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 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 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 Finding binaries from phase modulation of pulsating stars with Kepler – VI. Orbits for 10 new binaries with mischaracterized primaries

2020 ◽  
Vol 493 (4) ◽  
pp. 5382-5388
Author(s):  
Simon J Murphy ◽  
Nicholas H Barbara ◽  
Daniel Hey ◽  
Timothy R Bedding ◽  
Ben D Fulcher
Keyword(s):  
Phase Modulation ◽  
White Dwarfs ◽  
Binary Systems ◽  
Main Sequence ◽  
Classification Algorithm ◽  
Orbital Parameters ◽  
Pulsating Stars ◽  
Stellar Properties ◽  
Scuti Stars ◽  
Δ Scuti Stars

ABSTRACT Measuring phase modulation in pulsating stars has proven to be a highly successful way of finding binary systems. The class of pulsating main-sequence A and F variables, known as δ Scuti stars consists of particularly good targets for this, and the Kepler sample of these has been almost fully exploited. However, some Keplerδ Scuti stars have incorrect temperatures in stellar properties catalogues, and were missed in previous analyses. We used an automated pulsation classification algorithm to find 93 new δ Scuti pulsators among tens of thousands of F-type stars, which we then searched for phase modulation attributable to binarity. We discovered 10 new binary systems and calculated their orbital parameters, which we compared with those of binaries previously discovered in the same way. The results suggest that some of the new companions may be white dwarfs.

scholarly journals Frequency analysis of δ Scuti stars towards the Galactic bulge

2021 ◽  
Author(s):  
H Netzel ◽  
P Pietrukowicz ◽  
I Soszyński ◽  
M Wrona
Keyword(s):  
Frequency Analysis ◽  
Gravitational Lensing ◽  
Fundamental Mode ◽  
Statistical Properties ◽  
Galactic Bulge ◽  
Homogeneous Sample ◽  
Theoretical Predictions ◽  
Scuti Stars ◽  
Δ Scuti Stars

Abstract We have performed a frequency analysis of 10,092 δ Scuti-type stars detected in the fourth phase of the Optical Gravitational Lensing Experiment (OGLE) towards the Galactic bulge, which is the most numerous homogeneous sample of δ Scuti stars observed so far. The main goal was to search for stars pulsating in at least two radial modes simultaneously. We have found 3083 candidates for such stars, which is the largest set obtained to date. Among them, 2655 stars pulsate in two radial modes, 414 stars pulsate in three radial modes, and 14 stars pulsate in four radial modes at the same time. We report the identification of 221 δ Scuti stars pulsating in the fundamental mode, first overtone, and third overtone simultaneously. We show the most populated Petersen and Bailey diagrams and discuss statistical properties of the identified frequencies based on this numerous sample. Additionally, we present theoretical predictions of period ratios for δ Scuti stars pulsating in overtones from the fourth to the seventh.

scholarly journals A METHOD OF COLOR EXCESS DETERMINATION FOR HIGH AMPLITUDE δ SCUTI STARS

2009 ◽  
Vol 42 (6) ◽  
pp. 155-159
Author(s):  
Chul-Hee Kim ◽  
J.H. Choi ◽  
B.K. Moon ◽  
Soonthornthum Boonrucksar
Keyword(s):  
High Amplitude ◽  
Color Excess ◽  
Scuti Stars ◽  
Δ Scuti Stars

scholarly journals How to separate the low amplitude δ Scuti variation from the instrumental ones in CoRoT data?

2015 ◽  
Vol 11 (A29B) ◽  
pp. 529-531
Author(s):  
József M. Benkő ◽  
Margit Paparó
Keyword(s):  
Real Data ◽  
High Amplitude ◽  
Variable Stars ◽  
South Atlantic ◽  
Frequency Range ◽  
South Atlantic Anomaly ◽  
Fourier Spectra ◽  
Low Amplitude ◽  
Scuti Stars ◽  
Δ Scuti Stars

AbstractRich regular frequency patterns were found in the Fourier spectra of low-amplitude δ Scuti stars observed by CoRoT satellite (see Paparó et al. in prep.). The CoRoT observations are, however, influenced by the disturbing effect of the South Atlantic Anomaly. The effect is marginal for high amplitude variable stars but it could be critical in the case of low amplitude variables, especially if the frequency range of the intrinsic variation overlaps the interval of the instrumental frequencies. Some tests were carried out both on synthetic and real data for distinguishing technical and stars' frequencies.

scholarly journals CCD Photometry of the High‐Amplitude δ Scuti Stars V798 Cygni and V831 Tauri

1998 ◽  
Vol 110 (752) ◽  
pp. 1156-1163 ◽  
Author(s):  
F.  Musazzi ◽  
E.  Poretti ◽  
S.  Covino ◽  
A. Arellano  Ferro
Keyword(s):  
High Amplitude ◽  
Ccd Photometry ◽  
Scuti Stars ◽  
Δ Scuti Stars

scholarly journals Cluster Distances using Delta Scuti Stars; The Open Clusters Praesepe and NGC 7062

2002 ◽  
Vol 207 ◽  
pp. 135-137
Author(s):  
Torben Arentoft ◽  
Lars M. Freyhammer
Keyword(s):  
Chemical Composition ◽  
Open Cluster ◽  
Large Population ◽  
High Amplitude ◽  
Open Clusters ◽  
Distance Scale ◽  
Stellar Clusters ◽  
Delta Scuti ◽  
Scuti Stars ◽  
Δ Scuti Stars

Asteroseismology of multiperiodic δ Scuti stars is a powerful tool for providing estimates of distances to the stars being analyzed. Especially δ Scuti stars in clusters offer good possibilities for determining asteroseismic distances, as the stellar models are constrained by assuming common values for chemical composition, age and distance. Recently, we detected a large population of δ Scuti stars in the open cluster NGC 7062. On the basis of these results, we discuss the potential of extending the asteroseismic distance scale for δ Scuti stars to include extra-galactic stellar clusters. Especially high-amplitude δ Scuti stars, pulsating in at least 2 radial modes, offer promising possibilities for doing this.

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