在Cepheus E中C^18O（J=1—0）分子外流的不准直性和速度成分

分析ＣｅｐｈｅｕｓＥ中Ｃ＾１８Ｏ（Ｊ＝１－０）的速度位置图,发现相对于峰速度的红速移度成分主要分布在中心位置附近的核区,而相对于峰速度的蓝移速度成分除了分布在中心位置附近的核区外,还可以在向东和向西北方向的外流中找到。这说明强度分布图中的分子外流的不准直分布是由相对于峰速度的蓝移速度成分的不准直分布所引起的。     

在CepheusE中C^18O（J=1—0）分子外流的不准直分布的研究

从在CepheusE中C18O（J＝1－0）的谱线频谱图发现,相对于峰速度的蓝移成分的积分流量密度明显大于相对于红移成分的积分流量密度．从在它的强度分布图也可以发现强度分布轮廓向西北和向东延伸．为此,研究了在CepheusE中C18O（J＝1－0）的速度分段积分等高图,发现相对于峰速度的蓝移速度分段积分等高图中的C18O（J＝1－0）的积分强度,要大于相对于红移速度分段积分等高图中的C18O（J＝1－0）的积分强度,同时强度分布图中的分子外流的不准直分布是由相对于峰速度的蓝移成分的分布的不准直性所引起的．     

OH17．7－20的拱星OH脉泽辐射的观测

本文作者用澳大利亚Ｐａｒｋｅｓ６４ｍ射电望远镜观测了ＯＨ１７．７－２．０的拱星ＯＨ脉泽辐射。在观测中共测得了三个峰，其中一个峰是我们新发现的弱源，两个峰是过去发现的强源。用二维Ｇａｕｓｓｉａｎ拟合我们发现强源位置与一个ＩＲＡＳ点源位置相一致，弱源位置在这个ＩＲＡＳ点源位置的西南方。强源的两个峰的速度位置和峰值流量密度都是比较稳定的。     

高准直双极分子外流速度的“哈勃”律

在高准许直双极分子外流中，气体速度和离中心恒星距离的“哈勃”关系，可能是分子外流物理性质中最关键的特征。高速喷流驱动弓激波的方式能够解释这种速度结构。本建立起一组喷射角可变的微分方程组。用数值方法得出分子外流的速度结构，这些结构非常类似于观测结果。     

OMC--3的13CO(1--0)和C18O(1--0)分子辐射

利用紫金山天文台青海站的 １３．７ ｍ毫米波望远镜,对 Ｏｒｉｏｎ Ａ分子云中的 ＯＭＣ－３区域,进行了较高分辨率的１３ＣＯ（Ｊ＝１－０）和Ｃ１８Ｏ（Ｊ＝１－０）分子辐射的成图观测．给出了该分子云中１３ＣＯ和 Ｃ１８Ｏ云核分布的整体结构和平均物理参数．观测发现,该分子云的１３ＣＯ和 Ｃ１８Ｏ的云核中心分别与最年轻的天体－Ｃｌａｓｓ ０类源 ＭＭＳＩ, ＭＭＳ４,ＭＭＳ６和ＭＭＳ７,ＭＭＳ８;ＭＭＳ９成协．此外,通过分析ＯＭＣ－３整个区域的速度场结构,发现沿 Ｃ１８Ｏ和１３ＣＯ云核方向从南到北有一个～ １．７ｋｍ／ｓ的速度场梯度,而分子云的红、蓝移团块则分别趋于云的北部和南部．并对ＯＭＣ－３区的恒星形成特征进行了讨论．     

Cepheus C的C^18O（J=1—0）分子的多核结构

利用日本名古屋大学天体物理系的毫米波射电望远镜对Cepheus C的C^18O(J=1-0）分子辐射进行了观测,得到了它相对于中心位置的B南北偏差固定的速度位置图。从本文所给出的速度位置图中,经过分析我们得到了多核结构的不同速度分布。     

1997年3月9日的日冕偏振CCD观测

给出１９９７年３月９日日全食时所作的日冕偏振ＣＣＤ观测资料的处理结果,包括太阳赤道东西和两极等十二个方向的中冕（１．６－３．２Ｒ）绝对亮度分布和偏振度分布。     

1997年3月9日日全食8.6mm波段射电观测

１９９７年３月９日日全食８．６ｍｍ波段射电观测资料的分析表明：８．６ｍｍ波段射电太阳的半径为１．０１２Ｒ,总流量为２５４０ｓｆｕ（１ｓｆｕ＝１０－２２Ｗ／ｍ２Ｈｚ）,日面平均亮温度为９６３２Ｋ,径向亮温度分布,在日面光学边缘内侧０．９３６－０．９９２Ｒ处,存在临边增亮,平均增亮幅度相对于日面中心为９．７％．     

