similares ao Sol. Ao longo desse programa, centenas de espectros ópticos de alta qualidade foram obtidos com o espectrógrafo HARPS, que está instalado no telescópio de 3,6 m do Observatório de La Silla. Além da busca de exoplanetas, estes dados são úteis para estudar as propriedades físicas de estrelas como o Sol. Estamos interessados em verificar se o Sol possui uma rotação regular para sua idade quando comparado com estrelas estritamente similares a ele, como que a rotação de gêmeas solares evolui com o tempo e se a rotação dessas estrelas é influenciada pela presença de companheiras estelares. Conclusões anteriores na regularidade da rotação solar são conflitantes, e esta é a primeira vez que uma amostra grande de gêmeas solares com dados espectroscópicos de alta qualidade é usada para esclarecer essa questão. Nossos resultados sugerem que o Sol de fato rota regularmente para sua idade, o que favorece o uso da rotação solar para calibrar a girocronologia -- a estimativa de idades estelares a partir de sua rotação. No entanto, tais resultados também implicam em um processo de evolução rotacional que satura depois da idade solar, constituindo um desvio da amplamente usada relação de Skumanich e apresentando um desafio para a girocronologia. Nós identificamos 18 sistemas binários na amostra de gêmeas solares, das quais apenas três mostram rotações elevadas para suas idades. Os parâmetros orbitais das binárias foram estimados a partir da variação de suas velocidades radiais, e os resultados mostram que suas companheiras espectroscópicas possuem períodos orbitais variando de alguns poucos até muitos anos. Concluimos que a presença de companheiras do tipo anãs vermelhas ou marrons em períodos orbitais moderados não influenciam a evolução rotacional desses sistemas. As peculiaridades de HIP 19911, HIP 67620 e HIP 103983 podem ser completamente explicadas por contaminação espectral de suas companheiras.
Karakas, Amanda I. (Amanda Irene) 1974. "Asymptotic giant branch stars : their influence on binary systems and the interstellar medium." Monash University, School of Mathematical Sciences, 2003. http://arrow.monash.edu.au/hdl/1959.1/5570.
Повний текст джерелаJasniewicz, Gérard. "Sur quelques aspects de la binarite dans les populations stellaires." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13046.
Повний текст джерелаDay-Jones, A. C. "Searching for brown dwarf companions." Thesis, University of Hertfordshire, 2009. http://hdl.handle.net/2299/3475.
Повний текст джерелаMentz, Jacobus Johannes. "A search for pulsating B-type variable stars in the southern open clusters NGC 6204 and Hogg 22 / Jacobus Johannes (Jaco) Mentz." Thesis, North-West University, 2013. http://hdl.handle.net/10394/9520.
Повний текст джерелаThesis (MSc (Space Physics))--North-West University, Potchefstroom Campus, 2013
Passy, Jean-Claude. "Modeling close stellar interactions using numerical and analytical techniques." Thesis, 2013. http://hdl.handle.net/1828/4477.
Повний текст джерелаGraduate
For, Bi-Qing. "Probing stellar evolution through spectroscopy of horizontal branch stars." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-08-3759.
Повний текст джерелаtext
Themeẞl, Nathalie. "Asteroseismic inferences from red-giant stars." Doctoral thesis, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E5F1-E.
Повний текст джерелаWiktorowicz, Grzegorz. "X-Ray Binaries and Ultraluminous X-Ray Sources." Doctoral thesis, 2016.
Знайти повний текст джерелаSaker, Leila Yamila. "Material circunestelar en estrellas de tipo enanas blancas." Doctoral thesis, 2020. http://hdl.handle.net/11086/23533.
Повний текст джерелаSe han descubierto discos de gas en un grupo de enanas blancas con discos de polvo, a través de la detección en sus espectros de lineas de emisión inusuales del triplete de Ca II en 8600 Å. En este contexto, se han obtenido espectros ópticos GMOS/GEMINI para 13 enanas blancas con excesos IR, seleccionados de nuestra muestra de 29 estrellas con discos “debris”, con el objetivo de encontrar la contraparte gaseosa a los discos de polvo. Se presenta además un estudio comparativo de las principales propiedades físicas y de parámetros relacionados al disco de polvo de las enanas blancas con y sin discos de gas detectados. Adicionalmente, se aplicó la técnica de “Eclipse Timing Variation” en una muestra de 8 sistemas binarios eclipsantes formados por enana blanca+estrella de secuencia principal con el objetivo de detectar planetas circumbinarios. Para ello, se obtuvieron observaciones propias con los telescopios argentinos localizados en la Estación Astrofísica de Bosque Alegre y el telescopio Jorge Sahade en el Complejo Astronómico El Leoncito. Las curvas de luz obtenidas, fueron complementadas con las disponibles en las bases de datos del “Catalina Sky Survey” y Kepler+K2. Los tiempos de mínimo fueron obtenidos con el código Wilson & Devinney.
Gas disks have been discovered in a group of white dwarfs with dust disks, through the detection in their spectra of unusual emission lines of the triplet of Ca II at 8600 Å. In this context, GMOS/GEMINI optical spectra have been obtained for 13 white dwarfs with IR excesses, selected from our sample of 29 stars with debris disks, with the aim to find the gaseous counterpart to the dusty disks. We also present a comparative study of the main physical properties and parameters related to the dusty disk of white dwarfs with and without gas disks detected. Additionally, the Eclipse Timing Variation technique was applied in a sample of 8 eclipsing binary systems formed by white dwarf + main sequence star, with the aim to detect circumbinary planets. For this, own observations were obtained with the Argentine telescopes located in the Estación Astrofísica de Bosque Alegre and the Jorge Sahade telescope in the Complejo Astronómico El Leoncito. The light curves obtained were complemented with those available in the databases "Catalina Sky Survey" and Kepler+K2. Minimum times were obtained with the Wilson & Devinney code.
