Schuh, Sonja

[["dc.bibliographiccitation.firstpage","457"],["dc.bibliographiccitation.issue","3-4"],["dc.bibliographiccitation.journal","Astrophysics and Space Science"],["dc.bibliographiccitation.lastpage","464"],["dc.bibliographiccitation.volume","291"],["dc.contributor.author","O'Toole, S. J."],["dc.contributor.author","Falter, S."],["dc.contributor.author","Heber, Ulrich"],["dc.contributor.author","Jeffery, C. S."],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Schuh, S. L."],["dc.date.accessioned","2018-11-07T10:52:04Z"],["dc.date.available","2018-11-07T10:52:04Z"],["dc.date.issued","2004"],["dc.description.abstract","We present the first results from the MultiSite Spectroscopic Telescope (MSST) observations of the sdBV star PG 1605+072. Pulsating sdB stars (also known as EC 14026 stars) offer the chance to gain new insights into the formation and evolution of extreme Horizontal Branch stars using the tools of asteroseismology. PG1605+072 is an outstanding object in its class, with the richest frequency spectrum, the longest periods, and the largest variations. The MSST campaign took place in May/June 2002 immediately following the Whole Earth Telescope Xcov22 run, which observed PG 1605+072 as an alternate target. We will first give an overview of the project and its feasibility, after which we will present the massive data set, made up of 399 h of photometry and 151 h of spectroscopy. The overall aims of the project are to examine light/velocity amplitude ratios and phase differences, changes in equivalent width/line index, and lambda-dependence of photometric amplitudes, and to use these properties for mode identification."],["dc.identifier.doi","10.1023/B:ASTR.0000044360.79737.38"],["dc.identifier.isi","000224389400041"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/49036"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Kluwer Academic Publ"],["dc.publisher.place","Dordrecht"],["dc.relation.conference","Meeting on sdB Stars"],["dc.relation.eventlocation","Keele Univ, Staffordshire, ENGLAND"],["dc.relation.issn","0004-640X"],["dc.title","MSST observations of the pulsating sdB star PG 1605+072"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","231"],["dc.bibliographiccitation.issue","1-2"],["dc.bibliographiccitation.journal","Astrophysics and Space Science"],["dc.bibliographiccitation.lastpage","242"],["dc.bibliographiccitation.volume","329"],["dc.contributor.author","Schuh, Sonja"],["dc.contributor.author","Silvotti, Roberto"],["dc.contributor.author","Lutz, Ronny"],["dc.contributor.author","Loeptien, Bjoern"],["dc.contributor.author","Green, Elizabeth M."],["dc.contributor.author","Ostensen, Roy H."],["dc.contributor.author","Leccia, Silvio"],["dc.contributor.author","Kim, Seung-Lee"],["dc.contributor.author","Fontaine, Gilles"],["dc.contributor.author","Charpinet, Stephane"],["dc.contributor.author","Francoeur, Myriam"],["dc.contributor.author","Randall, Suzanna"],["dc.contributor.author","Rodriguez-Lopez, Cristina"],["dc.contributor.author","van Grootel, Valerie"],["dc.contributor.author","Odell, Andrew P."],["dc.contributor.author","Paparo, Margit"],["dc.contributor.author","Bognar, Zsofia"],["dc.contributor.author","Papics, Peter"],["dc.contributor.author","Nagel, Thorsten"],["dc.contributor.author","Beeck, Benjamin"],["dc.contributor.author","Hundertmark, Markus"],["dc.contributor.author","Stahn, Thorsten"],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Hessman, Frederic V."],["dc.contributor.author","Dall'Ora, Massimo"],["dc.contributor.author","Mancini, Dario"],["dc.contributor.author","Cortecchia, Fausto"],["dc.contributor.author","Benatti, Serena"],["dc.contributor.author","Claudi, Riccardo"],["dc.contributor.author","Janulis, Rimvydas"],["dc.date.accessioned","2018-11-07T08:38:16Z"],["dc.date.available","2018-11-07T08:38:16Z"],["dc.date.issued","2010"],["dc.description.abstract","In 2007, a companion with planetary mass was found around the pulsating subdwarf B star V391 Pegasi with the timing method, indicating that a previously undiscovered population of substellar companions to apparently single subdwarf B stars might exist. Following this serendipitous discovery, the EXOTIME (http://www.na.astro.it/similar to silvotti/exotime/)) monitoring program has been set up to follow the pulsations of a number of selected rapidly pulsating subdwarf B stars on time scales of several years with two immediate observational goals: (1) determine (P)over dot of the pulsational periods P (2) search for signatures of substellar companions in O-C residuals due to periodic light travel time