SIMBOL-X: An hard X-ray formation flying mission

In 2004 and 2005 CNES decided to perform phase 0 studies on 4 scientific missions: ASPICS (Solar physics), MAX (γ-rays Laue lens), PEGASE (hot Jupiter study by an interferometer in the 2μm to 4.5μm range) and SIMBOL-X (hard X-rays telescope). This last mission had already undergone a feasibility study in 2003 (ref. [4]), however a complementary study was necessary to take into account the possibilities of increasing the payload mass allowance, as well as the developments in the payload design and science goals (see ref. [1]). The output of this new detailed study is described hereafter.     

射电干涉测量对天文脉泽研究的贡献

天文脉泽已成为一个迅速的研究领域，重点评述了射电干涉测量对天文脉泽观测和研究所起的作用。     

Use of Roche coordinates in the problems of small oscillations of tidally distorted stellar models

The system of Roche coordinates developed by Kopal to study the problems of stars in close binary systems has been used to study the problems of small oscillations of tidally distorted stars.     

VLF waves in the magnetosphere

The study of VLF waves at ground based stations is an important source of information on particles trapped in the magnetosphere. By various techniques it is also possible to measure plasma densities, electric fields and monitor energetic particle injection. By studying the propagation of waves beneath the ionosphere it is possible to study particle precipitation from the magnetosphere. In this paper we summarise some of the techniques and results obtained from the study of VLF waves at the South African research station in Antarctica.     

Effect of Continuum Scattering on the Statistical and Temporal Characteristics of Spectral Line Formation

Astrophysics - Some new results from our study of the effect of continuum scattering on different observed characteristics of spectral lines are presented. The main purpose is to study temporal...     

Use of Roche coordinates in the problems of small oscillations of rotationally distorted stellar models

The system of Roche coordinates developed by Kopal to study the problems of stars in close binary systems has been used to study the problems of small oscillations of rotationally distorted stars.     

An analytical averaged model of orbital resonance

After having examined the characteristics of some models used at present in the study of orbital resonance, we propose an analytical averaged model, which offers certain convenience in the study of both the characteristics and the evolution of resonance.     

SIMPLE: A High Resolution Near IR Spectrograph for the European ELT

We present the main features of SIMPLE, the Phase A study of a high resolution near IR spectrograph for the European Extreme Large Telescope and we mention a few science cases which are relevant for the study of planets in the solar system and beyond.     

The evolution from visible to infrared variable AGB stars

Results of the Vassiliadis and Wood (1993) model for the evolution on the AGB are used to study how DENIS can complement an optical and IRAS based study of Long Period Variable AGB stars in a field towards the galactic bulge.     

High Resolution Spectroscopic Campaigns to Support Spacecraft Observations of Comets with Small Telescopes

Ground based observations of comets obtained in support of spacecraft missions and space telescopes have provided critical supporting context that greatly enhances the value of the combined dataset. Major areas of ground-based contribution include providing unique instrumental capabilities and an increased temporal or global perspective on the system under study. This paper describes a decades long program of supporting cometary observations focused on high resolving power measurements of ions and atomic/molecular radicals in the coma. The instrumentation is described, along with the species under study and the results from a large campaign to study comet C/1995O1 (Hale-Bopp).     

Effect of interaction of the various modes on the radial velocity curves of the polytropic models of rotationally and tidally distorted pulsating variable stars

In our previous work, we developed a model to study the effects of rotation and/or tidal distortions on anharmonic radial oscillations and hence on the radial velocity curves of the polytropic models of pulsating variable stars.We considered the first three modes(fundamental and the next two higher modes) for the polytropic models of index 1.5 and 3.0 in that work.In the present paper, we are further extending our previous work to study the effect of the interaction of various modes on anharmonic radial oscillations and hence on radial velocity curves of the rotationally and/or tidally distorted polytropic models of pulsating variable stars.For this purpose, we have considered the following cases:(i) fundamental mode(ii) fundamental and the first mode,(iii) fundamental and the next two modes and finally(iv) fundamental and the next three higher modes of pulsation in our study.The objective of this paper is also to investigate whether the interaction of various modes affects the results of our previous study or not.The results of this study show that the interaction of the fundamental mode with higher modes appreciably changes the shape of the radial velocity curve of rotationally distorted and rotationally and tidally distorted polytropic models of pulsating variable stars.     

