Showing papers in "The Astrophysical Journal in 1971"
2,169 citations
1,314 citations
623 citations
TL;DR: Molecular hydrogen formation on dust grain surfaces, discussing recombination efficiency as function of surface temperature was discussed in this article, where the authors also considered recombination as a function of the surface temperature.
Abstract: Molecular hydrogen formation on dust grain surfaces, discussing recombination efficiency as function of surface temperature
561 citations
TL;DR: In this paper, the Red giant star s-process and subsequent delayed electron capture, accounting for large Li abundances, are discussed. But the authors focus on the delay of electron capture.
Abstract: Red giant star s-process and subsequent delayed electron capture, accounting for large Li abundances
527 citations
TL;DR: In this article, the radiative cooling coefficient for a low-density optically thin plasma with no molecules or dust, of cosmic abundances in the range from 10,000 to 100,000,000 K, was derived.
Abstract: The paper extends and improves the radiative cooling coefficient calculations of Cox and Tucker (1969) and Cox and Daltabuit (1971) for a low-density optically thin plasma with no molecules or dust, of cosmic abundances in the range from 10,000 to 100,000,000 K. Earlier rates applied to a plasma containing H, He, C, N, O, Ne, Mg, Si, and S; the present study added Ca, Fe, and Ni. For the elements included, many individual lines are calculated which previously has been averaged together. The cooling processes considered are permitted, forbidden, and semiforbidden line transitions, including contributions from dielectronic recombination and bremsstrahlung, radiative recombination, and two-photon continua. The ionization balance is calculated in collisional equilibrium using an approximate auto-ionization following inner-shell excitation and the low-density limit for the dielectronic recombination rate. Cooling in various observational bands in the soft X-ray region is determined.
524 citations
TL;DR: In this article, a simple steady-state solution for the outermost halo, defined as the region from which stars may escape after a few additional orbits through the central core of the system, is presented.
Abstract: The accumulation of stars in the halo of a spherical stellar system, together with the escape of stars from the system, result from stellar encounters within a dense central core. The resultant halo structure is studied both analytically and numerically for an isolated system. On the assumption that conditions in the central core remain constant with time, a simple steady-state solution is obtained for the outermost halo, or 'fringe', defined as the region from which stars may escape after a few additional orbits through the central core of the system. In this steady-state solution the density in phase space, obtained from a simple integral equation for the fringe region, is found to vary nearly linearly with the total energy of a star per unit mass for energies which are less than the energy of escape.
444 citations
TL;DR: In this article, a computer model for dynamical evolution of isolated disks of stars with initial velocity dispersions corresponding to Toomre criterion is presented, noting instability relative to large scale modes.
Abstract: Computer model for dynamical evolution of isolated disks of stars with initial velocity dispersions corresponding to Toomre criterion, noting instability relative to large scale modes
354 citations
345 citations
TL;DR: In this paper, a fluid polytrope model was used to estimate the coronal Alfven waves pressure exertion on solar wind, using one fluid polyrope model with one fluid-polytope model.
Abstract: Outwardly propagating coronal Alfven waves pressure exertion on solar wind, using one fluid polytrope model
TL;DR: Large amplitude periodic X ray pulsations from Centaurus X-3, observing abrupt source intensity and pulse rate changes as mentioned in this paper, were used to detect the presence of a nuclear power station in the X-ray channel.
Abstract: Large amplitude periodic X ray pulsations from Centaurus X-3, observing abrupt source intensity and pulse rate changes
TL;DR: Galactic magnetic field generation by dynamo process with nonuniform rotation and turbulence in gaseous disk was described in this article, where the authors proposed a dynamo-based approach to generate magnetic field.
Abstract: Galactic magnetic field generation by dynamo process with nonuniform rotation and turbulence in gaseous disk
TL;DR: In this article, the authors discuss induced electric field and Fermi mechanism for solar flare two stage particle acceleration from X-ray burst observations, and discuss the induced electric fields.
Abstract: Solar flare two stage particle acceleration from X-ray burst observations, discussing induced electric field and Fermi mechanism
TL;DR: In this paper, the authors explored the hypothesis that pulsars can produce supernova explosions of type II, with the aid of detailed hydrodynamical calculations, and presented theoretical light curves obtained from hydrodynamic calculations with radiative diffusion.
Abstract: The hypothesis, that pulsars can produce supernova explosions of type II, is explored with the aid of detailed hydrodynamical calculations. Preliminary calculations performed with Gunn (1971) indicated that the electromagnetic energy radiated by a newly formed rotating, magnetic, neutron star could drive off the remaining envelope of a red giant star for stars having initial masses in the range 3–8 M ⊙. Here we present theoretical light curves obtained from hydrodynamic calculations with radiative diffusion and compare them with observations of supernovae. For the case of a star of original mass 4.5 M ⊙,light maximum is calculated to occur when the envelope, now in the form of a thin shell, has reached a radius of 9 × 1015 cm, a velocity of 7650 km s−1 and an effective temperature of 8000 K, at which point its optical thickness approaches unity. The early part of the light curve can be strongly affected by the presence or absence of a dust-laden circumstellar envelope. The temperature, luminosity, decay rate, and envelope velocity observed in the latter phases of type II supernovae are simulated with fair accuracy by the present model.
TL;DR: In this paper, millimeter emission lines from interstellar methyl cyanide transitions, noting kinetic temperature and hydrogen density, were analyzed for the first time, and they were shown to be stable.
Abstract: Millimeter emission lines from interstellar methyl cyanide transitions, noting kinetic temperature and hydrogen density