variations, which would be tracking the central star's companion-induced wobble around the centre of mass These sets of data should therefore, at the same time, on the one hand be useful to provide extra constraints for classical asteroseismological exercises from the P. ( comparison with \"local\" evolutionary models), and on the other hand allow one to investigate the preceding evolution of a target in terms of possible \"binary\" evolution by extending the otherwise unsuccessful search for companions to potentially very low masses. While timing pulsations may be an observationally expensive method to search for companions, it samples a different range of orbital parameters, inaccessible through orbital photometric effects or the radial velocity method: the latter favours massive close-in companions, whereas the timing method becomes increasingly more sensitive toward wider separations. In this paper we report on the status of the on-going observations and coherence analysis for two of the currently five targets, revealing very well-behaved pulsational characteristics in HS 0444+0458, while showing HS 0702+6043 to be more complex than previously thought."],["dc.identifier.doi","10.1007/s10509-010-0356-4"],["dc.identifier.isi","000282823200038"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/7631"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/18728"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.relation.issn","0004-640X"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","EXOTIME: searching for planets around pulsating subdwarf B stars"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","L31"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","L34"],["dc.bibliographiccitation.volume","445"],["dc.contributor.author","Schuh, Sonja"],["dc.contributor.author","Huber, Johannes"],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Heber, Ulrich"],["dc.contributor.author","O'Toole, S. J."],["dc.contributor.author","Green, Elizabeth M."],["dc.contributor.author","Fontaine, Gilles"],["dc.date.accessioned","2018-11-07T10:30:18Z"],["dc.date.available","2018-11-07T10:30:18Z"],["dc.date.issued","2006"],["dc.description.abstract","Context. The hot subdwarf B star HS 0702 0702+6043 is known as a large-amplitude, short-period p-mode pulsator of the EC 14026 type. Its atmospheric parameters place it at the common boundary between the empirical instability regions of the EC 14026 variables and the typically C cooler long-period g-mode pulsators of the PG1716 kind. Aims. We analyse and interpret the photometric var variability iability of HS 0702 0702+ 6043 in order to explore its asteroseismological potential. Methods. We report on rapid wide band CCD photometric observations to follow up on and confirm the serendipitous discovery of multiperiodic long- period luminosity variations with typical time scales of similar to 1 h in HS 0702 0702+6043, in addition to the two previously known pulsations at 363 s and 383 s. In particular, we isolate a relatively low-amplitude (similar to 4 mmag), long-period (3538 +/- 130 s) light variation. Results. We argue that the most likely origin for this luminosity variation is the presence of an excited g-mode pulsation. If confirmed, HS 0702 0702+6043 would constitute a rare addition to the very select class of pulsating stars showing sim lect simultaneously parts of their pressure and ultaneously gravity mode pulsation spectra. The asteroseismological potential of such stars is immense, and HS 0702 0702+6043 thus becomes a target of choice for future investigations. While our discovery appears consistent with the location of HS 0702 0702+6043 at the common boundary between the two families of pulsating sdB stars, it does challenge theory's current description of stability and driving mechanisms in pulsating B subdwarfs."],["dc.identifier.doi","10.1051/0004-6361:200500210"],["dc.identifier.fs","45041"],["dc.identifier.isi","000234404500003"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/7680"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43835"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","1432-0746"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","HS 0702+6043: a star showing both short-period p-mode and long-period g-mode