有核多层球密度分布的严格解

本文在文献[4]的基础上重新较详细地讨论了有核结构球对称体系中物质的分布,严格地求解了Euler方程,得到了广义相对论有核结构的多层球的解析解。结果表明,在广义相对论的有核多层球结构下,物质的密度分布将与半径的三次方成反比(n∝r~(-3)),而不是与r的二次方成反比(n∝r~(-2)),因此通过观测可以与等温聚集核(n～r~(-2))的情况相区别。     

广义相对论中静态荷电球体的内解

本文在假设荷电球体内部物质密度为ρ_m=μγ~α,电荷密度为ρ_e=ρ_0γ~(b_e-λ/2)的情况下,严格求解Einstein-Maxwell场方程,求得了静态荷电球体的一个较为普遍的内部解。这个解可以看作是Wyman得到的内部解推广到荷电情况下的结果,并且将Wilson,李鉴增,Santos,Pant和Sah等人给出的许多结果作为自己的特例包括在内。     

非平衡热力学中恒星结构稳定性的研究——Ⅲ.质量耗损情况下的PPI反应

恒星是开放系统.本文以非线性非平衡热力学中超熵产生判据来研究质量耗损(dρ/dt=- ε/c~2,ρ为总质量密度,ε为单位体积的产能率,c为光速)下,PPI反应所决定的太阳型恒星结构的稳定性问题。结果表明:时,恒星结构肯定稳定.式中X、Y分别为氢、氦丰度,A_1、A_3分别为H~1和H_e~3的原子量,β～10~(-4)—10~(-5)(当8×10~6K≤T≤1.5×10~7K时),(ρ_1为H’的质量密度),(N_A为阿佛伽德罗常数,Q_1=-1.442 MeV,Q_2=5.493 MeV,Q_3=12.859 MeV).     

一般三体问题在不变平面上的Hill零速度线

本文利用文[1]给出的不等式(1),详细讨论了在各种E,C下一般三体问题在不变平面上的Hill零速度线随尺度ρ的振动情况。     

研究高密物质的平均场方法的改进

本文对以前提出的改进的平均场模型(简称 MMFT)做了进一步的讨论。发现该模型有新的解 ml=2 ; 加入ρ介子,计算了核物质对称能 α_4;用新的参数计算了加ρ与未加ρ的中子物质的态方程,将二者作了比较,并与ml=4.3的结果做了比较;引用二体关联函数对矢量介子平均场的形式做了初步的理论探讨;用中子星结构方程计算了相应于各种态方程的中子星最大质量,结果是: MMFT-2(ml=2): M_(max)=2.22M(不含ρ介子) M_(max)=2.27M(加入ρ介子) MMFT-1(ml=4.3):M_(max)=1.69M(不含ρ介子) M_(max)=1.89M(加入ρ介子)     

密近双星动力学的几个问题

本文用一种比较简单的方法导出了食双星的轨道周期和恒星周期间的关系式,指出Kopal在文[1]推导中忽略r~2/h摄动变化的不合理性.本文还讨论了考虑形状摄动的密近双星系统的一种简单模型,推出了求解该模型平动解的方程;同时针对扁率因子β_1、β_2为小量的特点,提出了两种求解直线平动解的方法.     

恒星内部核素~(56)Fe、~(56)Co、~(56)Ni和~(56)Mn电子俘获过程中微子能量损失高斯修正

采用高斯修正法,研究了核素~(56)Fe、~(56)Co、~(56)Ni和~(56)Mn电子俘获过程中微子能量损失.结果表明:对核素的Gamow-Teller(G-T)共振跃迁能级分布的高斯修正使中微子能量损失率增加.在低能跃迁电子俘获过程为主导地位的反应中,高斯修正对中微子能量损失的影响很小,而对高能G-T共振跃迁为主要的电子俘获过程的中微子能量损失的影响将大大增加.如核素~(56)Fe在密度ρ_7=100(ρ_7以10~7 mol·cm~(-3)为单位),高斯函数半宽度△=14.3,18.3,22.3 Mev时,修正差异大约达2个数量级,核素~(56)Ni在△=6.3,18.3Mev差异分别达60%和40%.     