红外源IRAS 05437-0001和IRAS 05351+3549的CO分子谱线观测研究

利用紫金山天文台青海观测站13.7米射电望远镜对红外源IRAS05437-0001和IRAS05351+3549附近区域进行了CO(J=1-0)的分子谱线观测.发现在这两个源的方向都有很强的CO发射,CO谱线还有明显的线翼成分,这暗示两个红外源存在分子外流.同时还获得了每个源5＇×5＇的成图.通过对高速气体的空间分布的观测和分析,认为这两个源为分子外流源.其中IRAS05437-0001附近区域的外流结构比较复杂,可能这一区域的外流是多极的.IRAS05351+3549附近的外流结构较简单.从两个源的红外光谱分类以及外流的动力学时标得出都是年轻星(年龄～105yrs).通过对这两个外流源的参数估算,得出两个外流源的质量损失率.     

在NGC205中发现的一颗新星

１９９７年１１月２１日在作超新星巡天时,在仙女座星系ＮＧＣ２５０中发现了一颗新星。它的光谱中有强的巴尔末线,Ｆｅｉｉ,ＨｅＩ和ＯＩ等发现线。谱线的蓝移与ＮＧＣ２５０的近似;根据ＮＧＣ２０５的距离模数得到的其极大附近时的绝对星等为－６．３,是典型的新星在极大附近的光度值,可以肯定发生在ＮＧＣ２０５中。光谱显示它是铁属新星。     

Near-infrared integral field spectroscopy of the Homunculus nebula around η Carinae using Gemini/cirpass

This work presents the first integral field spectroscopy of the Homunculus nebula around η Carinae in the near-infrared spectral region ( J band). We confirmed the presence of a hole on the polar region of each lobe, as indicated by previous near-IR long-slit spectra and mid-IR images. The holes can be described as a cylinder of height (i.e. the thickness of the lobe) and diameter of 6.5 and  6.0 × 10¹⁶  cm, respectively. We also mapped the blue-shifted component of He  i  λ10830 seen towards the NW lobe. Contrary to previous works, we suggested that this blue-shifted component is not related to the Paddle but it is indeed in the equatorial disc.
We confirmed the claim of N. Smith and showed that the spatial extent of the Little Homunculus matches remarkably well the radio continuum emission at 3 cm, indicating that the Little Homunculus can be regarded as a small H  ii region. Therefore, we used the optically thin 1.3 mm radio flux to derive a lower limit for the number of Lyman-continuum photons of the central source in η Car. In the context of a binary system, and assuming that the ionizing flux comes entirely from the hot companion star, the lower limit for its spectral type and luminosity class ranges from O5.5  iii to O7  i . Moreover, we showed that the radio peak at 1.7 arcsec NW from the central star is in the same line-of-sight of the 'Sr-filament' but they are obviously spatially separated, while the blue-shifted component of He  i λ10830 may be related to the radio peak and can be explained by the ultraviolet radiation from the companion star.     

A study of the maser source NML CYG

In analysing Masheder's observations of the OH 1612 MHz maser source in the direction of NML Cyg, I introduce a new idea, namely that the red-shifted and blue-shifted components originate in different shells of the circumstellar envelope. A self-consistent picture of velocity field, mass loss rate, coherent length and pumping mechanism is then obtainable which agrees with all the observations. The SiO non-maser emission appears to be a good indicator of the radial velocity of the central star and the velocity field of the envelope.     

Amplification of stellar background by circumstellar masers

The calculations with the use of simple maser model show that the stellar background contributes negligibly to the mean peak intensities at 1612 MHz. Under some conditions, however, the contribution from the central star may constitute a few percent of the mean peak intensity. Such possibility may occur when the thick and large OH envelope is illuminated by very luminous and extended central star. To compare the theoretical results with observations a sample of 55 OH/IR stars with best known parameters is analyzed. The ratio of the blue-shifted to the red-shifted 1612 MHz peak slightly increases in objects with the largest OH radii. This relation is interpreted in terms of amplification of the stellar photons.     

3-D radiative line transfer for be star envelopes

Based on numerical three-dimensional radiative line transfer calculations H emission line profiles of circumstellar Be star envelopes have been derived. The results show that the socalled winebottle-type emission line profiles can be explained by the combination of rotational broadening and non-coherent scattering in optically thick Keplerian disks. In a further calculation the stellar wind model of Be star envelopes has been re-investigated assuming an additional expansion component in the velocity field. The resulting asymmetric winebottle-type profiles and asymmetric shell-type emission lines with blue-shifted central depressions are in contradiction with the observed line shapes. It is concluded that isotropic stationary outflows are not suitable to explain observed asymmetric emission line profiles of Be stars.     

