老无所依——这个星球上的最后一位目视彗星猎手——记美国当代目视寻彗大王唐纳德·麦克霍尔兹

彗星猎手专题本专题文字和照片版权经受访者授权未经允许不得转载小序重新翻开几个月前采访麦克霍尔兹先生的访问记录,我思索了很久,却依然不知该如何下笔。直到我发现了本文题记中麦克霍尔兹先生所说的那句话,我的内心才     

Low-dispersion spectra of six Me stars

Low-dispersion spectra are presented for six Me stars. No. 1 may be a new Mira variable. Emission line data and spectral types are given for No. 3 (probably SW Cam) and No. 5 (SV Leo).     

十颗Me星的低色散光谱

本文给出十颗Me星的低色散光谱资料,其中有六颗星以前没有人给出发射线资料,四颗前人没有给出光谱资料;还有一颗是新发现的Me星。这里我们均给出发射线资料及光谱型。另外还给出了每颗星的光谱描迹图及其中三颗星的证认图。     

In ISM Modeling, The Devil is in the Details: You Show Me Your OVI and I’ll Show You Mine

The three sections of this paperillustrate the importance of rationalizing ISMtheory and modeling with the observational information.     

Magnetic Activity and the Interaction Between the Stellar Magnetosphere and the Accretion Disk

Analytical and numerical analysis of the interaction between the magnetosphere of the Pre-Main-Sequence (PMS) stars and accretion disks are converging to a robust, fundamental mechanism for jet formation. They provide a reasonably solid base-line to explain the current observations on the formation of solar-like stars. In this summary, the connection between observations and this paradigm are reviewed critically and some observational tests proposed.     

Fractal turbulence and the origin of the galaxies and of the large-scale structure

Observations show that the geometry of the large-scale distribution of galaxies is like a self-similar sponge which can be regarded as a fractal in fractal geometry (the Sierpinski sponge) with the fractal dimensionD _f=3–, =1.7–1.8 is the index in the two-point correlation function.We suggest using a new scheme to explain the origin of galaxies and large-scale structure. In our model, we assume that the density perturbations in the early Universe are adiabatic, and once they come within the horizon, they might produce the vortices of the fractal turbulence because of the Thomson drag. A model of the fractal turbulence is also given in this paper. The results obtained show that the basic characteristics of the galaxies (massM _g, angular momentumJ _g) and the large-scale structure (fractal dimensionD _f) can be explained, if the spectrum of early perturbations is the scale-free Zeldovich spectrum.     

依巴谷星表和第谷星表的特征和意义

主要论述依巴谷星表和第谷星表的观测特征和天体测量特征,依巴谷卫星在短期内同时测定大量高精度的恒星位置,自行和视差等五个天体测量参数以及星等和色指数,依巴谷星表和第谷星表为建立高精度的光学参考系,为研究恒星的起源,演化,分布,质量,大小和光度等,为研究双星和聚星的分布和运动,为研究星系运动和星系动力学提供了大量的高精度资料,具有重要的科学意义。     

Hypothesis of variable g and the secular accelerations of the Sun and the Moon

It is known that the observed secular accelerations of the Sun and Moon are not consistent with the tidal interactions of the Earth with the Sun and Moon. Following Dicke, the hypothesis of variable constant of gravity is adopted and expressions for the accelerations are derived. It is shown that if the theoretical ratio of the acceleration is equated the observed one, a unique value for —/G can be calculated. Adopting the accelerations obtained by Fotheringham, Newton, Muller and Stephenson, and Stephenson, it is found that — /G ranges from 1.4 × 10^–11 to 3.3 × 10^–11 yr^–1. This estimate is consistent with the one based upon the comparison of the lunar accelerations measured with respect to atomic and ephemis times.     

Heating and reconnection of the emerging magnetic flux-tubes and the role of the interchange instability

We propose in the present paper that the basic behaviors of newly-emerged magnetic regions (NEMR) as seen in EUV and soft X-rays from space are interpreted by the interchange instability of the magnetic field of NEMR in the global situation surrounding it.It is shown that the situation with the NEMR is unstable against the interchange instability, and a continual relaxation to the lower energy state, or a continual invasion of the magnetic flux of the NEMR to the ambient region in the form of fine bundles or thin sheets, will take place in a short time scale of ₁ L/V _A following the change in the boundary condition at the photosphere. The second and the final relaxation is shown to be the enhanced Joule dissipation in a time scale of hours to several days occurring in the thin current sheets on the interface of this intermingled structure which is distributed in a large volume. This hypothesis may provide an explanation for the heating of NEMR to an X-ray emitting temperature, which is otherwise rather difficult to explain. The observed fast reconnection without appreciable flares (except for some smaller brightenings) is another aspect which can be explained in the present hypothesis. Namely, since the situation with the NEMR is unstable for the interchange from the beginning, the stressed configuration is relaxed before storing appreciable energy in the form of magnetic stress and therefore without a drastic release of a large amount of stored stress energy in the form of a flare.     

Influence of the Earth on the background and the sensitivity of the GRM and ECLAIRs instruments aboard the Chinese-French mission SVOM

SVOM (Space-based multi-band astronomical Variable Object Monitor) is a future Chinese-French satellite mission which is dedicated to Gamma-Ray Burst (GRB) studies. Its anti-solar pointing strategy makes the Earth cross the field of view of its payload every orbit. In this paper, we present the variations of the gamma-ray background of the two high energy instruments aboard SVOM, the Gamma-Ray Monitor (GRM) and ECLAIRs, as a function of the Earth position. We conclude with an estimate of the Earth influence on their sensitivity and their GRB detection capability.     

On the relation between the ERP and the rotation vector

This paper deals with the Earth Rotation Parameters (ERP), and presents a formula to calculate the rotation vector.