共查询到20条相似文献，搜索用时 31 毫秒
1.
Astronomy Letters - Calculations of stellar evolution up to the early white dwarf stage were carried out for stars with mass on the main sequence $$M_{0}=0.82$$ , $$0.85$$ , $$0.9M_{\odot}$$ and... 相似文献
2.
Modes of nonradial oscillations of six composite polytropic models have been investigated numerically to study the effect of central condensation parameter
being the density at the centre and
the mean density of a stellar model) on the modes of nonradial oscillations of stellar models. 相似文献
3.
Astronomy Letters - The mode switching in Cepheids is studied using the methods of the nonlinear theory of stellar pulsation, depending on the main sequence mass $$M_{0}$$ and the abundance of... 相似文献
4.
The synchronization between the orbital motion and axial rotation of the two component stars of a binary system is reviewed.
Some previous published papers are mentioned and the general conclusion is outlined: If we shall use a rotating coordinate
system synchronous with one of the two stellar axial rotations, it is not possible to obtain a Jacobi integral and the Roche
geometry cannot be further analyzed. In addition, a theoretical approach is summarized in order to use the axial rotations
of the two component stars, even if the constants of the stellar structure (k2)1, (k2)2must be taken into consideration. So it is found that if the stellar angular velocities are higher than the corresponding
Keplerian angular velocity (ωi≫ ωk, i=
), the problem of the rotational effect could be of practical consideration. Finally, a theoretical relationship between the
two constants (k2)1and (k2)2of the stellar structure is established. 相似文献
5.
A solution of the transfer equation for coherent scattering in stellar atmosphere with Planck's function as a nonlinear function of optical depth, viz., $$B_v (T) = b_0 + b_1 {\text{ }}e^{ - \beta \tau } $$ is obtained by the method of discrete ordinates originally due to Chandrasekhar. 相似文献
6.
A solution of the transfer equation for coherent scattering in stellar atmosphere with Planck's function as a nonlinear function of optical depth, viz. $$B{\text{ }}_v (T) = b_0 + b_1 {\text{ }}e^{ - \beta \tau } $$ is obtained by the method developed by Busbridge (1953). 相似文献
7.
An approximate solution of the transfer equation for coherent scattering in stellar atmospheres with Planck's function as a nonlinear function of optical depth, viz., $$B_v \left( T \right) = b_0 + b_1 e^{ - \beta \tau } $$ is obtained by Eddington's method. is obtained by Eddington's method. 相似文献
8.
An exact solution of the transfer equation for coherent scattering in stellar atmospheres with Planck's function as a nonlinear function of optical depth, of the form $$B_v (T) = b_0 + b_1 {\text{ }}e^{ - \beta \tau } $$ is obtained by the method of the Laplace transform and Wiener-Hopf technique. 相似文献
9.
M. S. Vardya 《Astrophysics and Space Science》1984,107(1):141-153
An attempt has been made to obtain an expression for the rate of stellar mass loss using dimensional analysis. The best expression for O and B stars is of the form: $$\dot M = A'{\text{ }}\left( {\frac{1}{{G^{1/2} c^4 }}} \right){\text{ }}L^{\text{2}} {\text{ (}}R/M)^{{\text{3/2}}} .$$ It is also found thatA′ increases as one goes from B→O stars and from O→O(f)→O(f)), but is not sensitive to luminosity. 相似文献
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Effects of the grain shape on circumstellar dust dynamics and polarization of stellar radiation are analyzed. The grains are
modeled by rotating prolate and oblate spheroids.
It is shown that an asymmetry of the geometry of light scattering by non-spherical particles results in a component of the
radiation pressure
force perpendicular to the wave-vector of incident light. For silicate spheroids, this component can exceed 20 % of
. For small metallic grains, the radiation pressure force for a spheroid can be 5–10 times greater than that for a sphere
of the same volume.
A simple light scattering consideration demonstrates that the distinction in the scattering geometry of aligned non-spherical
grains can explain the observed wavelength variations of the positional angle of polarization.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
13.