oscillations"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","649"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","U9"],["dc.bibliographiccitation.volume","410"],["dc.contributor.author","Schuh, S. L."],["dc.contributor.author","Handler, G."],["dc.contributor.author","Drechsel, H."],["dc.contributor.author","Hauschildt, P. H."],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Medupe, R."],["dc.contributor.author","Karl, C."],["dc.contributor.author","Napiwotzki, R."],["dc.contributor.author","Kim, S. L."],["dc.contributor.author","Park, B. G."],["dc.contributor.author","Wood, M. A."],["dc.contributor.author","Paparo, Margit"],["dc.contributor.author","Szeidl, B."],["dc.contributor.author","Viraghalmy, G."],["dc.contributor.author","Zsuffa, D."],["dc.contributor.author","Hashimoto, O."],["dc.contributor.author","Kinugasa, K."],["dc.contributor.author","Taguchi, H."],["dc.contributor.author","Kambe, E."],["dc.contributor.author","Leibowitz, E. M."],["dc.contributor.author","Ibbetson, P."],["dc.contributor.author","Lipkin, Y."],["dc.contributor.author","Nagel, T."],["dc.contributor.author","Gohler, E."],["dc.contributor.author","Pretorius, M. L."],["dc.date.accessioned","2018-11-07T10:34:54Z"],["dc.date.available","2018-11-07T10:34:54Z"],["dc.date.issued","2003"],["dc.description.abstract","We report the discovery of a new eclipsing system less than one arcminute south of the pulsating DB white dwarf KUV 05134+2605. The object could be identified with the point source 2MASS J0516288+260738 published by the Two Micron All Sky Survey. We present and discuss the first light curves as well as some additional colour and spectral information. The eclipse period of the system is 1.29 d, and, assuming this to be identical to the orbital period, the best light curve solution yields a mass ratio of m(2)/m(1) = 0.11, a radius ratio of r(2)/r(1) approximate to 1 and an inclination of 74degrees. The spectral anaylsis results in a T-eff = 4200 K for the primary. On this basis, we suggest that the new system probably consists of a late K + Brown dwarf (which would imply a system considerably younger than approximate to 0.01 Gyr to have r(2)/r(1) approximate to 1), and outline possible future observations."],["dc.identifier.doi","10.1051/0004-6361:20031241"],["dc.identifier.isi","000185917300027"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/44975"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0004-6361"],["dc.title","2MASS J0516288+260738: Discovery of the first eclipsing late K+ Brown dwarf binary system?"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","321"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","BALTIC ASTRONOMY"],["dc.bibliographiccitation.lastpage","325"],["dc.bibliographiccitation.volume","15"],["dc.contributor.author","Jeffery, C. S."],["dc.contributor.author","Heber, Ulrich"],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","O'Toole, S. J."],["dc.contributor.author","Schuh, S. L."],["dc.contributor.author","Woolf, Vincent M."],["dc.contributor.author","Falter, S."],["dc.contributor.author","Nitta, A."],["dc.contributor.author","Kleinman, S."],["dc.contributor.author","Krzesinski, J."],["dc.contributor.author","Billeres, M."],["dc.date.accessioned","2018-11-07T10:30:35Z"],["dc.date.available","2018-11-07T10:30:35Z"],["dc.date.issued","2006"],["dc.description.abstract","The MultiSite Spectroscopic Telescope (MSST) campaign aimed to provide a detailed view of the short-period pulsating subdwarf B star PC 1605+ 072. We present results from the part of the campaign undertaken on 4 m telescopes in 2002 May and June."],["dc.identifier.isi","000237216400026"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43901"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Inst Theoretical Physics Astronomy"],["dc.publisher.place","Moletai"],["dc.relation.conference","2nd Meeting on Hot Subdwarf Stars and Related Objects"],["dc.relation.eventlocation","Santa Cruz de la Palma, SPAIN"],["dc.relation.issn","1392-0049"],["dc.title","The MSST campaign: 4 m spectroscopy of PG 1605+072"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","667"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","674"],["dc.bibliographiccitation.volume","440"],["dc.contributor.author","O'Toole, S. J."],["dc.contributor.author","Heber, Ulrich"],["dc.contributor.author","Jeffery, C. S."],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Schuh, S. L."],["dc.contributor.author","Woolf, Vincent M."],["dc.contributor.author","Falter, S."],["dc.contributor.author","Green, Elizabeth M."],["dc.contributor.author","For, B. Q."],["dc.contributor.author","Hyde, E. A."],["dc.contributor.author","Kjeldsen, Hans"],["dc.contributor.author","Mauch, T."],["dc.contributor.author","White, B. A."],["dc.date.accessioned","2018-11-07T10:55:55Z"],["dc.date.available","2018-11-07T10:55:55Z"],["dc.date.issued","2005"],["dc.description.abstract","We present