Dreizler, Stefan

[["dc.bibliographiccitation.artnumber","012023"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Journal of Physics. Conference Series"],["dc.bibliographiccitation.volume","172"],["dc.contributor.affiliation","R Heller, ; 1Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany"],["dc.contributor.affiliation","R Østensen, ; 3Institute of Astronomy, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium"],["dc.contributor.author","Heller, R."],["dc.contributor.author","Homeier, D."],["dc.contributor.author","Dreizler, S."],["dc.contributor.author","Østensen, R."],["dc.date.accessioned","2019-07-09T11:52:44Z"],["dc.date.available","2019-07-09T11:52:44Z"],["dc.date.issued","2009"],["dc.date.updated","2022-02-19T14:25:24Z"],["dc.description.abstract","We present a catalog of 857 WD (WD)-M star binaries from the sixth data release of the Sloan Digital Sky Survey (SDSS), most of them known before. For 636 of them, we give a spectral analysis and derive the basic parameters of the stellar constituents and their distances from Earth. Our purpose is to test the modeled spectra applied in the fitting procedure on the one hand and to confine the respective evolutionary scenarios on the other hand. We use a χ2 minimization technique in order to decompose each combined spectrum and yield independent parameter estimates for the components. 41 of the stellar duets in our spectroscopic sample are optically resolved on the respective SDSS images. Despite various selection effects, the fraction of 6.4 % of WD-M star binaries with orbital separation around 500 AU and orbital perdiods of ~ 104 yr is a criterion for evolutionary models of stellar binary systems. We find 20 out of 636 WDs being fitted as DOs, with 16 of them indicating TefWD around 40000K. This excess of cool DOs is most likely due to additional WDs in the DB-DO Teff range, for which no detailed fitting was done. Furthermore, we identify 70 very low-mass objects, meaning secondaries with masses smaller than about 0.1 Modot, as candidate substellar companions. A trend of WD masses towards higher values in a binary constellation compared to those of field WDs is compatible with our results."],["dc.identifier.doi","10.1088/1742-6596/172/1/012023"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/5875"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/60260"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1742-6596"],["dc.relation.orgunit","Fakultät für Physik"],["dc.rights","Goescholar"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.subject.ddc","530"],["dc.title","Spectral analysis of 636 WD - M star binaries from the Sloan Digital Sky Survey (Data Release 6)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","012060"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Journal of Physics. Conference Series"],["dc.bibliographiccitation.volume","172"],["dc.contributor.affiliation","S D Hügelmeyer, ; 1Institut für Astrophysik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany"],["dc.contributor.affiliation","S Dreizler, ; 1Institut für Astrophysik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany"],["dc.contributor.affiliation","D Homeier, ; 1Institut für Astrophysik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany"],["dc.contributor.affiliation","P Hauschildt, ; 2Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany"],["dc.contributor.author","Hügelmeyer, S. D."],["dc.contributor.author","Dreizler, S."],["dc.contributor.author","Homeier, D."],["dc.contributor.author","Hauschildt, P."],["dc.date.accessioned","2019-07-09T11:52:44Z"],["dc.date.available","2019-07-09T11:52:44Z"],["dc.date.issued","2009"],["dc.date.updated","2022-02-19T14:40:41Z"],["dc.description.abstract","Gas and dust disks are common objects in the universe and can be found around various objects, e.g. young stars, cataclysmic variables, active galactic nuclei, or white dwarfs. The light that we receive from disks provides us with clues about their composition, temperature, and density. In order to better understand the physical and chemical dynamics of these disks, self-consistent radiative transfer simulations are inevitable. Therefore, we have developed a 1+1D radiative transfer code as an extension to the well-established model atmosphere code PHOENIX. We will show the potential of the application of our code to model the spectra of white dwarf debris disks."],["dc.identifier.doi","10.1088/1742-6596/172/1/012060"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/5874"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/60259"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1742-6596"],["dc.relation.orgunit","Fakultät für Physik"],["dc.rights","Goescholar"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.subject.ddc","530"],["dc.title","Spectral synthesis of circumstellar disks - application to white dwarf debris disks"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]