Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 10 of 10 for “"Wolf-Rayet"”.
-
In search of binary Wolf-Rayet central stars of planetary nebulae
… galactic PNe, 10 to 20 % are known to host a Wolf-Rayet type central star ([WR] CSPN). These [WR] CSPNe are known to be very hydrogen deficient (H-deficient), the mechanism behind which is not clearly understood. A binary central star (CS) or a merger scenario is very likely to be responsible …
-
Analyse hochaufgelöster spektroskopischer Zeitserien der Wolf-Rayet-Doppelsternsysteme [Gamma] 2 Velorum, WR 22 und HD 5980
… umfangreiche spektroskopische Zeitserien dreier Wolf-Rayet-Doppelsternsysteme (gamma2 Velorum, WR 22 und HD 5980) gewonnen werden. Selbst für die langperiodischen Systeme gamma2 Velorum und WR 22 (P sim 80 Tage) gelangen dabei einzigartige Serien über einen kompletten Bahnumlauf mit einer …
-
Celestial Paleontology: The Legacy of Dying Stars
… backbone of life as we know it.</p> <p>High mass Wolf-Rayet stars are likely progenitors of many types of Supernova, yet due to observational constraints we lack the most basic information about most of them: rather they are part of binary systems. This information is key to the determination of …
-
Massive stars in the Galactic Center Quintuplet cluster
… cluster, the spectral analysis of the cluster Wolf-Rayet stars of the nitrogen sequence to determine their fundamental stellar parameters, and discusses the obtained results in a general context. The Quintuplet cluster was discovered in one of the first infrared surveys of the Galactic center …
-
Comprehensive analyses of massive binaries and implications on stellar evolution
… binaries, high mass X-ray binaries (HMXBs), and Wolf-Rayet (WR) binaries, were investigated by means of spectral, orbital, and evolutionary analyses. The spectral analyses were performed with the non-local thermodynamic equillibrium (non-LTE) Potsdam Wolf-Rayet (PoWR) model atmosphere code. …
-
A New Era of Observational Capability at Ritter Observatory: Spectropolarimetry from Exoplanets to Circumstellar Disks and Beyond
… were initially focused on a selection of Be and Wolf-Rayet stars, we sought to investigate potential polarimetric variability in exoplanet systems. In particular we focused on the system HD189733, as there was previous observational work in the literature claiming both a detection and …
-
The formation and evolution of massive clusters in extragalactic environments
… of clusters at young ages. The presence of Wolf-Rayet stars was also investigated within the clusters and the unreliability of Hα photometry in young cluster age and mass fitting was explored. Secondly, the cluster population of NGC 1566 was used to investigate the cluster mass function and …
-
Study of supernovae and massive stars and prospects with the 4m International Liquid Mirror Telescope
… (e.g. supergiant, luminous blue variable and Wolf-Rayet). They strongly influence their environments through their energetic ionization radiation and powerful stellar winds. Furthermore, the formation of low- and intermediate-mass stars are also being regulated by them. The Carina nebula …
-
Hydrogen-deficient central stars of planetary nebulae
… a strong stellar wind, similar to massive Pop-I Wolf-Rayet stars, and are in analogy classified as [WC]. The brackets distinguish the special type from the massive WC stars. Qualitative spectral analyses of [WC] stars lead to the assumption of an evolutionary sequence from the cooler, so-called …