results and analysis for the 2m spectroscopic part of the MultiSite Spectroscopic Telescope (MSST) campaign undertaken in May/June 2002. The goal of the project was to observe the pulsating subdwarf B star PG1605+072 simultaneously in velocity and photometry and to resolve as many of the > 50 known modes as possible, which will allow a detailed asteroseismological analysis. We have obtained over 150 h of spectroscopy, leading to an unprecedented noise level of only 207 m s(-1). We report here the detection of 20 frequencies in velocity, with two more likely just below our detection threshold. In particular, we detect 6 linear combinations, making PG1605+072 only the second star known to show such frequencies in velocity. We investigate the phases of these combinations and their parent modes and find relationships between them that cannot be easily understood based on current theory. These observations, when combined with our simultaneous photometry, should allow asteroseismology of this most complicated of sdB pulsators."],["dc.identifier.doi","10.1051/0004-6361:20053352"],["dc.identifier.fs","38258"],["dc.identifier.isi","000231547400033"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9866"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/49894"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0004-6361"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","The MultiSite Spectroscopic Telescope campaign: 2 m spectroscopy of the V361 Hya variable PG1605+072"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1164"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Monthly Notices of the Royal Astronomical Society"],["dc.bibliographiccitation.lastpage","1174"],["dc.bibliographiccitation.volume","348"],["dc.contributor.author","Reed, M. D."],["dc.contributor.author","Kawaler, Steven D."],["dc.contributor.author","Zola, S."],["dc.contributor.author","Jiang, X. J."],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Schuh, S. L."],["dc.contributor.author","Deetjen, J. L."],["dc.contributor.author","Kalytis, R."],["dc.contributor.author","Meistas, E."],["dc.contributor.author","Janulis, Rimvydas"],["dc.contributor.author","Alisauskas, D."],["dc.contributor.author","Krzesinski, J."],["dc.contributor.author","Vuckovic, M."],["dc.contributor.author","Moskalik, P."],["dc.contributor.author","Ogloza, W."],["dc.contributor.author","Baran, A."],["dc.contributor.author","Stachowski, G."],["dc.contributor.author","Kurtz, D. W."],["dc.contributor.author","Perez, JMG"],["dc.contributor.author","Mukadam, A. S."],["dc.contributor.author","Watson, T. K."],["dc.contributor.author","Koen, C."],["dc.contributor.author","Bradley, P. A."],["dc.contributor.author","Cunha, M. S."],["dc.contributor.author","Kilic, M."],["dc.contributor.author","Klumpe, E. W."],["dc.contributor.author","Carlton, R. F."],["dc.contributor.author","Handler, G."],["dc.contributor.author","Kilkenny, D."],["dc.contributor.author","Riddle, R."],["dc.contributor.author","Dolez, N."],["dc.contributor.author","Vauclair, G."],["dc.contributor.author","Chevreton, M."],["dc.contributor.author","Wood, M. A."],["dc.contributor.author","Grauer, A."],["dc.contributor.author","Bromage, G."],["dc.contributor.author","Solheim, J. E."],["dc.contributor.author","Ostensen, Roy H."],["dc.contributor.author","Ulla, A."],["dc.contributor.author","Burleigh, M."],["dc.contributor.author","Good, S."],["dc.contributor.author","Hurkal, O."],["dc.contributor.author","Anderson, R."],["dc.contributor.author","Pakstiene, E."],["dc.date.accessioned","2018-11-07T10:50:20Z"],["dc.date.available","2018-11-07T10:50:20Z"],["dc.date.issued","2004"],["dc.description.abstract","Since pulsating subdwarf B (sdBV or EC14026) stars were first discovered, observational efforts have tried to realize their potential for constraining the interior physics of extreme horizontal branch stars. Difficulties encountered along the way include uncertain mode identifications and a lack of stable pulsation mode properties. Here we report on Feige 48, an sdBV star for which follow- up observations have been obtained spanning more than four years. These observations show some stable pulsation modes. We resolve the temporal spectrum into five stable pulsation periods in the range 340- 380 s with amplitudes less than 1 per cent, and two additional periods that appear in one data set each. The three largest amplitude periodicities are nearly equally spaced, and we explore the consequences of identifying them as a rotationally split l = 1 triplet by consulting a representative stellar model. The general stability of