scholarly journals The Fourier Decomposition of the Light Curves of High Amplitude δ Set Stars

2000 ◽  
Vol 176 ◽  
pp. 83-84 ◽  
Author(s):  
Ennio Poretti
Keyword(s):  
Physical Properties ◽  
High Amplitude ◽  
Light Curves ◽  
Fourier Decomposition ◽  
Systematic Application ◽  
Scuti Stars

AbstractA significant improvement of the relationships between observed and physical properties of high amplitude δ Scuti stars (HADS), SX Phe stars, and RRc stars can be obtained by the systematic application of Fourier decomposition to their light curves.

scholarly journals Bulge δ Scuti stars in the MACHO database

1997 ◽  
Vol 189 ◽  
pp. 293-298
Author(s):  
D. Minniti ◽  
C. Alcock ◽  
D.R. Alves ◽  
T.S. Axelrod ◽  
A.C. Becker ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
High Amplitude ◽  
Light Curves ◽  
Evolutionary Status ◽  
Absolute Magnitudes ◽  
Scuti Stars ◽  
Δ Scuti Stars

We describe the search for δ Scuti stars in the MACHO database of bulge fields. Concentrating on a sample of high amplitude δ Scutis, we examine the light curves and pulsation modes. We also discuss their spatial distribution and evolutionary status using mean colors and absolute magnitudes.

scholarly journals Luminosity of δ Scuti Stars After Hipparcos Satellite

1998 ◽  
Vol 11 (1) ◽  
pp. 567-567
Author(s):  
E. Antonello ◽  
L. Mantegazza ◽  
E. Poretti
Keyword(s):  
Globular Clusters ◽  
Rotational Velocity ◽  
High Amplitude ◽  
Empirical Dependence ◽  
Trigonometric Parallaxes ◽  
Nearby Stars ◽  
Observational Errors ◽  
Absolute Magnitudes ◽  
Scuti Stars ◽  
Δ Scuti Stars

The absolute magnitudes of δ Scuti stars derived from parallaxes measured by the Hipparcos satellite were compared with the previous estimates based on photometric uvby² indices, and significant differences were found which are related to photometric effects of metallicity and rotational velocity. A reliable calibration of Mv in terms of the photometric indices shall include an estimate of these effects. It is important also to take into account the possible presence of unresolved close companions in order to fully exploit the accuracy of Mv of nearby stars derived from the trigonometric parallaxes. The Mv of few bright SX Phe stars support the period-luminosity relation obtained with ground based observations of globular clusters, while it does not seem to confirm the empirical dependence of this relation on the metallicity. Some high amplitude δ Scuti stars with intermediate or normal metallicity and small and uncertain parallax have apparently a very low luminosity. Simulations of Mv determinations from observed parallaxes based on the discussion of observational errors by Lutz and Kelker (1973) have shown that the low luminosity could be an effect related to these errors.

The MACHO Project Sample of Galactic Bulge High‐Amplitude δ Scuti Stars: Pulsation Behavior and Stellar Properties

2000 ◽  
Vol 536 (2) ◽  
pp. 798-815 ◽  
Author(s):  
C. Alcock ◽  
R. A. Allsman ◽  
D. R. Alves ◽  
T. S. Axelrod ◽  
A. C. Becker ◽  
...  
Keyword(s):  
High Amplitude ◽  
Galactic Bulge ◽  
Stellar Properties ◽  
Scuti Stars ◽  
Δ Scuti Stars

scholarly journals Fractal analysis applied to light curves of δ Scuti stars★

2018 ◽  
Author(s):  
S de Franciscis ◽  
J Pascual-Granado ◽  
J C Suárez ◽  
A García Hernández ◽  
R Garrido
Keyword(s):  
Fractal Analysis ◽  
Light Curves ◽  
Scuti Stars ◽  
Δ Scuti Stars

scholarly journals Understanding Type II Supernovae

2005 ◽  
Vol 192 ◽  
pp. 275-280 ◽  
Author(s):  
L. Zampieri ◽  
M. Ramina ◽  
A. Pastorello
Keyword(s):  
Physical Properties ◽  
Large Range ◽  
Simultaneous Analysis ◽  
Light Curves ◽  
Physical Parameters ◽  
Expansion Velocity ◽  
Type Ii ◽  
Strong Correlations ◽  
Systematic Analysis ◽  
Robust Estimates