Philip Chang 《Monthly notices of the Royal Astronomical Society》2009,393(1):224-228
I examine the effectiveness of Kozai oscillations in the centres of galaxies and in particular the Galactic Centre (GC) using standard techniques from celestial mechanics. In particular, I study the effects of a stellar bulge potential and general relativity on Kozai oscillations, which are induced by stellar discs. Löckmann et al. recently suggested that Kozai oscillations induced by the two young massive stellar discs in the GC drive the orbits of the young stars to large eccentricity ( e ≈ 1) . If some of these young eccentric stars are in binaries, they would be disrupted near pericentre, leaving one star in a tight orbit around the central supermassive black hole and producing the S-star population. I find that the spherical stellar bulge suppresses Kozai oscillations, when its enclosed mass inside a test body is of the order of the mass in the stellar disc(s). Since the stellar bulge in the GC is much larger than the stellar discs, Kozai oscillations due to the stellar discs are likely suppressed. Whether Kozai oscillations are induced from other non-spherical components to the potential (e.g. a flattened stellar bulge) is yet to be determined. 相似文献
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Using the kinematical data we try to solve the Jeans equation to provide mass estimation of the globular cluster M4. The proper
motion data provides two independent velocity dispersion profiles which we need in this estimation. Moreover, we have calculated
the density distribution function and checked the anisotropy of the velocity dispersion.
The comparison of the dynamical mass with the estimation stellar mass for M4 gives the best estimation of the mass inside
a spherical shell centered on the cluster, with a radius corresponding to 840 arcsec on the sky, as 4-5× 104 M
.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
Xin-Fa Deng 《Astronomy Letters》2015,41(6):252-259
In this work, I examine the environmental dependence of galaxy age, stellar velocity dispersion and stellar mass in the LOWZ sample of the Sloan Digital Sky Survey Data Release 10 (SDSS DR10). I measure the projected local density Σ5, divide the LOWZ sample into subsamples with a redshift binning size of Δz = 0.02 and analyze the environmental dependence of galaxy age, stellar velocity dispersion and stellar mass in each redshift bin. It is found that galaxy age, stellar velocity dispersion and stellar mass in the LOWZ galaxy sample are very weakly correlatedwith the local environment, like the one in theCMASS galaxy sample does. 相似文献
18.
In order to obtain the internal structure of a main-sequence star such as the Sun usually one has to solve the detailed structure equations numerically. This paper is an attempt to construct analytic models for the stellar nuclear energy generation. We give closed-form analytic results for the stellar luminosity and stellar neutrino emission rate when the radial matter density of the spherical star under consideration is linear. For the numerical estimation of the neutrino flux of a specified stellar nuclear reaction we take into account parameters of the standard solar model. The present paper gives for the first time the connection between stellar structure parameters and neutrino fluxes in an analytic stellar model. 相似文献
19.
We have analyzed the formation, structure, and dynamical evolution of the population of stars that escaped from open clusters by numerical simulations using S. Aarseth’s modified NBODY6 code. In the Galactic tidal field, the population of stars that escaped from a cluster is shown to be elongated along the orbit of the cluster symmetrically about its core in the form of stellar tails of increasing sizes. We analyze the parameters of stellar tails as a function of such initial simulation conditions as the number of stars, the cluster density, the eccentricity of the Galactic cluster orbit in the plane of the Galactic disk, and the z velocity component. As a result, we constructed a grid of model stellar tails of open clusters. The grid includes such time-dependent parameters of the stellar tails as the length, the cross section, the number of stars, the velocity distribution, etc. Our simulations allow us to clarify the origin of moving clusters and stellar streams and to assess the role of star clusters in forming the stellar velocity field in the solar neighborhood. 相似文献
20.
We have investigated the stellar population properties in the central regions of a sample of lenticular galaxies with bars
and single-exponential outer stellar disks using the data from the SAURON integral-field spectrograph retrieved from the open
Isaac Newton Group Archive. We have detected chemically decoupled compact stellar nuclei with a metallicity twice that of
the stellar population in the bulges in seven of the eight galaxies. A starburst is currently going on at the center of the
eighth galaxy and we have failed to determine the stellar population properties from its spectrum. The mean stellar ages in
the chemically decoupled nuclei found range from 1 to 11 Gyr. The scenarios for the origin of both decoupled nuclei and lenticular
galaxies as a whole are discussed. 相似文献