J. Pena, A. Arellano, J. Sareyan, R. Peña, M. Álvarez
uvbyβ photoelectric photometry of the RR Lyrae stars AE, RS, ST, TV, TW, UU, and XX Bootis has been acquired in order to determine the physical parameters of the stars. We used the correlation between the Fourier parameters derived from the light curves and the physical parameters such as the absolute magnitude Mv , intrinsic colour (B −V )0 and metal abundance [Fe/H]. Once reddening has been determined, unreddened indices are obtained and Teff and log g followed along the cycle, using a comparison with the theoretical models given for our determined metallicity.
{"title":"Physical parameter determination of seven RR Lyrae stars in Bootes","authors":"J. Pena, A. Arellano, J. Sareyan, R. Peña, M. Álvarez","doi":"10.1553/CIA150S385","DOIUrl":"https://doi.org/10.1553/CIA150S385","url":null,"abstract":"uvbyβ photoelectric photometry of the RR Lyrae stars AE, RS, ST, TV, TW, UU, and XX Bootis has been acquired in order to determine the physical parameters of the stars. We used the correlation between the Fourier parameters derived from the light curves and the physical parameters such as the absolute magnitude Mv , intrinsic colour (B −V )0 and metal abundance [Fe/H]. Once reddening has been determined, unreddened indices are obtained and Teff and log g followed along the cycle, using a comparison with the theoretical models given for our determined metallicity.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123743313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Schuh, F. Hessman, S. Dreizler, W. Kollatschny, W. Glatzel
The Gottingen stellar astrophysics group, headed by Stefan Dreizler, conducts research on extrasolar planets and their host stars, on lower-main sequence stars, and on evolved compact objects, in particular hot white dwarfs (including PG 1159 objects, magnetic WDs and cataclysmic variables), and subdwarf B stars. In addition to sophisticated NLTE spectral analyses of these stars, which draw on the extensive stellar atmosphere modelling experience of the group, we actively develop and apply a variety of photometric monitoring and time-resolved spectroscopic techniques to address time-dependent phenomena. With the new instrumentational developments described below, we plan to continue the study of variable white dwarfs (GW Vir, DB and ZZ Ceti variables) and in particular sdB EC 14026 and PG 1617 pulsators which already constitute a main focus, partly within the Whole Earth Telescope (WET/DARC), http://www.physics.udel.edu/∼jlp/darc/) collaboration, on a new level. Additional interest is directed towards strange mode instabilities in Wolf Rayet stars.
{"title":"MONET, HET and SALT and asteroseismological observations and theory in Göttingen","authors":"S. Schuh, F. Hessman, S. Dreizler, W. Kollatschny, W. Glatzel","doi":"10.1553/CIA150S317","DOIUrl":"https://doi.org/10.1553/CIA150S317","url":null,"abstract":"The Gottingen stellar astrophysics group, headed by Stefan Dreizler, conducts research on extrasolar planets and their host stars, on lower-main sequence stars, and on evolved compact objects, in particular hot white dwarfs (including PG 1159 objects, magnetic WDs and cataclysmic variables), and subdwarf B stars. In addition to sophisticated NLTE spectral analyses of these stars, which draw on the extensive stellar atmosphere modelling experience of the group, we actively develop and apply a variety of photometric monitoring and time-resolved spectroscopic techniques to address time-dependent phenomena. With the new instrumentational developments described below, we plan to continue the study of variable white dwarfs (GW Vir, DB and ZZ Ceti variables) and in particular sdB EC 14026 and PG 1617 pulsators which already constitute a main focus, partly within the Whole Earth Telescope (WET/DARC), http://www.physics.udel.edu/∼jlp/darc/) collaboration, on a new level. Additional interest is directed towards strange mode instabilities in Wolf Rayet stars.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132429113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Frandsen, H. Bruntt, F. Grundahl, G. Kopacki, R. Gilliland, E. Michel, T. Bedding, H. Kjeldsen, T. Arentoft, D. Stello, J. Mathiasen, P. Edmonds, A. Jacob
A large CCD photometry campaign has been organized, where more than 6000 frames were collected, to search for solar-like oscillations among K-giants in M4. The results are presented here with the main result being: amplitudes are below predictions.
{"title":"A search for solar-type oscillations in K giants in M4","authors":"S. Frandsen, H. Bruntt, F. Grundahl, G. Kopacki, R. Gilliland, E. Michel, T. Bedding, H. Kjeldsen, T. Arentoft, D. Stello, J. Mathiasen, P. Edmonds, A. Jacob","doi":"10.1553/CIA150S139","DOIUrl":"https://doi.org/10.1553/CIA150S139","url":null,"abstract":"A large CCD photometry campaign has been organized, where more than 6000 frames were collected, to search for solar-like oscillations among K-giants in M4. The results are presented here with the main result being: amplitudes are below predictions.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124322026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Having a rich acoustic oscillation spectrum makes solar-like stars particularly interesting for studying fluid-dynamical aspects of the stellar interior. I present some of the recent progress in formulating the physical processes that drive the acoustic oscillations to the observed amplitudes via their coupling with the turbulent velocity field in the outer convectively unstable stellar layers. I shall also discuss some asteroseismic diagnostic techniques that allow us to measure some of the gross stellar properties derived from a seismic signature contained in the variation of the large frequency separation of measured low-degree acoustic modes.
