WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 13Multisite Photometric Campaign on the High-Amplitude Delta Scuti Star Kic 6382916(Oxford University Press, 2013) Ulusoy, Ceren; Ulas, B.; Guelmez, T.; Balona, L. A.; Stateva, I.; Iliev, I. Kh.; Carbognani, A.; 01. Izmir Institute of TechnologyWe present results of a multisite photometric campaign on the high-amplitude delta Scuti star KIC 6382916 in the Kepler field. The star was observed over a 85-d interval at five different sites in North America and Europe during 2011. Kepler photometry and ground-based multicolour light curves of KIC 6382916 are used to investigate the pulsational content and to identify the principal modes. High-dispersion spectroscopy was also obtained in order to derive the stellar parameters and projected rotational velocity. From an analysis of the Kepler time series, three independent frequencies and a few hundred combination frequencies are found. The light curve is dominated by two modes with frequencies f(1) = 4.9107 and f(2) = 6.4314 d(-1). The third mode with f(3) = 8.0350 d(-1) has a much lower amplitude. We attempt mode identification by examining the amplitude ratios and phase differences in different wavebands from multicolour photometry and comparing them to calculations for different spherical harmonic degree, l. We find that the theoretical models for f(1) and f(2) are in a best agreement with the observations and lead to value of l = 1 modes, but the mode identification of f(3) is uncertain due to its low amplitude. Non-adiabatic pulsation models show that frequencies below 6 d(-1) are stable, which means that the low frequency of f(1) cannot be reproduced. This is a further confirmation that current models predict a narrower pulsation frequency range than actually observed.Conference Object Citation - WoS: 9Citation - Scopus: 7Towards Ensemble Asteroseismology of the Young Open Clusters Chi Persei and Ngc 6910(John Wiley and Sons Inc., 2010) Saesen, S.; Pigulski, A.; Carrier, F.; Michalska, G.; Aerts, C.; De Ridder, J.; Zima, W.; 01. Izmir Institute of TechnologyAs a result of the variability survey in chi Persei and NGC 6910, the number of beta Cep stars that are members of these two open clusters is increased to twenty stars, nine in NGC 6910 and eleven in chi Persei. We compare pulsational properties, in particular the frequency spectra, of beta Cep stars in both clusters and explain the differences in terms of the global parameters of the clusters. We also indicate that the more complicated pattern of the variability among B-type stars in chi Persei is very likely caused by higher rotational velocities of stars in this cluster. We conclude that the sample of pulsating stars in the two open clusters constitutes a very good starting point for the ensemble asteroseismology of beta Cep-type stars and maybe also for other B-type pulsators. (C) 2010 WILEY-VCH Verlag GmbH&Co. KGaA, Weinheim