Beeck, Benjamin

[["dc.bibliographiccitation.firstpage","48"],["dc.bibliographiccitation.issue","1-2"],["dc.bibliographiccitation.journal","Astronomische Nachrichten"],["dc.bibliographiccitation.lastpage","52"],["dc.bibliographiccitation.volume","334"],["dc.contributor.author","Morin, Julien"],["dc.contributor.author","Jardine, M."],["dc.contributor.author","Reiners, Ansgar"],["dc.contributor.author","Shulyak, D."],["dc.contributor.author","Beeck, Benjamin"],["dc.contributor.author","Hallinan, G."],["dc.contributor.author","Hebb, L."],["dc.contributor.author","Hussain, G. A. J."],["dc.contributor.author","Jeffers, Sandra V."],["dc.contributor.author","Kochukhov, Oleg"],["dc.contributor.author","Vidotto, A."],["dc.contributor.author","Walkowicz, Lucianne M."],["dc.date.accessioned","2018-11-07T09:28:17Z"],["dc.date.available","2018-11-07T09:28:17Z"],["dc.date.issued","2013"],["dc.description.abstract","Magnetic fields are regarded as a crucial element for our understanding of stellar physics. They can be studied with a variety of methods which provide complementary - and sometimes contradictory - information about the structure, strength and dynamics of the magnetic field and its role in the evolution of stars. Stellar magnetic fields can be investigated either with direct methods based on the Zeeman effect or through the observation of activity phenomena resulting from the interaction of the field with the stellar atmosphere. In this Cool Stars 17 Splinter Session we discussed the results obtained by the many ongoing studies of stellar activity and direct studies of surface magnetic fields, as well as the state-of-the-art techniques on which they are based. We show the strengths and limitations of the various approaches currently used and point out their evolution as well as the interest of coupling various magnetism and activity proxies. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim"],["dc.description.sponsorship","Alexander von Humboldt foundation"],["dc.identifier.doi","10.1002/asna.201211771"],["dc.identifier.isi","000325859900012"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/30735"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-v C H Verlag Gmbh"],["dc.relation.issn","1521-3994"],["dc.relation.issn","0004-6337"],["dc.title","Multiple views of magnetism in cool stars"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","97"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","The Astrophysical Journal"],["dc.bibliographiccitation.volume","839"],["dc.contributor.author","Andretta, Vincenzo"],["dc.contributor.author","Giampapa, Mark S."],["dc.contributor.author","Covino, Elvira"],["dc.contributor.author","Reiners, Ansgar"],["dc.contributor.author","Beeck, Benjamin"],["dc.date.accessioned","2018-11-07T10:24:53Z"],["dc.date.available","2018-11-07T10:24:53Z"],["dc.date.issued","2017"],["dc.description.abstract","Simultaneous, high-quality measurements of the neutral helium triplet features at 5876 angstrom and 10830 angstrom in a sample of solar-type stars are presented. The observations were made with ESO telescopes at the La Silla Paranal Observatory under program ID 088.D-0028(A) and MPG Utility Run for Fiber Extended-range Optical Spectrograph 088.A-9029(A). The equivalent widths of these features combined with chromospheric models are utilized to infer the fractional area coverage, or filling factor, of magnetic regions outside of spots. We find that the majority of the sample is characterized by filling factors less than unity. However, discrepancies occur among the coolest K-type and the warmest and most rapidly rotating F-type dwarf stars. We discuss these apparently anomalous results and find that in the case of K-type stars, they are an artifact of the application of chromospheric models best suited to the Sun than to stars with significantly lower T-eff. The case of the F-type rapid rotators can be explained by the measurement uncertainties of the equivalent widths, but they may also be due to a non-magnetic heating component in their atmospheres. With the exceptions noted above, preliminary results suggest that the average heating rates in the active regions are the same from one star to the other, differing in the spatially integrated, observed level of activity due to the area coverage. Hence, differences in activity in this sample are mainly due to the filling factor of active regions."],["dc.description.sponsorship","ESO Telescopes at the La Silla Paranal Observatory [088.D-0028(A)]"],["dc.identifier.doi","10.3847/1538-4357/aa6a14"],["dc.identifier.isi","000399876200006"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/42743"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.publisher","Iop Publishing Ltd"],["dc.relation.issn","1538-4357"],["dc.relation.issn","0004-637X"],["dc.title","Estimates of Active Region Area Coverage through Simultaneous Measurements of the HeI lambda lambda 5876 and 10830 Lines"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]