Abell团相关性-富度关系的统计研究

本文对D≤4,R≥0的Abell团样品和整个R≥3的Abell团样品的空间两点相关函数做了统计分析,结果表明R≥0,R=0和R≥3的Abell团的相关函数分别为175r~(-1.8),150r~(-1.8)和1900r~(-1.8)利用已有的R≥1和R≥2团的相关函数的统计结果,我们得到了Abell团的相关性幅度α与富度N之间的关系:α∝N~(1.6)。在相关性幅度的统计误差所允许的范围内,α与N之间的关系可以在宇宙弦理论中得到解释。     

半简并费密子自引力系统的平衡位形

本文讨论半简并费密子自引力系统的平衡位形,将基于热力学量级数展开的计算结果与直接计算Fermi积分得到的精确值作了对比,指出了级数展开法的适用范围。对温度T不为零的任何值,不论中心密度如何,远离中心处的密度总是按r~(-2)降低,位形的质量和半径总是无限的。     

狐狸座BW星的周期分析

利用文[1]中权重5的大量高精度测光数据,用文[2]中的周期分析法,得出BWVul的主要脉动周期P_1=0.21010425d。另有变幅仅为前者十分之一的二倍频P_2=0.10052300d及四倍频P_4=0.05026096d。文[3]求出的变幅更小的P_3、P_5、P_6、P_7、P_8等倍频可信度很低。故多重周期不是引起P_1长期变化及限制脉动变幅的主因。     

A method of measuring the [α/Fe] ratios from the spectra of the LAMOST survey

The [α/Fe] ratios in stars are good tracers to probe the formation history of stellar populations and the chemical evolution of the Galaxy. The spectroscopic survey of LAMOST provides a good opportunity to determine [α/Fe] of millions of stars in the Galaxy. We present a method of measuring the [α/Fe]ratios from LAMOST spectra using the template-matching technique of the LSP3 pipeline. We use three test samples of stars selected from the ELODIE and MILES libraries, as well as the LEGUE survey to validate our method. Based on the test results, we conclude that our method is valid for measuring [α/Fe]from low-resolution spectra acquired by the LAMOST survey. Within the range of the stellar parameters Teff= [5000, 7500] K, log g = [1.0, 5.0] dex and [Fe/H]= [onsistent with values derived from high-resolution spectra,-1.5, +0.5] dex, our [α/Fe] measurements are c and the accuracy of our [α/Fe] measurements from LAMOST spectra is better than 0.1 dex with spectral signal-to-noise higher than 20.     

类星体QSO2000-330的重元素吸收线系统的证认

本文利用文[1]和文[2]所给出的高红移类星体吸收系统的证认方法,对目前最大红移类星体QS02000-330(z_e=3.78)的吸收光谱进行了吸收线红移系统的证认,并得到了六个重元素的吸收线系统:z_a=3.1881,3.1913,3.3335,3.5519以及z_a=1.3441,3.3459。前四个系统和Hunstead等人(1986)所得到的A、B、C、D系统(红移值分别是z_a=3.1881,3.1914,3.3332,3.5519)相符合;后两个是我们新发现的吸收系统。     

VZ Cnc的光电测光及其周期变化

本文给出自1962年到1980年之间九个夜晚对VZ Cnc观测获得的光电测光资料,并利用迄今已收集到的136个极大光度发生时刻,讨论了该星的周期变化,得β=1/p dp/dt=-[1.1±0.2]×10~(-7)/年。指出文[4]中的UBV数据可靠性有问题。     

