REGIONAL VARIATIONS IN DENOMINATIONAL SWITCHING AMONG WHITE PROTESTANTS*     

Roger W. Stump 《The Professional geographer》1987,39(4):438-449

This study examines the hypothesis that the determinants of denominational switching vary regionally among white American Protestants. Data for the analysis are taken from the National Opinion Research Center's General Social Survey for 1974 through 1984. Using logistic regression, the analysis compares the determinants of switching among respondents residing in the nine Census regions of the U.S. Results reveal significant regional differences in the determinants of switching, especially in the effects of conversion, childhood affiliation and interdenominational marriage.  相似文献   

White dwarfs: Recent developments     

D. Koester 《Astronomy and Astrophysics Review》2002,11(1):33-66

Summary. During the last decade white dwarfs have become important as tools in many areas beyond traditional stellar physics: from the age determination of the stars in the solar neighborhood to the dating of open clusters and the distance determination of globular clusters. They are primary candidates for the MACHO microlensing events, possibly for a stellar component of the dark halo, and for the supernova Ia progenitors. The recent developments in these areas are reviewed, but some highlights from more “mature” areas such as stellar parameters, mass distributions, magnetic, and pulsating white dwarfs are also summarized briefly. Received 5 October 2001 / Published online 11 January 2002  相似文献   

White dwarf stars as strange quark matter detectors – II     

O. G. Benvenuto † 《Monthly notices of the Royal Astronomical Society》2006,368(2):553-562

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Non-Radial Pulsations in Components of Symbiotic Stars     

N. I. Bondar  V. V. ProkofÉva 《Astrophysics and Space Science》2005,296(1-4):161-164

Photometric observations of symbiotic stars in the blue and in the red spectral regions make it possible to reveal non-radial oscillations both of the cool and of the hot components. Light variations of red giants in the symbiotic systems CI Cyg and AG Peg show several periods in the 10–80^d range, interpreted as p-mode pulsations. These modes are excited by a bright spot produced by radiation flux from the hot component. The spot moves on the red giant’s photosphere at a velocity close to the sound speed. During the active phase of the symbiotic star CH Cyg, at least 25 frequencies of oscillations in the 150–6000 s range of periods were found in the light of the white dwarf. Their features correspond to non-radial g-modes. In the frame of 2D gas dynamical non-adiabatic models, the interaction between gas flows and the accretion disk leads to formation of a system of shock waves propagating towards the compact object, which is one of possible mechanisms to excite non-radial pulsations of white dwarfs in symbiotic systems.  相似文献   

Short-period AM CVn systems as optical, X-ray and gravitational-wave sources   总被引：1，自引：0，他引：1  

G. Nelemans  L. R. Yungelson  S. F. Portegies Zwart 《Monthly notices of the Royal Astronomical Society》2004,349(1):181-192

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Discovery of irradiation-induced variations in the light curve of the classical nova V2275 Cyg (N Cyg 2001 No. 2)     

&#;. Balman  A. Y&#;lmaz  A. Retter  T. Saygaç  H. Esenoglu 《Monthly notices of the Royal Astronomical Society》2005,356(2):773-777

We present charge-coupled device (CCD) photometry, light curve and time-series analysis of the classical nova V2275 Cyg (N Cyg 2001 No. 2). The source was observed for 14 nights in total in 2002 and 2003 using an R filter with the 1.5-m Russian–Turkish joint telescope (RTT150) at the TUBITAK National Observatory in Antalya, Turkey, as part of a large programme on the CCD photometry of cataclysmic variables. We report the detection of two distinct periodicities in the light curve of the nova: (a)   P ₁= 0.314 49(15) d [7.6 h]  , and (b)   P ₂= 0.017 079(17) d [24.6 min]  . The first period is evident in both 2002 and 2003 whereas the second period is only detected in the 2003 data set. We interpret the first period as the orbital period of the system and attribute the orbital variations to aspect changes of the secondary irradiated by the hot white dwarf (WD). We suggest that the nova was a supersoft X-ray source in 2002 and, perhaps, in 2003. The second period could be a quasi-periodic oscillation originating from the oscillation of the ionization front (due to a hot WD) below the inner Lagrange point or a beat frequency in the system as a result of the magnetic nature of the WD if steady accretion has already been re-established.  相似文献   

Kappa-mechanism excitation of retrograde mixed modes in rotating B-type stars     

R. H. D. Townsend 《Monthly notices of the Royal Astronomical Society》2005,364(2):573-582

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A source of high-velocity white dwarfs     

Melvyn B. Davies  rew King  Hans Ritter 《Monthly notices of the Royal Astronomical Society》2002,333(2):463-468

We investigate whether the recently observed population of high-velocity white dwarfs can be derived from a population of binaries residing initially within the thin disc of the Galaxy. In particular, we consider binaries where the primary is sufficiently massive to explode as a Type II supernova. A large fraction of such binaries are broken up when the primary then explodes as a supernova, owing to the combined effects of the mass loss from the primary and the kick received by the neutron star on its formation. For binaries where the primary evolves to fill its Roche lobe, mass transfer from the primary leads to the onset of a common envelope phase during which the secondary and the core of the primary spiral together as the envelope is ejected. Such binaries are the progenitors of X-ray binaries if they are not broken up when the primary explodes. For those systems that are broken up, a large number of the secondaries receive kick velocities ∼100–200 km s⁻¹ and subsequently evolve into white dwarfs. We compute trajectories within the Galactic potential for this population of stars and relate the birth rate of these stars over the entire Galaxy to those seen locally with high velocities relative to the local standard of rest (LSR) . We show that for a reasonable set of assumptions concerning the Galactic supernova rate and the binary population, our model produces a local number density of high-velocity white dwarfs compatible with that inferred from observations. We therefore propose that a population of white dwarfs originating in the thin disc may make a significant contribution to the observed population of high-velocity white dwarfs.  相似文献   

White dwarf envelopes: further results of a non-local model of convection     

M. H. Montgomery  F. Kupka 《Monthly notices of the Royal Astronomical Society》2004,350(1):267-276

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Imaging planets around nearby white dwarfs     

M. R.Burleigh  F. J.Clarke  S. T.Hodgkin 《Monthly notices of the Royal Astronomical Society》2002,331(4):L41-L45

We suggest that Jovian planets will survive the late stages of stellar evolution, and that white dwarfs will retain planetary systems in wide orbits (≳5 au). Utilizing evolutionary models for Jovian planets, we show that infrared imaging with 8-m class telescopes of suitable nearby white dwarfs should allow us to resolve and detect companions ≳3 M _JUP. Detection of massive planetary companions to nearby white dwarfs would prove that such objects can survive the final stages of stellar evolution, place constraints on the frequency of main-sequence stars with planetary systems dynamically similar to our own and allow direct spectroscopic investigation of their composition and structure.  相似文献