V2213 Cyg is a New W Uma-Type System     

Elena Pavlenko  Anna Litvinchova 《Astrophysics and Space Science》2005,296(1-4):297-300

V2213 Cyg was discovered as a variable star by Pavlenko (1999) in 1998. We present our photometry of V2213 Cyg from 1998–2003 based on CCD observations with the K-380 Cassegrain telescope of CrAO and the 60 cm Zeiss telescope of SAI. Observations have been carried out mostly in R and sometimes in B and V Johnson system. The total amount of data is 2270 points, covering ∼50 nights. We classify this binary as a W UMa-type contact system. Using all data we determined the orbital period to be 0.350079 ± 0.000007 day. The mean brightness varies between R = 14.35 and 14.05. The mean 1999–2003 orbital light curve has two humps and a primary minimum (I), which is 0.04 mag brighter than the deeper secondary one (II). The mean humps have slightly different height. The difference between two individual maxima varies within 0.1 mag, which may indicate an activity of the components. The highest hump is an asymmetrical one: it has sort of a shoulder at phases 0.75–0.80, before entering the less deep primary minimum (phase 0.0). The system is rather reddened, its colour indices are: B−V ∼ 0.8 and V−R ∼ 0.7, and give a spectral class of V2213 Cyg earlier than K.  相似文献   

A model of polarized OH maser emission in W75N     

M. D. Gray  B. Hutawarakorn  R. J. Cohen 《Monthly notices of the Royal Astronomical Society》2003,343(4):1067-1080

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Contact Binaries: A Study of the Proximity Effects and Gravity Darkening Based on Kopal’s Fourier Method     

P. G. Niarchos 《Astrophysics and Space Science》2005,296(1-4):359-370

A new method for the determination of the proximity effects and gravity darkening exponents in contact binaries of W UMa type is presented. The method is based on Kopal’s method of Fourier analysis of the light changes of eclipsing variables in the Frequency Domain. The method was applied to 36 W UMa systems for which geometric and photometric elements have been derived by the most powerful techniques. The derived values are very close to those predicted by the existing theory of radiative transfer or convective equilibrium.  相似文献   

Strong magnetic field in W75N OH maser flare     

V. I. Slysh  V. Migenes 《Monthly notices of the Royal Astronomical Society》2006,369(3):1497-1501

A flare of OH maser emission was discovered in W75N in 2000. Its location was determined with the Very Long Baseline Array (VLBA) to be within 110 au from one of the ultracompact H  ii regions, Very Large Array 2 (VLA2). The flare consisted of several maser spots. Four of the spots were found to form Zeeman pairs, all of them with a magnetic field strength of about 40 mG. This is the highest ever magnetic field strength found in OH masers, an order of magnitude higher than in typical OH masers. Three possible sources for the enhanced magnetic field are discussed: (i) the magnetic field of the exciting star dragged out by the stellar wind; (ii) the general interstellar field in the gas compressed by the magnetohydrodynamic shock; and (iii) the magnetic field of planets which orbit the exciting star and produce maser emission in gaseous envelopes.  相似文献   

藏北南羌塘盆地曲瑞恰乃地区中侏罗世色哇组、莎巧木组、布曲组的生物地层特征     

王永胜  张树岐  郑春子  李庆武  冯德臣  李学彬  于喜文 《中国区域地质》2008,(1):92-100

对藏北南羌塘盆地曲瑞恰乃地区的晚三叠世-侏罗纪地层进行了研究,自下而上划分为晚三叠世日干配错群,晚三叠世～早侏罗世索布查组,早侏罗世曲色组,中侏罗世色哇组、莎巧木组、布曲组、夏里组和晚侏罗世索瓦组。其中,对中侏罗世色哇组、莎巧木组、布曲组生物地层的研究为本文的主要内容,研究成果为该区中侏罗世地层层序的建立和详细对比提供了重要的依据。  相似文献   

A geophysical study of the granites and the sedimentary basins of the Xanthi area (N. Greece)     