A search for Mg-poor stars using LAMOST survey data

Most Galactic metal-poor stars exhibit enhanced α-abundances(e.g.[Mg/Fe] ～ +0.4) according to previous studies of stellar chemical compositions.However, a handful of metal-poor stars with large deficiencies in Mg(e.g. [Mg/Fe]～-0.2) show severe departures from this α-enhancement trend. The sub-solar[Mg/Fe] ratios of these anomalous stars indicate that they possess different chemical enrichment histories than the majority of Galactic metal-poor stars. In previous work,we presented a method to select Mg-poor metal-poor stars from low-resolution SDSS spectra based on a spectral matching technique. In this paper, a similar method is applied to low-resolution(R ～ 1800) LAMOST spectra. Stellar [Mg/Fe] abundances are determined by using stellar parameters delivered by the LAMOST Data Release2 catalog. From a sample of ～ 60 000 stars with atmospheric parameters in the range Teff = [5500, 6500] K and [Fe/H] = [-2.4, +0.5], we select 15 candidate Mg-poor metal-poor stars.     

SDSSJ022119.84＋005628.4： A Radio-Loud Narrow-LineSeyfert 1 Galaxy with Star Formation in its Nucleus

The optical spectrum of SDSS J022119.84 + 005628.4 (R. A. = 02h 21m 19.84s, Dec = 00°56' 28.4", J2000; z = 0.399785 ± 0.000558) is analyzed by multi-component profile modelling. The small flux ratio of [OⅢ]NC/Hβ (=0.78) and FWHM(HβBC) = 1778.1 ±85.9 km s-1 led us to identify SDSS J022119.84 + 005628.4 as a Narrow-line Seyfert 1 galaxy with RFe= 1.4-1.0+1.0 and intermediate radio loudness, logR = 1.93. The continuum low jump at the Balmer limit might be contributed by a starburst component, which suggests that the object is a relatively young AGN with star-formation activity in its inner region. This provides a useful observational test of the AGN evolution. The low flux ratio of the narrow components, [OⅢ]/Hβ = 1.62, and the prominent [OⅡ]γ3727 emission, [OⅡ]/[OⅢ] = 2.24, suggests that there should be a group of AGNs different from Seyfert 2s when their broad line regions are obscured by the torus on the line of sight. A possible orientation effect is suggested to interpret the observed Seyf     

中红外波段星系电离特性研究

中红外高电离发射线[OⅣ](25.9μm)的产生机制尚不明确。利用简单的光致电离模型,Hao等人(2009)初步分析发现,当星暴星系模型给出的[NeⅢ]/[NeⅡ]值与观测相当时,其给出的[OⅣ]/[SⅢ]值却比观测值低约4个量级。[OⅣ]/[SⅢ],[SⅣ]/[SⅢ],[NeⅢ]/[NeⅡ]等中红外发射谱线比值及其变化趋势,以及其与ITERA package中提供的各类更新的光致电离模型的比较,是进一步探索星暴星系中[OⅣ]发射来源的一种有效途径。观测数据与电离模型计算结果的比较表明,Hao等人(2009)中提出的中红外发射线诊断图[OⅣ]/[SⅢ]对[SⅣ]/[SⅢ]中的分支结构能分别较好地与AGN与星暴星系光致电离模型相吻合。这些星暴星系模型所产生的[OⅣ]发射的强度与电离光谱中大于4 Ryd段的相对光子流量呈紧密正相关,单独考虑Wolfe-Rayet星的辐射对电离光谱的贡献足以解释星暴星系中的[OⅣ]发射线;而对于[OⅣ]/[SⅢ]对[NeⅢ]/[NeⅡ]诊断图,模型仍很难解释观测结果,特别是星暴星系分支:当由模型计算出的[OⅣ]/[SⅢ]值与观测相当时,其给出的[NeⅢ]/[NeⅡ]值相比于观测仍明显偏高。如果考虑上述发射线均来自具有单一密度与电离参数的发射区,那么[NeⅢ]/[NeⅡ]值与电离光谱21.6～41.0 eV段的斜率密切相关。     

旋涡星系的厚度的估算

本文利用文[1]中所求得的扰动引力势的严格解,当此解由无旋臂区向有旋臂区连续过渡时,在解中出现一非波动项,对此项作出估计,可得出厚度(H=2/α)与开始形成旋臂处的半径的r_0关系:αr_0=7(α为星系半厚度的倒数).我们由[2]选出了50颗旋涡星系,并测定了它们的r_0,由此定出了星系盘的平均厚度.     

