HD 172189, a Cluster Member Binary System with a δ Scuti Component in the Field of View of COROT

Photometric and spectroscopic results for the star HD 172189, member of the open cluster IC 4756 in the summer field of the space mission COROT, are presented. From photometric observations in the Strömgren system carried out at various epochs, its binary nature as well as the presence of a δ Scuti-type pulsating component have been discovered. The frequency analysis of the whole dataset confirms a dominant frequency of 19.5974 c d^?1 with a maximum amplitude near 0.02 mag plus other frequencies in the range 18–20 c d^?1. A preliminary orbital solution from the light curve and from four FEROS spectra reveals two similar components of around 1.5 M _⊙ orbiting with a period of 5.702 d.     

Sociological Profile of Astronomers in Spain

In this paper the main findings are presented of a recent study made by a team of sociologists from the University of Granada on the professional astronomers currently working in Spain. Despite the peculiarities of this group – its youth, twentyfold increase in size over the last 20 years, and extremely high rate of specialization abroad – in comparison with other Spanish professionals, this is the first time that the sociological characteristics of the group have been studied discretely. The most significant results of the study are presented in the following sections. Section 1 gives a brief historical background of the development of Astronomy in Spain. Section 2 analyzes the socio-demographic profile of Spanish Astronomy professionals (sex, age, marital status, etc.). Sections 3–5 are devoted to the college education and study programs followed by Spanish astronomers, focusing on the features and evaluations of the training received, and pre- and postdoctoral study trips made to research centers abroad. The results for the latter clearly show the importance that Spanish astronomers place on having experience abroad. Special attention is paid to scientific papers published as a result of joint research projects carried out with colleagues from centers abroad as a result of these study trips. Section 6 describes the situation of Astronomy professionals within the Spanish job market, the different positions available and the time taken to find a job after graduation. Section 7 examines Astronomy as a discipline in Spain, including the astronomers' own opinions of the social status of the discipline within Spanish society. Particular attention is paid to how Spanish astronomers view the status of Astronomy in Spain in comparison with that of other European countries. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cold Dust and Very Cold Excess Emission in the Galaxy

We provide insight in the origin of the far-IR to mm emission from galaxies by presenting a decomposition of the Galaxy emission where we separate the contributions from dust in the atomic gas and dust associated with quiescent molecular gas as a function of Galacto-centric distance. This decomposition leaves a puzzling very cold emission excess with a brightness independent of Galactic longitude that might be pointing at interstellar matter in the outer Galaxy not traced by H I nor CO emission. This revised version was published online in September 2006 with corrections to the Cover Date.     

Evolution of the Rotational State of Irregular Cometary Nuclei

A simplified thermal model has been used to calculate thenon-gravitational forces acting on small irregular nuclei in the orbit ofComet 46P/Wirtanen. The torque of thenon-gravitational force has beencalculated and the Euler equations have been solved in order toinvestigate the rotational evolution of several irregular nuclei duringa single orbital step. Several initial spin axis orientations andactivity patterns on their surfaces have been considered. The nucleiconsidered have a mean radius of 1 km and their inertia moments havebeen calculated assuming a homogeneous bulk density of 500 kg/m³. Inall the simulations, the initial spin period is 6h and the nucleiinitially rotate around their shortest axis. Under these assumptions,significant changes in the angular momentum and in spin period have beenobtained in all the simulations, but the nucleus is found to practicallyremain in its spin state of lowest energy during the entire orbitalperiod.     

Modelling the transport of sediment discharged by Colombian rivers to the southern Caribbean Sea

Ocean Dynamics - The three-dimensional transport of sediments released by the main rivers in the Colombian Caribbean basin is investigated using numerical model simulations. Different types of...     

龙马溪—五峰组富有机质页岩三维岩石物理模板分析及"甜点"预测

为识别四川盆地丁山区龙马溪—五峰组目的层富含页岩气的"甜点区",本文对页岩的有机碳含量、脆性、孔隙度及微裂隙等核心指标进行分析研究.对页岩展开岩石物性特征和岩石物理分析,结果显示"甜点区"具有TOC含量高、高孔隙度、低密度、脆性高(石英含量高)的特点,此外储层的拉梅常数和密度的乘积λρ分布范围是18～30 GPa·g·cm-3,泊松比v范围是0.18～0.22,剪切模量μ范围是13～18 GPa.根据储层的岩石物理特征,同时考虑孔隙度、裂隙纵横比和矿物组分对优质页岩敏感弹性参数的影响,采用等效嵌入体应力平均(EIAS)理论模型构建适合页岩气储层的三维岩石物理模板,进而预测储层的孔隙度、裂隙纵横比和石英矿物含量.基于测井数据,对构建的三维岩石物理模板进行校正,将校正后的模板应用到研究工区,选取过三口井的二维测线和三维区块,进行孔隙度、裂隙纵横比和石英矿物含量的定量预测.对比实际资料分析得出的优质页岩储层孔隙度预测范围与测井结果吻合较好,过三口井的目的层产气情况与预测结果一致性良好,目的层页岩具有高孔隙度、低裂隙纵横比和高石英含量的特征,可有效地指示优质页岩储层分布.