Key Properties of Solar Chromospheric Line Formation Process

The distribution or wavelength-dependence of the formation regions of frequently used solar lines, Hα，Hβ，CaIIH and CaII8542,in quiet Sun,faint and bright flares is explored in the unpolarized case.We stress four aspects characterising the property of line formation process:1) width of line formation core;2) line formation region;3)influence of the temperature minimum region; and 4) wavelength ranges within which one can obtain pure chromospheric and photospheric filtergrams.It is shown that the above four aspects depend strongly on the atmospheric physical condition and the lines used. The formation regions of all the wavelength points within a line may be continuously distributed over one depth domain or discretely distributed because of no contribution coming from the temperature minimum region, an important domain in the solar atmosphere that determines the distribution pattern of escape photons. On the other hand, the formation region of one wavelength point may cover only one height range or spread over two domains which are separated again by the temperature minimum region. Different lines may form in different regions in the quiet Sun. However, these line formation regions become closer in solar flaring regions. Finally, though the stratification of line-of-sight velocity can alter the position of the line formation core within the line band and result in the asymmetry of the line formation core about the shifted line center, it can only lead to negligible changes in the line formation region or the line formation core width. All these results can be instructive to solar filtering observations.     

A fluid dynamical flow model for the central peak in the rotation curve of disk galaxies

The rotation curve of the central region in some disk galaxies shows a linear rise, terminating at a peak (primary peak) which is then followed by a deep minimum. The curve then again rises to another peak at more or less half-way across the galactic radius. This latter peak is considered as the peak of the rotation curve in all large-scale analysis of galactic structure. The primary peak is usually ignored for the purpose. In this work an attempt has been made to look at the primary peak as the manifestation of the post-explosion flow pattern of gas in the deep central region of galaxies. Solving hydrodynamical equations of motion, a flow model has been derived which imitates very closely the actually observed linear rotational velocity, followed by the falling branch of the curve to minimum. The theoretical flow model has been compared with observed results for nine galaxies. The agreement obtained is extremely encouraging. The distance of the primary peak from the galactic centre has been shown to be correlated with the angular velocity in the linear part of the rotation curve. Here also, agreement is very good between theoretical and observed results. It is concluded that the distance of the primary peak from the centre not only speaks of the time that has elapsed since the explosion occurred in the nucleus, it also speaks of the potential capability of the nucleus of the galaxy for repeating explosions through some efficient process of mass replenishment at the core.     

Stochastic and dynamic temperature changes in the interplanetary gas

Exact solutions have been found to the Fokker-Planck equations, incorporating stochastic velocity changes and modelling particles moving in an inverse square central force field under an inverse square collision frequency. The solutions for the velocity distribution contain a combination of collisional and dynamical (reversible) heating. At a general position, there are two populations each with three distinct temperatures, one normal to the orbital plane and the others closely parallel and perpendicular to the mean orbit. Collisional heating is strong and most readily detected in the secondary component of gas which reaches upstream directions along indirect orbits (attractive central force). For interplanetary helium gas reaching 1 a.u., the collisional heating ranges from effective transverse increase of 200 K and radial increase of 1500 K in the downstream wake, to several thousand K increase in radial temperature of the secondary component transverse to the initial gas stream. In interpreting 584 Å sky background radiation observations, the dynamical changes in the velocity spread have to be taken into account for helium gas that is initially hot, when Doppler shifts relative to the solar emission line are significant; the present solutions being the thermal approximations to the distribution function reveal the appropriate radial temperature as a function of space.     

Can elliptical galaxies be equilibrium systems?

This paper deals with the question of whether elliptical galaxies can be considered as equilibrium systems (i.e., the gravitational+centrifugal potential is constant on the external surface). We find that equilibrium models such as Emden-Chandrasekhar polytropes and Roche polytropes withn=0 can account for the main part of observations relative to the ratio of maximum rotational velocity to central velocity dispersion in, elliptical systems. More complex models involving, for example, massive halos could lead to a more complete agreement. Models that are a good fit to the observed data are characterized by an inner component (where most of the mass is concentrated) and a low-density outer component. A comparison is performed between some theoretical density distributions and the density distribution observed by Younget al. (1978) in NGC 4473, but a number of limitations must be adopted. Alternative models, such as triaxial oblate non-equilibrium configurations with coaxial shells, involve a number of problems which are briefly discussed. We conclude that spheroidal oblate models describing elliptical glaxies cannot be ruled out until new analyses relative to more refined theoretical equilibrium models (involving, for example, massive halos) and more detailed observations are performed.