Effects of rotation and tidal distortions on the shapes of radial velocity curves of polytropic models of pulsating variable stars

Anharmonic oscillations of rotating stars have been studied by various authors in literature to explain the observed features of certain variable stars. However, there is no study available in literature that has discussed the combined effect of rotation and tidal distortions on the anharmonic oscillations of stars. In this paper, we have created a model to determine the effect of rotation and tidal distortions on the anharmonic radial oscillations associated with various polytropic models of pulsating variable stars. For this study we have used the theory of Rosseland to obtain the anharmonic pulsation equation for rotationally and tidally distorted polytropic models of pulsating variable stars. The main objective of this study is to investigate the effect of rotation and tidal distortions on the shapes of the radial velocity curves for rotationally and tidally distorted polytropic models of pulsating variable stars. The results of the present study show that the rotational effects cause more deviations in the shapes of radial velocity curves of pulsating variable stars as compared to tidal effects.     

Nonlinear optics in celestial natural maser-laser environment

The study of celestial (natural) maser-laser environment has not yet been well connected with nonlinear optics; many nonlinear optical processes and effects have been (fundamentally) neglected. It is now proposed in this Letter that nonlinear optics can (and should) actively be introduced to the study of the celestial maser-laser environment, with some modifications upon consideration of the difference of environments. This Letter provides a theoretical basis for this new approach. This is very significant to the study of celestial maser-laser environment, and may be significant to nonlinear optics as well; this may also produce an interplay between the two fields.     

Bounding greybody and deflection angle of improved Schwarzschild black hole

In this paper, we study the weak deflection angle in the spacetime of improved Schwarzschild black hole using the method derived by Gibbons and Werner. To do so, we derive the optical curvature from the optical metric and calculate deflection angle in weak field limits by using the Gauss–Bonnet theorem. Moreover, we study the effect of the plasma medium on the weak gravitational lensing using the Gauss–Bonnet theorem. Furthermore, we also study the graphical analysis of the deflection angle in both the plasma and non-plasma mediums. Moreover, we obtain the bound on greybody for improved Schwarzschild black hole.     

Be星的星周盘模型与Be/X射线双星系统(英)

介绍了Be星的基本特性．评述了近年来对Be星星周物质结构研究的成果．重点介绍了最新的关于Be星星周盘产生和变化的动力学模型．另外，对Be／X射线双星系统的研究也做了简要评述，重点论述了致密星与Be星延伸大气的相互作用．     

活动星系核的多波段能谱及其发射机制──Ⅱ．红外连续辐射能谱

本文讨论了１６个红外强ＰＧ类星体的红外辐射能谱。我们假设这些活动星系核的红外谱是由非热辐射机制和尘埃的热辐射共同产生的，通过对红外包的最佳拟合，我们发现大多数ＰＧ类星体的红外包位于７一２４μ的中远红外区，尘埃的热辐射机制能很好地产生观测到的红外包。通过模拟能定量地说明尘埃产生的热致辐射在这些天体的红外谱中的相对重要性，在模型与观测值之间的拟合中，我们得到了在这些天体中核加热的尘埃区的大小、尘埃的分布等模型参数。     

Tidal gravitational redshifts of spectral lines in geometrodynamics

An alternative approach is proposed for the study of the non-cosmological redshifts. The approach is based on the radiation formulation of the tidal gravitation acceleration in geometrodynamics and the spacetime curvature around the massive objects. The resulting formalism can be used to study the object mass and the gravitation magnitude from the observed spectral lines with redshifts.     

Thermonuclear burning ignition and propagation in surface layers of neutron stars. 1. General study and one-zone model without mass-flow

We develop and study a general model describing ignition and propagation of burning. It is applied to explosive thermonuclear burning in surface layers of neutron stars. For this purpose an one-zone model of a thin surface layer is developed. We study thermonuclear burning ignition and propagation along the layer with its help.     

Mira变星的有轴对称转动膨胀的拱星包层速度流场

许多Mira变星具有轴对称转动的膨胀拱星包层。因此研究有轴对称转动的膨胀拱星包层的速度流场是十分必要的。我们研究了Mira变星的有轴对称转动的膨胀的拱星包层的速度流场,得到了它的严格形式解。所得到的结果与观测给出的事实是相一致的。最后,还讨论了恒星的质量损失率。     

The Spatial Distribution of W UMa-Type Stars

The aim of this project is to study the spatial distribution of contact binaries and to compare the sample from the project of study the W UMa-type stars, with existing databases such as Hipparcos, GCVS or ASAS (ESA, 1997; GCVS, 2005; Pojmanski, 2002).