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We combine photometric and spectroscopic data on twelve modes excited in FG Vir to determine their spherical harmonic degrees, $\ell$, and to obtain constraints on the star model. The effective temperature consistent with the mean colours…

In $\delta$ Scuti star models, the photometric amplitudes and phases exhibit a strong dependence on convection, which enters through the complex parameter, $f$, which describes the bolometric flux variation. We present a new method of…

Astrophysics · Physics 2007-05-23 J. Daszy{ń}ska-Daszkiewicz , W. A. Dziembowski , A. A. Pamyatnykh

In Delta Scuti star models, the calculated amplitude ratios and phase differences for multi-colour photometry exhibit a strong dependence on convection. These observables are tools for determination of the spherical harmonic degree of the…

Astrophysics · Physics 2009-11-07 J. Daszynska-Daszkiewicz , W. A. Dziembowski , A. A. Pamyatnykh

Extensive photometric multisite campaigns of the Delta Scuti variable FG Vir are presented. For the years 2003 and 2004, 926 hours of photometry at the millimag precision level were obtained. The combinations with earlier campaigns lead to…

This paper examines the mode identification and presents pulsation models for FG Vir, for which 24 frequencies have been detected. Histograms of the frequency spacings show peaks which are identified with adjacent radial orders and…

Astrophysics · Physics 2007-05-23 M. Breger , A. A. Pamyatnykh , H. Pikall , R. Garrido

We report on a multi-site photometric campaign on the high-amplitude $\delta$ Scuti star V2367 Cyg in order to determine the pulsation modes. We also used high-dispersion spectroscopy to estimate the stellar parameters and projected…

The results obtained by means of the photometric approach to the study of Delta Sct stars are extensively discussed. The different frequency contents of the three best candidates for asteroseismological studies (FG Vir, 4 CVn and XX Pyx)…

Astrophysics · Physics 2007-05-23 Ennio Poretti

We present a seismic study of $\delta$ Scuti based on a mode identification from multicoulor photometry. The dominant frequency can be associated only with a radial mode and the second frequency is, most probably, a dipole mode. The other…

Solar and Stellar Astrophysics · Physics 2021-05-26 Jadwiga Daszynska-Daszkiewicz , A. A. Pamyatnykh , P. Walczak , G. Handler , A. Pigulski , W. Szewczuk

We discuss here the pulsation properties of the $\delta$ Scuti star BV Circini on the basis of data obtained during a simultaneous photometric and spectroscopic campaign in 1996 and a spectroscopic one in 1998, and taking also advantage of…

Astrophysics · Physics 2009-10-31 Luciano Mantegazza , Ennio Poretti , Filippo M. Zerbi

I discuss a prospect for mode identification from two-passband photometry of forthcoming BRITE space mission. Examples of photometric diagnostic diagrams are shown for three types of main sequence pulsating variables: $\beta$ Cephei, Slowly…

Astrophysics · Physics 2009-11-13 Jadwiga Daszynska-Daszkiewicz

A high-accuracy multisite campaign was carried out from 2002 January to May with a photometric coverage of 398 hours at five observatories. The concentration on a few selected sites gives better consistency and accuracy than collecting…

We analyze data on pulsation amplitudes and phases for two $\beta$ Cephei stars, $\delta$ Cet and $\nu$ Eri. Str\"omgren photometry and radial velocity measurements are used simultaneously to obtain constraints on mean parameters of the…

Astrophysics · Physics 2009-11-11 J. Daszynska-Daszkiewicz , W. A. Dziembowski , A. A. Pamyatnykh

Only a fraction of the theoretically predicted nonradial pulsation modes have so far been observed in Delta Scuti stars. Nevertheless, the large number of frequencies detected in recent photometric studies of selected Delta Scuti stars…

Astrophysics · Physics 2015-05-13 M. Breger , P. Lenz , A. A. Pamyatnykh

The potential of photometric methods for the identification of l, the degree of spherical surface harmonic of a pulsating star, is investigated with special emphasis on Stromgren photometry applied to delta Scuti and gamma Dor variables.…

Astrophysics · Physics 2007-05-23 Rafael Garrido

Statistical analyses of several Delta Scuti stars (FG Vir, 44 Tau, BL Cam and others) show that the photometrically observed frequencies cluster around the frequencies of the radial modes over many radial orders. The observed regularities…

Astrophysics · Physics 2008-11-03 M. Breger , P. Lenz , A. A. Pamyatnykh

The main obstacle in exploiting the frequency data of $\delta$ Sct stars is difficulty in mode identification. The $\delta$ Sct oscillation spectra, unlike those of the Sun or white dwarfs, do not exhibit very regular patterns. Thus, the…

Astrophysics · Physics 2009-11-13 Jadwiga Daszyńska-Daszkiewicz

Space missions have produced an incredibly large database on pulsating stars. The light curves via the frequency content contain a detailed description of each star. The critical point is the identification of modes, especially in the…

Solar and Stellar Astrophysics · Physics 2013-08-27 M. Paparó , J. M. Benkő

We present new spectroscopic and photometric time series observations of the delta Scuti star FG~Vir. We detect the oscillations via changes in the equivalent widths of hydrogen and metal absorption lines. From the ratios between…

Astrophysics · Physics 2007-05-23 M. Viskum , H. Kjeldsen , T. R. Bedding , T. H. Dall , I. K. Baldry , H. Bruntt , S. Frandsen

The phenomenology associated with line profile variations in delta Scuti stars is reviewed. The three main techniques adopted to detect pulsation modes, i.e., the pixel-by-pixel analysis, the analysis of the moment time series and the…

Astrophysics · Physics 2007-05-23 L. Mantegazza

We have searched for photometric variability in 95 Vir, a fast rotating, chromospherically active early F-type star, which was observed in the framework of Campaign 6 of the Kepler K2 mission. Available literature information on 95 Vir were…

Solar and Stellar Astrophysics · Physics 2017-04-19 Ernst Paunzen , Stefan Huemmerich , Klaus Bernhard , Przemek Walczak
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