SummaryWe present the results of a systematic analysis of a group of Type II plateau supernovae that span a large range in luminosities, from faint objects like SN 1997D and 1999br to very luminous events like SN 1992am. The physical properties of the supernovae appear to be related to the plateau luminosity or the expansion velocity. The simultaneous analysis of the observed light curves, line velocities and continuum temperatures leads us to robust estimates of the physical parameters of the ejected envelope. We find strong correlations among several parameters. The implications of these results regarding the nature of the progenitor, the central remnant and the Ni yield are also addressed.

scholarly journals Accurate Fourier Decomposition of Cepheid Radial Velocity Curves

2000 ◽  
Vol 176 ◽  
pp. 233-234 ◽  
Author(s):  
P. Moskalik ◽  
T. Krzyt ◽  
N. A. Gorynya ◽  
N. N. Samus
Keyword(s):  
Radial Velocity ◽  
Light Curves ◽  
Fourier Decomposition ◽  
Hydrodynamical Models ◽  
Classical Cepheid

AbstractThe shapes of light curves and of radial velocity curves are two main predictions of the hydrodynamical models of Cepheids. Of the two, the velocity curves are more robust numerically and therefore, more suitable for comparison with the observations. In this report, we present accurate Fourier parameters for an extensive set of classical Cepheid velocity curves. Published radiative models reproduce the observations very well, with only small discrepancies present. We estimate the center of the ω2 = 2ω0 resonance to occur at Pr = 9.947 ± 0.051 day

scholarly journals On the Application of Fourier Decomposition Parameters

1993 ◽  
Vol 134 ◽  
pp. 157-158
Author(s):  
J. O. Petersen
Keyword(s):  
Fourier Analysis ◽  
Light Curves ◽  
Amplitude Ratios ◽  
Fourier Decomposition ◽  
Practical Applications ◽  
Convincing Argument ◽  
Lee Form ◽  
Modern Form ◽  
Made In ◽  
Phase Differences

The application of Fourier decomposition parameters has revolutionized important areas of investigations of Cepheid type variables since the introduction of Fourier analysis in its modern form by Simon and Lee (1981).In the literature several different representations of the results of Fourier analysis have been utilized. In view of the growing interest for applications of Fourier decomposition it is important to use and publish Fourier data in an optimal way. Most studies until now have used amplitude ratios and phase differences derived from traditional light curves giving the light variation in magnitudes, following the original recipe of Simon and Lee (1981). However, Stellingwerf and Donohoe (1986) advocated the use of phases rather than phase differences. Recently, Buchler et al. (1990) argued that the standard Simon & Lee form contains all relevant physics, and suggested analysis of flux-values rather than of magnitudes, because this removes the distorting effects of constant, false light. Thus there are many choices to be made in practical applications of Fourier analysis, and there is at present no convincing argument for preferring one specific representation.

scholarly journals Theoretical UBVI Light Curves of Pulsating Stars

2000 ◽  
Vol 176 ◽  
pp. 334-337
Author(s):  
Michael U. Feuchtinger ◽  
Ernst A. Dorfi
Keyword(s):  
Radiative Transfer ◽  
Light Curves ◽  
Rr Lyrae Stars ◽  
Fourier Decomposition ◽  
Pulsating Stars ◽  
Rr Lyrae ◽  
Stellar Pulsation ◽  
Sample Application ◽  
Lyrae Stars ◽  
Good Agreement

AbstractBy performing detailed frequency-dependent radiative transfer computations we are able to calculate light curves in particular bandpasses from stellar pulsation models calculated by the Vienna nonlinear convective pulsation code. As a sample application we discuss UBVI light curves of RR Lyrae stars. The properties of these light curves are analyzed by means of standard Fourier decomposition, and a comparison to recent observations is performed. As main results we find a good agreement with important observed RR Lyrae properties like pulsation amplitudes and Fourier parameters in B, V, and I bands. Additionally, from the synthetic color curves we derive linear transformation laws between amplitudes as well as Fourier parameters in the different bandpasses.

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