In this paper we present our proposal to search for periodically variable stars in the exoplanet field data. In order to do so one first has to perform a quasiautomated frequency search in the data. Once the periodically variable stars are found, they have to be classified, e.g. by means of a statistical scheme analoguous to the one we developed for the classification of new B-type variables discovered from the HIPPARCOS data. After the classification of the variable stars, we plan to study the β Cep stars and the slowly pulsating B stars (SPBs) with the goal to derive constraints on their internal structure.
{"title":"The study of pulsating stars from the COROT exoplanet field data","authors":"C. Aerts","doi":"10.1553/CIA141S20","DOIUrl":"https://doi.org/10.1553/CIA141S20","url":null,"abstract":"In this paper we present our proposal to search for periodically variable stars in the exoplanet field data. In order to do so one first has to perform a quasiautomated frequency search in the data. Once the periodically variable stars are found, they have to be classified, e.g. by means of a statistical scheme analoguous to the one we developed for the classification of new B-type variables discovered from the HIPPARCOS data. After the classification of the variable stars, we plan to study the β Cep stars and the slowly pulsating B stars (SPBs) with the goal to derive constraints on their internal structure.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133124981","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}
From simulations of massive stars we flnd regular low-amplitude radial pulsations can be excited. Such pulsations were encountered during core hydrogen burning as well as during the early core helium burning stage of evolution. For four selected models we present light curves in the V-band. The results are discussed with the aim to guide observations to identify and monitor such regularly pulsating variable massive stars in nature.
{"title":"Pulsations of Luminous Blue Variables","authors":"E. Dorfi, A. Gautschy","doi":"10.1553/cia141s57","DOIUrl":"https://doi.org/10.1553/cia141s57","url":null,"abstract":"From simulations of massive stars we flnd regular low-amplitude radial pulsations can be excited. Such pulsations were encountered during core hydrogen burning as well as during the early core helium burning stage of evolution. For four selected models we present light curves in the V-band. The results are discussed with the aim to guide observations to identify and monitor such regularly pulsating variable massive stars in nature.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117280843","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}
The effects of rapid rotation on stellar pulsation is examined using an accurate 2D numerical method. We compare the results of these non-perturbative calculations with those of perturbative methods and find that frequency differences exceed 0.08 μHz on half of the modes when the rotation rate is 15% of the keplerian (break-up) limit. The differences between the two results is mainly attributed to the approximate treatment of the centrifugal force in perturbative methods. We also explore different levels of approximation for the Coriolis force.
{"title":"Oscillations of rapidly rotating stars","authors":"B. Dintrans, M. Rieutord","doi":"10.1553/CIA147S65","DOIUrl":"https://doi.org/10.1553/CIA147S65","url":null,"abstract":"The effects of rapid rotation on stellar pulsation is examined using an accurate 2D numerical method. We compare the results of these non-perturbative calculations with those of perturbative methods and find that frequency differences exceed 0.08 μHz on half of the modes when the rotation rate is 15% of the keplerian (break-up) limit. The differences between the two results is mainly attributed to the approximate treatment of the centrifugal force in perturbative methods. We also explore different levels of approximation for the Coriolis force.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133419685","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}
E. Paunzen, I. Andronov, L. Chinarova, M. König, M. Rode-Paunzen
The project of time series analysis for the photometric observations of a representative group of RV Tauri type stars is described. This class of variables consists of about 100 supergiants in the Milky Way. Their light curves show in general two unequal minima with several individual features which are not explained by now. The complementary methods of periodogram, scalegram and wavelet analysis as well as statistically optimal ts have been applied. This research will result in an atlas of the light curves within the time and phase domains. In addition, a catalog of the observational characteristics of variability including the time and magnitude of the extrema for the program stars will be computed. Statistical correlations between these characteristics will give a strict observational test for the theoretical models explaining the RV Tauri phenomenon.
{"title":"An extensive study of the photometric behaviour of RV Tauri variables","authors":"E. Paunzen, I. Andronov, L. Chinarova, M. König, M. Rode-Paunzen","doi":"10.1553/CIA147S126","DOIUrl":"https://doi.org/10.1553/CIA147S126","url":null,"abstract":"The project of time series analysis for the photometric observations of a representative group of RV Tauri type stars is described. This class of variables consists of about 100 supergiants in the Milky Way. Their light curves show in general two unequal minima with several individual features which are not explained by now. The complementary methods of periodogram, scalegram and wavelet analysis as well as statistically optimal ts have been applied. This research will result in an atlas of the light curves within the time and phase domains. In addition, a catalog of the observational characteristics of variability including the time and magnitude of the extrema for the program stars will be computed. Statistical correlations between these characteristics will give a strict observational test for the theoretical models explaining the RV Tauri phenomenon.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121941366","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}
This paper examines the prospect of observing δ Scuti variables with BRITE. In particular, some of the astrophysical questions, which can be investigated, are discussed together with the methods to be applied. Finally, the seven bright stars suitable for BRITE are presented.
