منابع مشابه
The Absolute Magnitude of Rr Lyrae
We derive the absolute magnitude of RR Lyrae stars by two independent maximum-likelihood estimations , using Hipparcos proper motion and par-allax data, respectively. By applying the statistical parallax method to 99 Halo RR Lyrae stars, we obtain the mean absolute magnitude < M V > = 0:69 0:10 at ={1.58. Independently of this method, we furthermore derive the M V { Fe/H] relation from H...
متن کاملRr Lyrae – Theory Vs Observation
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...
متن کاملStrange Cepheids and Rr Lyrae
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 (...
متن کاملThe Rr Lyrae Distance Scale
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....
متن کاملOn Metallicity And RR Lyrae Light Curves
Fourier decompositions are performed for the light curves of six RRab and 3 RRc field stars. These are added to previous work to form a sample of 61 RRab and 12 RRc pulsators. The RRab stars are divided into two groups-a short-period (SP) group with P < 0~575 and a long-period (LP) group with P > 0~575. The Fourier phase parameter CP21 is found to fall off very regularly with decreasing metalli...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1973
ISSN: 0074-1809
DOI: 10.1017/s0074180900055017