The EC 14026 stars -- X. A multi-site campaign on the sdBV star PG 1605+072     

D. Kilkenny  C. Koen  D. O'Donoghue  F. van Wyk  K. A. Larson  R. Shobbrook  D. J. Sullivan  M. R. Burleigh  P. D. Dobbie  S. D. Kawaler 《Monthly notices of the Royal Astronomical Society》1999,303(3):525-534

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An eclipse of the X-ray flux from the dwarf nova OY Carinae in quiescence     

Gabriel W. Pratt  B. J. M. Hassall  T. Naylor  Janet H. Wood 《Monthly notices of the Royal Astronomical Society》1999,307(2):413-419

We present a phase-resolved ROSAT HRI X-ray light curve of the dwarf nova OY Car in quiescence. The X-ray flux is eclipsed at the same time as the optical eclipse of the primary, and the region of X-ray emission is comparable in size to the white dwarf. We use subsequent optical observations to update the orbital ephemeris of the system.  相似文献   

RR Lyrae variables in M5 as a test of pulsational theory     

F. Caputo  V. Castellani  M. Marconi  V. Ripepi 《Monthly notices of the Royal Astronomical Society》1999,306(4):815-827

We present B and V CCD photometry for variables in the cluster central region, adding new data for 32 variables and giving suitable light curves, mean magnitudes and corrected colours for 17 RR Lyrae variables. Adding the data given in this paper to similar data that have already appeared in the literature, we discuss a sample of 42 variables, as given by 22 RR_ab and 20 RR_c, in the light of recent predictions from pulsational theories. We find that the observational evidence concerning M5 pulsators appears in marginal disagreement with predictions concerning the colour of the first overtone blue edge (FOBE), whereas a clear disagreement appears between the zero-age horizontal branch (ZAHB) luminosities predicted through evolutionary and pulsational theories.  相似文献   

The 1995–96 decline of R Coronae Borealis: high-resolution optical spectroscopy     

N. Kameswara Rao  David L. Lambert  Mark T. Adams  David R. Doss  Guillermo Gonzalez  Artie P. Hatzes  C. Renée James  C. M. Johns-Krull  R. Earle Luck  Gajendra Pandey  Klaus Reinsch  Jocelyn Tomkin  Vincent M. Woolf 《Monthly notices of the Royal Astronomical Society》1999,310(3):717-744

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An Algol type binary with a δ Scuti component: RZ Cassiopeiae revisited     

E. Soydugan  F. Soydugan  C. Ibanolu  A. Frasca  O. Demircan  M. C. Akan 《Astronomische Nachrichten》2006,327(9):905-911

We present new BV photometry and spectroscopic observations of RZ Cassiopeiae. The light and radial velocity curves were formed by the new observations which have been analyzed simultaneously by using theWilson‐Dewinney code. The non‐synchronous rotational velocity v ₁ sin i = 76 ± 6 km s^–1, deduced for the primary component from the new spectroscopic observations, was also incorporated in the analysis. A time‐series analysis of the residual light curves revealed the multi‐periodic pulsations of the primary component of RZ Cas. The main peak in the frequency spectrum was observed at about 64.197 c d^–1 in both B and V bands. The pulsational constant was calculated to be 0.0116 days. This value corresponds to high overtones (n ∼ 6) of non‐radial mode oscillations.We find significant changes in the pulsational amplitude of the primary component from year to year. The peak‐to‐peak pulsational amplitude of the main frequency displays a decrease from 0.^m013 in 2000 to 0.^m002 in 2001 and thereafter we have found an increase again in the amplitude to 0.^m01 in the year 2002. We propose the mass transfer from the cool secondary to the pulsating primary as a possible explanation for such remarkable changes in the pulsational behavior of the primary component. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

On‐line database of photometric observations of magnetic chemically peculiar stars     

Z. Mikul&#x;ek  J. Janík  J. Zverko  J. i&#x;ovský  M. Zejda  M. Netolický  M. Va&#x;ko 《Astronomische Nachrichten》2007,328(1):10-15

We present our extensive project of the On‐line database of photometric observations of magnetic chemically peculiar stars to collect published data of photometric observations of magnetic chemically peculiar (mCP) stars in the optical and near IR regions. Now the nascent database contains more than 107 000 photometric measurements of 102 mCP stars and will be continually supplemented with published or new photometric data on these and about 150 additional mCP stars. This report describes the structure and organization of the database. Moreover, for the all included data we estimated the error of measurements and the effective amplitudes of the light curves. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

VLA/GBI observations of the new high mass X-ray binary LS 5039     

M. Rib  J. M. Paredes  J. Martí 《New Astronomy Reviews》1999,43(8-10)

We comment on the main radio emitting properties of the proposed high mass X-ray binary LS 5039. Our study is based on multi-epoch observations with the VLA radio interferometer, at 2.0, 3.6, 6.0 and 20 cm wavelengths, as well as on the first data obtained by the GBI-NASA Monitoring Program at 3.6 and 13.3 cm wavelengths. The source appears to be compact (θ≤0′′.1) and moderately variable, with a non-thermal radio spectrum suggestive of synchrotron radiation.  相似文献   

BEAM GLOBAL MODEL FOR THE SEISMIC ANALYSIS OF RC FRAMES     

D. MIRAMONTES  O. MERABET  J. M. REYNOUARD 《地震工程与结构动力学》1996,25(7):671-688

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京津冀区域趋同的实证分析   总被引：8，自引：0，他引：8  

孙久文  邓慧慧 《地理与地理信息科学》2006,22(5):60-63

根据区域趋同基本理论,采用新古典方法,运用Barro和Sala—I—Martin趋同模型分析京津冀区域经济增长情况,进行了α趋同和β趋同检验,研究结果表明,第三产业的发展差距以及北京、天津显著的综合区位优势是造成京津冀区域趋异的主要原因。  相似文献   

TESS空间卫星单扇区变星的周期性研究          下载免费PDF全文

唐延柯  盖宁  李志凯  杨海莲  董文会 《天文学报》2021,62(4):39

TESS (Transiting Exoplanet Survey Satellite)空间卫星提供的短曝光、高精度光度测量为寻找并区分变星与搜寻行星提供了良好的数据.利用变星源的光变曲线,使用周期频谱分析与光变折叠等一系列方法分析了TESS空间卫星21扇区19995颗拥有高质量光变数据的目标源,并对这些源进行了分类,共获得4624颗变星,其中食双星322颗、脉动变星470颗、行星凌星37颗.所得变星结果与VSX (The International Variable Star Index)变星表进行了交叉比较,共交叉匹配了625颗变星源,这些交叉源中共有131颗为食双星系统、31颗为脉动变星,并通过周期频谱分析获取了双星绕转以及脉动周期.另外在59颗变星中发现明显耀发现象,交叉源中有8颗变星为行星凌星并同样通过周期频谱分析获取了行星绕转周期,从而验证了TESS空间卫星数据对变星分析的可行性.通过利用TESS空间卫星21扇区获得的变星周期结果与VSX变星表中提供的变星周期对比,发现与VSX变星表中绝大部分变星的周期一致,有一部分结果与VSX变星表中的结果差别较大,对这些变星周期结果做了进一步修正,并给出了变星表未列出的变星周期结果.  相似文献