Fil: Saker, Leila Yamila. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación; Argentina.
Karczmarek, Paulina. "Wpływ ewolucji w układach podwójnych na własności gwiazd pulsujących na przykładzie cefeid oraz gwiazd typu RR Lutni." Doctoral thesis, 2019. https://depotuw.ceon.pl/handle/item/3529.
Повний текст джерелаThis doctoral dissertation describes how the properties of pulsating stars, exemplified by RR Lyrae stars and classical Cepheids, can be changed as a result of the presence of a companion in a binary system. The study consists of three diverse projects which can be further developed and extended in the future. The first project aims to show that RR Lyrae (RRL) pulsating stars are reliable and precise standard candles that follow the period-brightness-metallicity relation in the nearinfrared. This relation is then used to determine the distance to two galaxies in the Local Group: Carina and Fornax. The results are consistent with the distances existing in the literature, but are of greater precision, at a level of 5%. The reason behind such precision is smaller contribution of systematic and statistical errors. For example, near-infrared observations are less affected by the interstellar extinction than observations in the visible domain. Also, the effect of metallicity on the brightness of RRL stars in the near-infrared is smaller than in the visible regime. These assets make the near-infrared period-brightnessmetallicity relation for RRL stars a valuable tool for determining distances, in particular to nearby galaxies (distance module not larger than about 22 mag) which do not host classical Cepheid. The results agree with the distances determined using other standard candles, such as red clump stars or stars on the tip of the red giant branch, in the course of the Araucaria Project. A significant discrepancy between obtained results and other distance determinations would mean that additional and not yet addressed effects could alter the distance measurements. One of these effects – the presence of a companion in a binary system – will have been discussed in the next chapters of this doctoral dissertation. The next two projects are of theoretical nature and use a binary population synthesis code StarTrack, created by Belczynski et al. (2002, 2008) and constantly developed since. The population synthesis method allows for statistical description of properties of binary systems as well as for the analysis of the interaction between the components on different evolutionary stages. Both projects examine binary systems with at least one star inside the instability strip, but one project focuses on systems that undergo the mass transfer, whereas the other project investigates the systems that are only gravitationally bound, without mass transfer episodes. A study of a synthetic population of binary stars which experience mass transfer episodes leads to the confirmation of the existence of a new class of pulsating stars, so-called BEP (Binary Evolution Pulsator ). The first and so far the only BEP star is OGLE-BLGRRLYR-02792, the object discovered by Soszyński et al. (2010a) and further studied by Pietrzyński et al. (2012) and Smolec et al. (2013). BEP mimics the pulsational pattern of RRL stars but – due to the mass transfer episode that it has experienced – its mass and evolutionary path are utterly different from RRL’s. This project shows that BEPs are expected to populate the instability strip, in the areas of both RRL stars and Cepheids. Moreover, BEPs can be misclassified as RRLs or Cepheids due to the shape of their light curves. The most effective way to detect BEPs is to observe eclipses in their light curves or fluctuations in their radial velocity curves associated with the orbital motion. Unrecognized BEPs should not be abundant and therefore their presence should not alter the distance measurements based on the period-brightness relation for Cepheids and RRL stars. Nevertheless, the interesting properties and evolutionary paths of BEPs encourage to search for more stars belonging to this new class and to continue to study already known candidates. The project reaffirms that the interactions in binary systems are crucial for explaining the observed properties of some binary pulsating stars. A study of binary stars with no mass transfer episodes was performed in order to check whether the components residing in the instability strip – particularly Cepheids – follow the period-luminosity relation undisturbed by the presence of companions, or rather an additional light from the companions systematically shifts the period-luminosity relation. This issue has appeared frequently in the literature and discussed in a qualitative way. Isolated cases of Cepheid in binary systems that lay significantly above the periodluminosity relation are described by Pietrzyński et al. (2010) and Pilecki et al. (2018). The project, which is presented in this doctoral dissertation, for the first time addresses the issue of the excess light of Cepheids’ companions in both qualitative and quantitative way. Three synthetic populations of binary stars with metallicities of Milky Way, Small and Large Magellanic Clouds were used to determine the change in the accuracy of distance determinations calculated from period-luminosity relations for a mixed sample of Cepheids (single and binary stars) at different wavelengths and for different percentage of binary systems in the sample. The results reassure that distance determinations from the periodluminosity relation for a mixed sample are only slightly shifted due to the excess light from the companion, which can be further minimised if the observations are carried out at larger wavelengths. This dissertation consists of three main chapters, presenting the projects described above, the introduction which precedes them and the summary that follows them. The two appendices include: a collection of near-infrared period-luminosity-metallicity relations for RRL stars that are available in the literature and a detailed description of the StarTrackpopulation synthesis code. The introduction is preceded by a list of physical units used in this thesis together with their values expressed in the SI or cgs systems, and by a list of abbreviations used in this thesis together with their long form and the Polish translation. Every non-integer number written in the decimal system has a decimal separator which is a period, and not a comma, as would Polish typographic practise recommend. This convention is widely used in the literature around the world, as well as in all publications cited here. In order to preserve the consistency with the cited publications, a period symbol is used as a decimal separator also in this dissertation. The thesis uses prefixes to a unit of time, for example 5 Gyr or 5 billion years, 28 kyr or 28 thousand years. Both forms are used interchangeably, although only Gyr, kyr forms appear in the figures, whereas the long form dominates in the text. The word ’brightness’ is most often used as a synonym for the ’luminosity’, L. Whenever star’s brightness is expressed a in specific passband, the filter name and the magnitude unit are given. In individual cases, when the brightness and luminosity appear together in the text, there is a clear distinction between the brightness and the luminosity.