The general objective of the present work is to contribute to the knowledge of the physics of Be Stars. In particular, we are interested in studying and characterizing their pulsational properties. A very suitable tool to reach this goal is the study and analysis of photometric time series with the maximum time baseline, density and photometric accuracy.The space mission COROT scheduled to be launched in December 2006, will provide ultra high precision, relative stellar photometry for very long continuous observing runs. Up to ten stars will be observed in the seismology fields with a photometric accuracy of a few 10-4 and color information during 150 days.The observations of Be stars with COROT will provide photometric time series with unprecedented quality. Their analysis will allow us to qualitatively improve our knowledge and understanding of the pulsational characteristics of Be stars. In consequence, we have started a research project aimed at observing Be stars both in the seismology and exoplanet fields of COROT.In this thesis we present the first step of this project, which is the preparation and study of the sample of Be stars that will be observed by COROT. We have performed photometric analysis of all Be stars located in the seismology fields (Chap. 2). Special emphasis has been given to two stars (NW Ser and V1446 Aql) in which we have detected multiperiodic variability and these variations have been modeled in terms of stellar pulsations (Chap. 3). We have also performed an in-depth spectroscopic study of NW Ser and identified the non-radial pulsating modes taking into account the rotational effects (Chap. 4). A technique to search for faint Be stars based on CCD photometry has been developed and is presented in Chap. 5. We also present a list of faint Be stars located in the exoplanet fields of COROT detected with this technique and which we propose as targets for COROT. In addition, we have proven that our period-analysis techniques are suitable to detect multiperiodicity in large temporal baseline data. In particular, we have detected non-radial pulsations in some Be stars in the low-metallicity galaxy Small Magellanic Clouds (Chap. 6). The current theoretical models do not predict the presence of pulsational instabilities in such low-metallicity environment, and therefore, our results point towards the necessity of new and improved models.
| Identifer | oai:union.ndltd.org:TDX_UV/oai:www.tdx.cat:10803/9886 |
| Date | 15 December 2006 |
| Creators | Gutiérrez Soto, Juan |
| Contributors | Fabregat Llueca, Juan, Universitat de València. Departament de Física Teòrica |
| Publisher | Universitat de València |
| Source Sets | Universitat de València |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:eu-repo/semantics/publishedVersion |
| Format | application/pdf |
| Source | TDX (Tesis Doctorals en Xarxa) |
| Rights | info:eu-repo/semantics/openAccess, ADVERTIMENT. L'accés als continguts d'aquesta tesi doctoral i la seva utilització ha de respectar els drets de la persona autora. Pot ser utilitzada per a consulta o estudi personal, així com en activitats o materials d'investigació i docència en els termes establerts a l'art. 32 del Text Refós de la Llei de Propietat Intel·lectual (RDL 1/1996). Per altres utilitzacions es requereix l'autorització prèvia i expressa de la persona autora. En qualsevol cas, en la utilització dels seus continguts caldrà indicar de forma clara el nom i cognoms de la persona autora i el títol de la tesi doctoral. No s'autoritza la seva reproducció o altres formes d'explotació efectuades amb finalitats de lucre ni la seva comunicació pública des d'un lloc aliè al servei TDX. Tampoc s'autoritza la presentació del seu contingut en una finestra o marc aliè a TDX (framing). Aquesta reserva de drets afecta tant als continguts de la tesi com als seus resums i índexs. |
Page generated in 0.0117 seconds