Origin of Irregularities in RR Lyrae Pulsations
نویسندگان
چکیده
منابع مشابه
Irregularities in atmospheric pulsations of RR Lyrae stars
From high spectral resolution observations of the Fe II line at 4923.921Å, it is shown that the star RR Lyrae shows significant differences, both in radial velocity and in line FWHM, from one pulsation cycle to the next. Two explanations are discussed. The first one is the multiperiodic character of the pulsation (Blazhko effect) which was recently detected (Chadid et al. 1999). In this case, t...
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Fourier decomposition is employed to compare the light curves of RR Lyrae stars with those emerging from hydrodynamic models. Very good agreement is obtained between theory and observation for the RRc stars, but in the case of the RRab stars there are significant discrepancies in the Fourier phase quantities 4>21 and 4>31' The deficiencies of the models are not remedied by replacing Carson opac...
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The luminosities, effective temperatures and metallicities that are derived empirically by Kovács and Jurcsik from the light curves of a large number of globular cluster and field RRab and RRc stars are compared to theoretical RR Lyrae models. The strong luminosity dependence of the empirical blue and red edges (LogL vs. LogTeff diagram) is in disagreement with that of both radiative and convec...
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Strange modes can occur in radiative classical Cepheids and RR Lyrae models. These are vibrational modes that are trapped near the surface as a result of a ’potential barrier’ caused by the sharp hydrogen partial ionization region. Typically the modal number of the strange mode falls between the 7th and 12th overtone, depending on the astrophysical parameters of the equilibrium stellar models (...
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We review seven methods of measuring the absolute magnitude M V of RR Lyrae stars in light of the Hipparcos mission and other recent developments. We focus on identifying possible systematic errors and rank the methods by relative immunity to such errors. For the three most robust methods, statistical parallax, trigonometric parallax, and cluster kinemat-ics, we find M V (at [Fe/H]= −1.6) of 0....
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 2000
ISSN: 0252-9211
DOI: 10.1017/s0252921100057821