Schuh, Sonja

[["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","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","219"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","228"],["dc.bibliographiccitation.volume","473"],["dc.contributor.author","Tillich, A."],["dc.contributor.author","Heber, Ulrich"],["dc.contributor.author","O'Toole, S. J."],["dc.contributor.author","Ostensen, Roy H."],["dc.contributor.author","Schuh, Sonja"],["dc.date.accessioned","2018-11-07T10:57:55Z"],["dc.date.available","2018-11-07T10:57:55Z"],["dc.date.issued","2007"],["dc.description.abstract","Context. Stellar oscillations are an important tool to probe the interior of a star. Subdwarf B stars are core helium burning objects, but their formation is poorly understood as neither single star nor binary evolution can fully explain their observed properties. Since 1997, an increasing number of sdB stars has been found to pulsate forming two classes of stars, the V361 Hya and V1093 Her stars. Aims. We focus on the bright V 361 Hya star PG 1605+ 072 to characterise its frequency spectrum. While most previous studies relied on light variations, we have measured radial velocity variations for as many as 20 modes. In this paper, we aim at characterising the modes from atmospheric parameter and radial velocity variations. Methods. Time resolved spectroscopy (approximate to 9000 spectra) has been carried out to detect line profile variations from which variations of the effective temperature and gravity are extracted by means of a quantitative spectral analysis. Results. We measured variations of effective temperatures and gravities for eight modes with semi- amplitudes ranging from Delta T-eff = 880 K to as small as 88 K, and. log g of 0.08 dex to as low as 0.008 dex. Gravity and temperature vary almost in phase, whereas phase lags are found between temperature and radial velocity. Conclusions. This profound analysis of a unique data set serves as a sound basis for the next step towards an identification of pulsation modes. As rotation may play an important role, the modelling of pulsation modes is challenging but feasible."],["dc.identifier.doi","10.1051/0004-6361:20077949"],["dc.identifier.isi","000249957800024"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9075"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/50363"],["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.rights","Goescholar"],["dc.rights.access","openAccess"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.title","The multi-site spectroscopic telescope campaign - II. effective temperature and gravity variations in the multi-periodic pulsating subdwarf B star PG 1605+072"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","submitted_version"],["dspace.entity.type","Publication"]]