the pulsation amplitudes and phases allows us to use the pulsation phases to constrain the time- scale of evolution for this sdBV star. Additionally, we are able to place interesting limits on any stellar or planetary companion to Feige 48."],["dc.identifier.doi","10.1111/j.1365-2966.2004.07438.x"],["dc.identifier.isi","000220088100006"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/48630"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0035-8711"],["dc.title","Observations of the pulsating subdwarf B star Feige 48: Constraints on evolution and companions"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","639"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","654"],["dc.bibliographiccitation.volume","401"],["dc.contributor.author","Kepler, S. O."],["dc.contributor.author","Nather, R. E."],["dc.contributor.author","Winget, D. E."],["dc.contributor.author","Nitta, A."],["dc.contributor.author","Kleinman, S. J."],["dc.contributor.author","Metcalfe, T."],["dc.contributor.author","Sekiguchi, K."],["dc.contributor.author","Xiaojun, Jiang"],["dc.contributor.author","Sullivan, D."],["dc.contributor.author","Sullivan, T."],["dc.contributor.author","Janulis, R."],["dc.contributor.author","Meistas, E."],["dc.contributor.author","Kalytis, R."],["dc.contributor.author","Krzesinski, J."],["dc.contributor.author","Ogloza, W."],["dc.contributor.author","Zola, S."],["dc.contributor.author","O'Donoghue, D."],["dc.contributor.author","Romero-Colmenero, E."],["dc.contributor.author","Martinez, P."],["dc.contributor.author","Dreizler, S."],["dc.contributor.author","Deetjen, J."],["dc.contributor.author","Nagel, T."],["dc.contributor.author","Schuh, S. L."],["dc.contributor.author","Vauclair, G."],["dc.contributor.author","Ning, Fu Jian"],["dc.contributor.author","Chevreton, M."],["dc.contributor.author","Solheim, J.-E."],["dc.contributor.author","Perez, J. M. Gonzalez"],["dc.contributor.author","Johannessen, F."],["dc.contributor.author","Kanaan, A."],["dc.contributor.author","Costa, J. E."],["dc.contributor.author","Murillo Costa, A. F."],["dc.contributor.author","Wood, M. A."],["dc.contributor.author","Silvestri, N."],["dc.contributor.author","Ahrens, T. J."],["dc.contributor.author","Jones, A. K."],["dc.contributor.author","Collins, A. E."],["dc.contributor.author","Boyer, M."],["dc.contributor.author","Shaw, J. S."],["dc.contributor.author","Mukadam, A."],["dc.contributor.author","Klumpe, E. W."],["dc.contributor.author","Larrison, J."],["dc.contributor.author","Kawaler, S."],["dc.contributor.author","Riddle, R."],["dc.contributor.author","Ulla, A."],["dc.contributor.author","Bradley, P."],["dc.date.accessioned","2019-07-09T11:53:31Z"],["dc.date.available","2019-07-09T11:53:31Z"],["dc.date.issued","2003"],["dc.description.abstract","We report 323 hours of nearly uninterrupted time series photometric observations of the DBV star GD 358 acquired with the Whole Earth Telescope (WET) during May 23rd to June 8th, 2000. We acquired more than 232 000 independent measurements. We also report on 48 hours of time-series photometric observations in Aug 1996. We detected the non-radial g-modes consistent with degree ` = 1 and radial order 8 to 20 and their linear combinations up to 6th order. We also detect, for the first time, a high amplitude ` = 2 mode, with a period of 796 s. In the 2000 WET data, the largest amplitude modes are similar to those detected with the WET observations of 1990 and 1994, but the highest combination order previously detected was 4th order. At one point during the 1996 observations, most of the pulsation energy was transferred into the radial order k = 8 mode, which displayed a sinusoidal pulse shape in spite of the large amplitude. The multiplet structure of the individual modes changes from year to year, and during the 2000 observations only the k = 9 mode displays clear normal triplet structure. Even though the pulsation amplitudes change on timescales of days and years, the eigenfrequencies remain essentially the same, showing the stellar structure is not changing on any dynamical timescale."],["dc.identifier.doi","10.1051/0004-6361:20030105"],["dc.identifier.fs","20311"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/7683"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/60437"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.orgunit","Fakultät für Physik"],["dc.rights","Goescholar"],["dc.rights.access","openAccess"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.title","The everchanging pulsating white dwarf