Vector Magnetic Field Measurement of NOAA AR 10197

A set of two-dimensional Stokes spectral data of NOAA AR 10197 obtained by the Solar Stokes Spectral Telescope (S3T) at the Yunnan Observatory are qualitatively analyzed. The three components of the vector magnetic field, the strength H, inclinationγand azimuth X, are derived. Based on the three components, we contour the distributions of the longitudinal magnetic field and transverse magnetic field. The active region (AR) has two different magnetic polarities apparent in the longitudinal magnetic map due to projection effect. There is a basic agreement on the longitudinal magnetic fields between the S3T and SOHO/MDI magnetograms, with a correlation coefficientρBl = 0.911. The transverse magnetic field of the AR has a radial distribution from a center located in the southwest of the AR. It is also found that the transverse magnetic fields obtained by Huairou Solar Observing Station (HRSOS) have a similar radial distribution. The distributions of transverse magnetic field obtained by S3T and HRSOS have correlation coefficients,ρAzimu = 0.86 andρBt = 0.883, in regard to the azimuthal angle and intensity.     

ISO SWS Spectroscopy of WR 146 (WC6+O)

We have obtained ISO SWS spectroscopy of WR 146 (WC6+O) covering the wavelength range 2.6-20 μm. WC6 wind emission is observed in numerous lines of He II and C IV, as well as in the [Ne III] 15.5 μm line, but not in [Ne II] 12.81 or [Ne V] 14.32 μm. An analysis of these spectra (and complementary radio and optical data) yields for the WC6 star: v∞ = 2700 km s-1; M=2.6×10-5M⊙yr-1; C/He = 0.15; and a neon abundance bound of 3.4×10-3≤Ne/He≤6.8×10-3. The neon abundance is close to that predicted in stellar evolution models of WC stars. This revised version was published online in August 2006 with corrections to the Cover Date.     

Chemical abundance analysis of 19 barium stars

We aim at deriving accurate atmospheric parameters and chemical abundances of 19 barium(Ba) stars, including both strong and mild Ba stars, based on the high signal-to-noise ratio and high resolution Echelle spectra obtained from the 2.16 m telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. The chemical abundances of the sample stars were obtained from an LTE, plane-parallel and line-blanketed atmospheric model by inputting the atmospheric parameters(effective temperatures Teff, surface gravities log g, metallicity [Fe/H] and microturbulence velocity ξt) and equivalent widths of stellar absorption lines. These samples of Ba stars are giants as indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. Their Na, Al, α- and iron-peak elements(O, Na, Mg, Al, Si, Ca,Sc, Ti, V, Cr, Mn, Ni) are similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture(n-capture) process elements relative to the Sun. Their median abundances of[Ba/Fe], [La/Fe] and [Eu/Fe] are 0.54, 0.65 and 0.40, respectively. The Y I and Zr I abundances are lower than Ba, La and Eu, but higher than the α- and iron-peak elements for the strong Ba stars and similar to the iron-peak elements for the mild stars. There exists a positive correlation between Ba intensity and [Ba/Fe].For the n-capture elements(Y, Zr, Ba, La), there is an anti-correlation between their [X/Fe] and [Fe/H]. We identify nine of our sample stars as strong Ba stars with [Ba/Fe]0.6 where seven of them have Ba intensity Ba=2-5, one has Ba=1.5 and another one has Ba=1.0. The remaining ten stars are classified as mild Ba stars with 0.17[Ba/Fe]0.54.