{"title":"Theoretical asteroseismology of solar-like oscillations","authors":"G. Houdek","doi":"10.1553/CIA150S122","DOIUrl":"https://doi.org/10.1553/CIA150S122","url":null,"abstract":"Having a rich acoustic oscillation spectrum makes solar-like stars particularly interesting for studying fluid-dynamical aspects of the stellar interior. I present some of the recent progress in formulating the physical processes that drive the acoustic oscillations to the observed amplitudes via their coupling with the turbulent velocity field in the outer convectively unstable stellar layers. I shall also discuss some asteroseismic diagnostic techniques that allow us to measure some of the gross stellar properties derived from a seismic signature contained in the variation of the large frequency separation of measured low-degree acoustic modes.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124882396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Molenda–Żakowicz, T. Arentoft, H. Kjeldsen, M. Vaňko
We describe our program of ground-based spectroscopic and photometric observations of stars selected to be scientific targets in the Kepler Asteroseismic Program.
我们描述了我们的计划，基于地面光谱和光度观测的恒星被选为科学目标的开普勒星震计划。
{"title":"Solar-like Oscillations with Kepler","authors":"J. Molenda–Żakowicz, T. Arentoft, H. Kjeldsen, M. Vaňko","doi":"10.1553/CIA150S143","DOIUrl":"https://doi.org/10.1553/CIA150S143","url":null,"abstract":"We describe our program of ground-based spectroscopic and photometric observations of stars selected to be scientific targets in the Kepler Asteroseismic Program.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114219483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I review recent results of the observations of magnetoacoustic p-mode oscillations in roAp stars with the focus on time-resolved spectroscopic studies. Time-series spectroscopy of roAp stars reveals unexpected and diverse pulsational behaviour in the spectral lines of different chemical elements. These unique pulsational characteristics arise from an interplay between the short vertical length of pulsation waves and extreme chemical stratification in the atmospheres of peculiar stars. This enables a tomographic reconstruction of the depth-dependence of the chemical composition and pulsation wave properties. The combination of magnetoacoustic tomography with Doppler imaging of the horizontal non-radial pulsation pattern opens the possibility for an unprecedented three-dimensional mapping of roAp star atmospheres.
{"title":"Observations of pulsations in roAp stars","authors":"O. Kochukhov","doi":"10.1553/cia150s39","DOIUrl":"https://doi.org/10.1553/cia150s39","url":null,"abstract":"I review recent results of the observations of magnetoacoustic p-mode oscillations in roAp stars with the focus on time-resolved spectroscopic studies. Time-series spectroscopy of roAp stars reveals unexpected and diverse pulsational behaviour in the spectral lines of different chemical elements. These unique pulsational characteristics arise from an interplay between the short vertical length of pulsation waves and extreme chemical stratification in the atmospheres of peculiar stars. This enables a tomographic reconstruction of the depth-dependence of the chemical composition and pulsation wave properties. The combination of magnetoacoustic tomography with Doppler imaging of the horizontal non-radial pulsation pattern opens the possibility for an unprecedented three-dimensional mapping of roAp star atmospheres.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120908836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I give a summary of results from the WIRE satellite, which has been used to observe bright stars from 1999–2000 and 2003–2006. The WIRE targets are monitored for up to five weeks with a duty cycle of 30–40%. The aim has been to characterize the flux variation of stars across the Hertzsprung-Russell diagram. I present an overview of the results for solar-like stars, δ Scuti stars, giant stars, and eclipsing binaries.
{"title":"Asteroseismology with the WIRE satellite","authors":"H. Bruntt","doi":"10.1553/cia150s326","DOIUrl":"https://doi.org/10.1553/cia150s326","url":null,"abstract":"I give a summary of results from the WIRE satellite, which has been used to observe bright stars from 1999–2000 and 2003–2006. The WIRE targets are monitored for up to five weeks with a duty cycle of 30–40%. The aim has been to characterize the flux variation of stars across the Hertzsprung-Russell diagram. I present an overview of the results for solar-like stars, δ Scuti stars, giant stars, and eclipsing binaries.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121181006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I review recent theoretical work on rapidly oscillating Ap stars and discuss key aspects of the physics of the oscillations observed in this class of pulsators.
我回顾了最近关于快速振荡Ap星的理论工作，并讨论了在这类脉冲星中观测到的振荡物理的关键方面。
{"title":"Theory of rapidly oscillating Ap stars","authors":"M. Cunha","doi":"10.1553/cia150s48","DOIUrl":"https://doi.org/10.1553/cia150s48","url":null,"abstract":"I review recent theoretical work on rapidly oscillating Ap stars and discuss key aspects of the physics of the oscillations observed in this class of pulsators.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115559387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this contribution, we present the high–resolution observations we obtained for HIP 113790 at the Haute-Provence Observatory using the AURELIE spectrograph. By determing its fundamental parameters, we confirm that the star is located in the δ Scuti instability strip. We further report the detection of rapid line profile variations with a period of about 1.43 hours.
{"title":"Spectroscopy of HIP 113790 at the 5th OHP NEON summer school","authors":"Y. Frémat, A. Antonova, Y. Damerdji","doi":"10.1553/CIA148S77","DOIUrl":"https://doi.org/10.1553/CIA148S77","url":null,"abstract":"In this contribution, we present the high–resolution observations we obtained for HIP 113790 at the Haute-Provence Observatory using the AURELIE spectrograph. By determing its fundamental parameters, we confirm that the star is located in the δ Scuti instability strip. We further report the detection of rapid line profile variations with a period of about 1.43 hours.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120984526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. E. Mølholt, S. Frandsen, F. Grundahll, L. Glowienka
{"title":"NGC 2660 revisited","authors":"T. E. Mølholt, S. Frandsen, F. Grundahll, L. Glowienka","doi":"10.1553/CIA148S12","DOIUrl":"https://doi.org/10.1553/CIA148S12","url":null,"abstract":"","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122391229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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