{"title":"The BRITE satellite and Delta Scuti Stars: The Magnificent Seven","authors":"M. Breger","doi":"10.1553/CIA152S97","DOIUrl":"https://doi.org/10.1553/CIA152S97","url":null,"abstract":"This paper examines the prospect of observing δ Scuti variables with BRITE. In particular, some of the astrophysical questions, which can be investigated, are discussed together with the methods to be applied. Finally, the seven bright stars suitable for BRITE are presented.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120973207","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}
A data reduction pipeline specifically developed for space-based open-field photometry obtained with the MOST satellite is presented. The reduction steps include correction of cosmic ray events, identification and rejection of exposures showing distorted images due to pointing instabilities and efficient correction of stray light influences on the CCD. Considering the planned instrumentation for the BRITE mission, suggestions for an efficient data reduction based on the experiences with MOST are made. It is concluded that under the current specifications for the mission many of the developed techniques might be directly applicable for the development of a BRITE data reduction pipeline.
{"title":"A MOST open-field data reduction software and its applications to BRITE","authors":"D. Huber, P. Reegen","doi":"10.1553/CIA152S77","DOIUrl":"https://doi.org/10.1553/CIA152S77","url":null,"abstract":"A data reduction pipeline specifically developed for space-based open-field photometry obtained with the MOST satellite is presented. The reduction steps include correction of cosmic ray events, identification and rejection of exposures showing distorted images due to pointing instabilities and efficient correction of stray light influences on the CCD. Considering the planned instrumentation for the BRITE mission, suggestions for an efficient data reduction based on the experiences with MOST are made. It is concluded that under the current specifications for the mission many of the developed techniques might be directly applicable for the development of a BRITE data reduction pipeline.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128544252","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}
A. Moya, J. Suárez, P. Amado, S. Martín-Ruiz, A. Grigahcène, R. Garrido
In this work, a generic overview of the Frequency Ratio Method (FRM) is presented. The method is based on the rst-o rder asymptotic g-mode expression given by Tassoul (1980). It is particularly adapted for obtaining asteroseismological information of Doradus pulsating stars showing at least three pulsation frequencies. The method provides an identication of the radial order n and degree ‘ of observed frequencies and an estimate of the integral of the buoyancy frequency (Brunt{V weighted over the stellar radius along the radiative zone. Some insights on its applicability to observed frequencies of rotating Doradus stars are also mentioned.
{"title":"A new tool for the seismic investigation of γ Doradus stars","authors":"A. Moya, J. Suárez, P. Amado, S. Martín-Ruiz, A. Grigahcène, R. Garrido","doi":"10.1553/CIA147S129","DOIUrl":"https://doi.org/10.1553/CIA147S129","url":null,"abstract":"In this work, a generic overview of the Frequency Ratio Method (FRM) is presented. The method is based on the rst-o rder asymptotic g-mode expression given by Tassoul (1980). It is particularly adapted for obtaining asteroseismological information of Doradus pulsating stars showing at least three pulsation frequencies. The method provides an identication of the radial order n and degree ‘ of observed frequencies and an estimate of the integral of the buoyancy frequency (Brunt{V weighted over the stellar radius along the radiative zone. Some insights on its applicability to observed frequencies of rotating Doradus stars are also mentioned.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125625336","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}
It is evident that there is still no complete picture of how pulsation works in stars with convective envelopes. In the past few years the field of observing solartype oscillations has moved from ambiguous detections to firm measurements. However, I will demonstrate that BRITE is not an appropriate instrument to observe solar-type pulsation in sun-like stars, but rather perfectly suited to detect solar-type oscillations in stars cooler and more luminous than the Sun. Asteroseismology of red giants is still in its infancy and the few currently available high-precision data may not be adequate to answer the open questions. Using clever observing strategies, BRITE can help to significantly improve our understanding of the interaction between pulsation and convection, but also of stellar evolution during the important red giant phase in general.
{"title":"Exploring solar-type pulsation with BRITE","authors":"T. Kallinger","doi":"10.1553/CIA152S131","DOIUrl":"https://doi.org/10.1553/CIA152S131","url":null,"abstract":"It is evident that there is still no complete picture of how pulsation works in stars with convective envelopes. In the past few years the field of observing solartype oscillations has moved from ambiguous detections to firm measurements. However, I will demonstrate that BRITE is not an appropriate instrument to observe solar-type pulsation in sun-like stars, but rather perfectly suited to detect solar-type oscillations in stars cooler and more luminous than the Sun. Asteroseismology of red giants is still in its infancy and the few currently available high-precision data may not be adequate to answer the open questions. Using clever observing strategies, BRITE can help to significantly improve our understanding of the interaction between pulsation and convection, but also of stellar evolution during the important red giant phase in general.","PeriodicalId":151133,"journal":{"name":"Third Coast","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123835325","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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