GD358"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","L25"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","L28"],["dc.bibliographiccitation.volume","448"],["dc.contributor.author","Nagel, T."],["dc.contributor.author","Schuh, Sonja"],["dc.contributor.author","Kusterer, D. J."],["dc.contributor.author","Stahn, Thorsten"],["dc.contributor.author","Hugelmeyer, S. D."],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Gansicke, B. T."],["dc.contributor.author","Schreiber, M. R."],["dc.date.accessioned","2018-11-07T10:09:39Z"],["dc.date.available","2018-11-07T10:09:39Z"],["dc.date.issued","2006"],["dc.description.abstract","Aims. The archival spectrum of SDSS J212531.92- 010745.9 shows not only the typical signature of a PG1159 star, but also indicates the presence of a companion. Our aim was the proof of the binary nature of this object and the determination of its orbital period. Methods. We performed time-series photometry of SDSS J212531.92-010745.9. We observed the object during 10 nights, spread over one month, with the Tubingen 80 cm and the Gottingen 50 cm telescopes. We fitted the observed light curve with a sine and simulated the light curve of this system with the nightfall program. Furthermore, we compared the spectrum of SDSS J212531.92-010745.9 with NLTE models, the results of which also constrain the light curve solution. Results. An orbital period of 6.95616(33) h with an amplitude of 0.354(3) mag is derived from our observations. A pulsation period could not be detected. For the PG1159 star we found, as preliminary results from comparison with our NLTE models, T-eff similar to 90 000 K, log g similar to 7.60, and the abundance ratio C C/He similar to 0.05 by number fraction. For the companion we obtained with a mean radius of 0.4 +/- 0.1 R-., amass of 0.4 +/- 0.1 M-., and a temperature of 8200 K on the irradiated side, good agreement between the observed light curve and the, nightfall simulation, but we do not regard those values as final."],["dc.identifier.doi","10.1051/0004-6361:200600009"],["dc.identifier.isi","000235777700005"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/7679"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/39691"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","0004-6361"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","SDSS J212531.92-010745.9 - the first definite PG 1159 close binary system"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","367"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","372"],["dc.bibliographiccitation.volume","464"],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Schuh, Sonja"],["dc.contributor.author","Homeier, Derek"],["dc.date.accessioned","2018-11-07T11:04:13Z"],["dc.date.available","2018-11-07T11:04:13Z"],["dc.date.issued","2007"],["dc.description.abstract","Context. The Optical Gravitational Lensing Experiment project has recently provided the OGLE III list of low-luminosity object transits from campaigns # 3 and # 4, reporting 40 new objects exhibiting the low-amplitude photometric eclipses expected for exoplanets. Compared to previous OGLE targets, these OGLE III candidates have been more restrictively selected and may contain low-mass planets. Aims. We have secured follow-up low-resolution spectroscopy for 28 candidates out of this list ( and one from the OGLE Carina fields) to obtain an independent characterization of the primary stars by spectral classification and thus better constrain the parameters of their companions. Methods. We fed the constraints from these results back into an improved light curve solution. Together with the radius ratios from the transit measurements, we derived the radii of the low-luminosity companions. This allows us to examine the possible sub-stellar nature of these objects. Results. Sixteen of the companions can be clearly identified as low-mass stars orbiting a main sequence primary, while 10 more objects are likely to have red giant primaries and therefore also host a stellar companion; 3 possibly have a sub-stellar nature (R <= 0.15 R-circle dot). Conclusions. The planetary nature of these objects should therefore be confirmed by dynamical mass determinations."],["dc.identifier.doi","10.1051/0004-6361:20054362"],["dc.identifier.fs","297835"],["dc.identifier.isi","000244407900038"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/7677"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/51787"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","0004-6361"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","Spectral types of planetary host star candidates from OGLE III"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]