Fundamental parameters of rr lyrae stars from multicolour photometry and kurucz atmospheric models - III. SW and, DH peg, CU Com and DY peg

S. Barcza, J. Benkő

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We report the most comprehensive UBV(RI)C observations of the bright, radially pulsating field stars SW And, DH Peg, CU Com and DY Peg. Long-term variation has been found in the ultraviolet colour curves of SW And and DH Peg. We apply our photometric-hydrodynamic method to determine the fundamental parameters of these stars: metallicity, reddening, distance, mass, radius, equilibrium luminosity and effective temperature. Our method works well for SW And, CU Com and DY Peg. A very small mass 0.26 ± 0.04 M⊙ of SW And has been found. The fundamental parameters of CU Com are those of a normal double-mode RR Lyrae (RRd) star. DY Peg has been found to have paradoxical astrophysical parameters: the metallicity, mass and period are characteristic of a high-amplitude δ Sct star while the luminosity and radius place it in the group of RR Lyrae stars. DH Peg has been found to be peculiar: the definite instability in the colour curves towards ultraviolet; the dynamical variability of the atmosphere during the shocked phases suggests that the main assumptions of our photometric-hydrodynamic method, the quasi-static atmosphere approximation (QSAA) and the exclusive excitation of radial modes are probably not satisfied in this star. The fundamental parameters of all stars studied in this series of papers are summarized in tabular and graphical form.

Original languageEnglish
Pages (from-to)1863-1876
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume442
Issue number2
DOIs
Publication statusPublished - 2014

Fingerprint

atmospheric models
photometry
stars
hydrodynamics
metallicity
atmosphere
luminosity
color
atmospheres
radii
star distribution
curves
atmospheric model
parameter
astrophysics
method
temperature
approximation
excitation

Keywords

  • Hydrodynamics
  • Stars: atmospheres
  • Stars: fundamental parameters
  • Stars: variables: rr lyrae

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

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title = "Fundamental parameters of rr lyrae stars from multicolour photometry and kurucz atmospheric models - III. SW and, DH peg, CU Com and DY peg",
abstract = "We report the most comprehensive UBV(RI)C observations of the bright, radially pulsating field stars SW And, DH Peg, CU Com and DY Peg. Long-term variation has been found in the ultraviolet colour curves of SW And and DH Peg. We apply our photometric-hydrodynamic method to determine the fundamental parameters of these stars: metallicity, reddening, distance, mass, radius, equilibrium luminosity and effective temperature. Our method works well for SW And, CU Com and DY Peg. A very small mass 0.26 ± 0.04 M⊙ of SW And has been found. The fundamental parameters of CU Com are those of a normal double-mode RR Lyrae (RRd) star. DY Peg has been found to have paradoxical astrophysical parameters: the metallicity, mass and period are characteristic of a high-amplitude δ Sct star while the luminosity and radius place it in the group of RR Lyrae stars. DH Peg has been found to be peculiar: the definite instability in the colour curves towards ultraviolet; the dynamical variability of the atmosphere during the shocked phases suggests that the main assumptions of our photometric-hydrodynamic method, the quasi-static atmosphere approximation (QSAA) and the exclusive excitation of radial modes are probably not satisfied in this star. The fundamental parameters of all stars studied in this series of papers are summarized in tabular and graphical form.",
keywords = "Hydrodynamics, Stars: atmospheres, Stars: fundamental parameters, Stars: variables: rr lyrae",
author = "S. Barcza and J. Benkő",
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AU - Barcza, S.

AU - Benkő, J.

PY - 2014

Y1 - 2014

N2 - We report the most comprehensive UBV(RI)C observations of the bright, radially pulsating field stars SW And, DH Peg, CU Com and DY Peg. Long-term variation has been found in the ultraviolet colour curves of SW And and DH Peg. We apply our photometric-hydrodynamic method to determine the fundamental parameters of these stars: metallicity, reddening, distance, mass, radius, equilibrium luminosity and effective temperature. Our method works well for SW And, CU Com and DY Peg. A very small mass 0.26 ± 0.04 M⊙ of SW And has been found. The fundamental parameters of CU Com are those of a normal double-mode RR Lyrae (RRd) star. DY Peg has been found to have paradoxical astrophysical parameters: the metallicity, mass and period are characteristic of a high-amplitude δ Sct star while the luminosity and radius place it in the group of RR Lyrae stars. DH Peg has been found to be peculiar: the definite instability in the colour curves towards ultraviolet; the dynamical variability of the atmosphere during the shocked phases suggests that the main assumptions of our photometric-hydrodynamic method, the quasi-static atmosphere approximation (QSAA) and the exclusive excitation of radial modes are probably not satisfied in this star. The fundamental parameters of all stars studied in this series of papers are summarized in tabular and graphical form.

AB - We report the most comprehensive UBV(RI)C observations of the bright, radially pulsating field stars SW And, DH Peg, CU Com and DY Peg. Long-term variation has been found in the ultraviolet colour curves of SW And and DH Peg. We apply our photometric-hydrodynamic method to determine the fundamental parameters of these stars: metallicity, reddening, distance, mass, radius, equilibrium luminosity and effective temperature. Our method works well for SW And, CU Com and DY Peg. A very small mass 0.26 ± 0.04 M⊙ of SW And has been found. The fundamental parameters of CU Com are those of a normal double-mode RR Lyrae (RRd) star. DY Peg has been found to have paradoxical astrophysical parameters: the metallicity, mass and period are characteristic of a high-amplitude δ Sct star while the luminosity and radius place it in the group of RR Lyrae stars. DH Peg has been found to be peculiar: the definite instability in the colour curves towards ultraviolet; the dynamical variability of the atmosphere during the shocked phases suggests that the main assumptions of our photometric-hydrodynamic method, the quasi-static atmosphere approximation (QSAA) and the exclusive excitation of radial modes are probably not satisfied in this star. The fundamental parameters of all stars studied in this series of papers are summarized in tabular and graphical form.

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KW - Stars: variables: rr lyrae

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