Recent Observations of PMS δ Scuti Stars

2003 ◽  
pp. 69-72
Author(s):  
Vincenzo Ripepi
Keyword(s):  
Scuti Stars ◽  
Δ Scuti Stars

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.

scholarly journals Non-Adiabatic Seismic Study of The Thin Convective Envelope of δ Scuti Stars

2004 ◽  
Vol 193 ◽  
pp. 470-473
Author(s):  
M.-A. Dupret ◽  
A. Grigahcène ◽  
R. Garrido ◽  
J. Montalban ◽  
M. Gabriel ◽  
...  
Keyword(s):  
Instability Strip ◽  
Full Spectrum ◽  
Convective Envelope ◽  
Theoretical Predictions ◽  
Mode Stability ◽  
Different Color ◽  
Mixing Length Theory ◽  
Scuti Stars ◽  
Δ Scuti Stars ◽  
Phase Differences

AbstractFor δ Sct stars, the theoretical predictions of a non-adiabatic pulsation code are very dependent on the characteristics of the thin convective envelope of the models (Balona & Evers 1999). The treatment of the non-adiabatic interaction between convection and pulsation also has a significant impact on the results, particularly near the red edge of the instability strip. The non-adiabatic theoretical predictions can be tested upon observations by comparing them to the amplitude ratios and phase differences as observed in different color passbands (Dupret et al. 2003). In the first part of this paper, we compare the results obtained by adopting different treatments of convection in the interior and atmosphere models: mixing-length theory (MLT) and full spectrum of turbulence (FST) (Canuto et al. 1996, CGM). In the second part, we examine the problem of the interaction between convection and pulsation and compare the mode stability obtained with and without including time-dependent convection in our non-adiabatic code.

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 Pulsation frequency distribution in δ Scuti stars

2015 ◽  
Vol 452 (3) ◽  
pp. 3073-3084 ◽  
Author(s):  
L. A. Balona ◽  
J. Daszyńska-Daszkiewicz ◽  
A. A. Pamyatnykh
Keyword(s):  
Frequency Distribution ◽  
Pulsation Frequency ◽  
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 Catalogue and properties of δ Scuti stars in binaries

2016 ◽  
Vol 465 (1) ◽  
pp. 1181-1200 ◽  
Author(s):  
Alexios Liakos ◽  
Panagiotis Niarchos
Keyword(s):  
Scuti Stars ◽  
Δ Scuti Stars

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 New Progress in Mode Detection and Identification in δ Scuti Stars by the Analysis of Line Profile Variations

2000 ◽  
Vol 176 ◽  
pp. 463-464
Author(s):  
L. Mantegazza ◽  
E. Poretti ◽  
M. Bossi ◽  
N. S. Nuñez ◽  
A. Sacchi ◽  
...  
Keyword(s):  
High Resolution ◽  
Line Profile ◽  
High Resolution Spectroscopy ◽  
Line Profiles ◽  
Powerful Technique ◽  
Mode Detection ◽  
Detection And Identification ◽  
Scuti Stars ◽  
Δ Scuti Stars ◽  
Nonradial Pulsation

Abstractδ Sct stars are among the most promising targets to perform ground-based asteroseismology. High resolution spectroscopy offers us a powerful technique to identify radial and nonradial pulsation modes, since we can easily detect oscillations and travelling features in the line profiles.

Sign in / Sign up

Export Citation Format

Share Document