G. N. Tsokas  G. C. Christofides  C. Papakonstantinou 《Pure and Applied Geophysics》1996,146(2):365-392

Intrusive features of varying size can be interpreted from the aeromagnetic map of the Xanthi area in N. Greece.The Xanthi pluton, which outcrops north of the city of Xanthi, seems to have the shape of a truncated pyramid. This feature has relatively large areal extent and reaches an approximate depth of 7 km. Another, relatively large magnetic body is buried under the sediments at the estuary of the Nestos River.3-D models of several smaller intrusions were constructed and the produced effect was compared to the observed. Some of these intrusions seem to be detached branches of the large Xanthi pluton.The basement in the outer part of the basin of the Nestos River seems to be buried at about 4 km depth. This figure is obtained by the Multiple Source Werner Deconvolution estimates and it is in agreement with the results of former geophysical studies and deep industrial boreholes.A 3-D model of the Xanthi-Komotini basin suggests that this basin is about 0.4 km deep at its southern part. The depth at its northern boundary is about 1.8 km while the boundary itself is formed by the large Kavala-Xanthi-Komotini fault.The Tertiary basin of the Nestos River and the observed magmatism are consistent with the idea of an older extensional tectonic regime in the area.  相似文献   

相律的应用:蒸发结晶过程自由度          下载免费PDF全文

房春晖  宋彭生 《盐湖研究》1993,(1)

在连续原理和浓度限制条件的基础上,分析了卤水蒸发过程的自由度,提出了“蒸发结晶过程自由度”这一概念。发现蒸发结晶过程自由度在整个过程中不是1便是0,在1和0之间交替变化,与选择的组分数和析出固相数目无关。蒸发结晶过程自由度为1,物理意义是在不引起新相产生旧相不消失的前提下过程连续地变化(水分的连续蒸失),几何意义是指在适当的坐标系中的一条线,一条直线或曲线;0的物理意义是指新相的产生和旧相的即将消失或者前一段的连续变化过渡到后一段的连续变化,几何意义是指一点,两蒸发阶段的交点或者过程的终点。简单地讨论了过程的单向性和连续件。  相似文献   

Holocene record of productivity in the NW Iberian continental shelf     

V. Alves Martins  C. Patinha  E. Ferreira da Silva  J.-M. Jouanneau  O. Weber  F. Rocha   《Journal of Geochemical Exploration》2006,88(1-3):408

A multiproxy approach (textural characteristics, heavy metal concentrations and benthic foraminifera data) was adopted to study the OMEX core KSGX 40, collected at the Galicia Mud Deposit (NW Iberian outer continental shelf) and recording the last ca. 4.8 ka cal BP. Geochemical profiles of Fe, Mn, Zn, Co, Cr, Cu, Ni, Pb, Al and Ca show significant temporal variations. Benthic foraminifera productivity proxy suggests that the recorded muddy events were contemporaneous of a higher C_org flux to the marine benthic environment. The higher flux of organic matter, following a long-term intensification of the upwelling and coinciding with a finer sedimentation, led to depressed levels of oxygen beneath the water-sediments interface and to early diagenetic processes of several redox-sensitive elements.  相似文献   

可可西里——东昆仑活动构造带强震活动研究   总被引：13，自引：0，他引：13  

张国民  田勤俭  王辉 《地学前缘》2003,10(1):39-46

青海昆仑山口西 8.1级地震发生在具有新生性特征的可可西里—东昆仑活动断裂带上。该断裂带在 190 0年以来的 10 0多年中经历了一个强震活动过程。在该强震活动过程中 ,地震沿整个可可西里—东昆仑活动构造带分段破裂 ,强震的破裂长度和震级之间大致满足对数线性的统计关系 ,强震活动呈现指数型时间分布的加速特征。这种强震加速活动特征可以用含多个震源体的孕震系统的强震成组活动模型给予解释。  相似文献   

原子荧光光谱法测定化探样品时有机质对As,Sb,Bi的干扰   总被引：1，自引：0，他引：1  

汪明启  刘应汉 《地质科技情报》2003,22(1):105-109

通过研究黑龙江省森林沼泽景观区有机水系沉积物（泥炭）、土壤中As,Sb,Bi的测定结果，发现样品中的有机质对王水消解氢化物原子荧光法测定上述元素存在极大的干扰，提出采用低温（＜450℃）灰化处理可完全消除干扰。对比研究还发现，过去森林沼泽景观区的区域化探扫面资料中的As,Sb,Bi数据存在问题，应专门对其进行评价研究。  相似文献