太阳二维光谱观测研究的进展和展望

论述了太阳二维光谱观测和研究的重大意义，综述了二维光谱观测技术和仪器的进展，特别介绍了应用ＣＣＤ的成像光谱仪的最近发展。文中还介绍了近年来二维光谱观测研究所取得的一些新结果，展望了未来观测技术和课题研究的发展前景。     

The researches at torino on wide double stars

Summary The present poster shows the main researches conduced at the Astronomical Observatory of Torino during this last decade in the field of the wide double stars. From the observational point of view, two different photographic techniques carried out with our 105 cm astrometric reflector over a selected sample of wide binaries are explained. With reference to the Hipparcos mission, we show two aspects of our collaboration with the INCA and FAST Consortiums. From the statistical point of view, a study concerning the systematic and accidental errors detected in visual double star observations is explained. We conclude the poster with the future foreseen researches concerning new observational techniques and new theoretical statistical studies on these wide objects.     

Collision Probability for Earth-Crossing Asteroids Using Orbital Ranging

We introduce new techniques for the computation of the collision probability for Earth-crossing asteroids in the case of short observational arcs and/or small numbers of observations. The techniques rely on the orbital element probability density computed using statistical orbital ranging. We apply the techniques to the Earth-crossing asteroid 1998 OX₄with non-vanishing collision probability in numerous close approaches after the year 2012 (inclusive). We study the invariance of the collision probability in transformations between different orbital element sets, and develop a Spearman rank correlation measure for the validity of the linear approximation. We introduce an optimized, fast version of the statistical ranging method.     

Possible Alternatives to the Supermassive Black Hole at the Galactic Center

Now there are two basic observational techniques to investigate a gravitational potential at the Galactic Center, namely, (a) monitoring the orbits of bright stars near the Galactic Center to reconstruct a gravitational potential; (b) measuring the size and shape of shadows around black hole giving an alternative possibility to evaluate black hole parameters in mm-band with VLBI-technique. At the moment, one can use a small relativistic correction approach for stellar orbit analysis (however, in the future the approximation will not be precise enough due to enormous progress of observational facilities) while for smallest structure analysis in VLBI observations one really needs a strong gravitational field approximation. We discuss results of observations, their conventional interpretations, tensions between observations and models and possible hints for a new physics from the observational data and tensions between observations and interpretations. We discuss an opportunity to use a Schwarzschild metric for data interpretation or we have to use more exotic models such as Reissner–Nordstrom or Schwarzschild–de-Sitter metrics for better fits.     

Imaging the surface of Mercury using ground-based telescopes

We describe and compare two methods of short-exposure, high-definition ground-based imaging of the planet Mercury. Two teams have recorded images of Mercury on different dates, from different locations, and with different observational and data reduction techniques. Both groups have achieved spatial resolutions of <250 km, and the same albedo features and contrast levels appear where the two datasets overlap (longitudes 270–360°). Dark albedo regions appear as mare and correlate well with smooth terrain radar signatures. Bright albedo features agree optically, but less well with radar data. Such confirmations of state-of-the-art optical techniques introduce a new era of ground-based exploration of Mercury's surface and its atmosphere. They offer opportunities for synergistic, cooperative observations before and during the upcoming Messenger and BepiColombo missions to Mercury.     

Fundamental coordinate ties using laser ranging data

One of the main goals of fundamental astronomy is to allow us to locate ourselves accurately in space and time. Each observational technique cannot supply all of the answers all of the time, and the joining of results from different techniques requires a true understanding of the particular reference frame which underlies each one. In this paper we try to state the present situation in our attempts to tie artificial satellite and lunar laser ranging data through the construction of stations designed to make both kinds of observations. This type of development strengthens both data types and eases their combination with other data types.     

Molecular Line Emission from Accretion Disks Around YSOs

In this work, we model the expected molecular emission from protoplanetary disks, modifying different physical parameters, such as dust grain size, mass accretion rate, viscosity, and disk radius, to obtain observational signatures in these sources. Having in mind possible future observations, we study correlations between physical parameters and observational characteristics. Our aim is to determine the kind of observations that will allow us to extract information about the physical parameters of disks. We also present prospects for molecular line observations of protoplanetary disks, using millimeter and submillimeter interferometers (e.g., SMA or ALMA), based on our results.     

海潮模型的比较及海潮对地球自转变化的影响

近年来,由于卫星测高工作的开展,提供了丰富准确的观测资料,产生出许多新的海潮模型。这些海潮模型的相互比较为研究海洋的精细结构、海潮的动力学、地球动力学提供了依据。另一方面,由现代空间技术和新方法来监测地球自转中的高频变化研究领域也有长足的进展。用这些技术可检测出地球自转中的周日和半日变化,从而激发地球自转的变化。一般来说,海潮影响地球自转的高频变化有两种不同的激发机制。地球的惯性张量的变化即质量项     

Can late-type active stars be explained by a dipole magnetic trap?

In this paper we review four different types of X-ray and/or radio observations of active late-type stars. We then consider if a single magnetic source configuration – a toroidal dipole magnetic trap – can possibly explain these various different observations. We conclude that, indeed, dipole magnetic confinement (similar to the magnetic configurations of the Earth's radiation belts and the case of Jupiter and the Io torus) can explain all the diverse observational data. We take this to be very strong observational support for this type of magnetic confinement scheme. We also consider that this magnetic configuration is only likely to be established and maintained in the most active stars.     

Small-scale magnetic field diagnostics outside sunspots: Comparison of different methods

We analyse different observational data related to the problem of intrinsic magnetic field strength in small-scale fluxtubes outside sunspots. We conclude that the kG range of fluxtube fields follows from not only classical line ratio method, but also from other old and new techniques. For the quiet regions on the Sun, the most probable mode of such fields has a magnetic field strength of 1.2–1.5 kG assuming the rectangular field profile. To best interpret the observations, a weak background field between fluxtubes should be assumed, and its magnetic field strength is expected to increase with the filling factor of fluxtubes. The alternative point of view about subkilogauss fluxtube fields is critically examined, and possible sources of different conclusions are presented.     

利用长期资料改进双星轨道解的一种方法

早期的地面观测积累了大量关于双星系统的观测资料.相对于近年来的各种观测数据,这些资料兼有精度低的缺陷和时间跨度长的优势．针对同时具有长期资料和依巴谷观测数据的较长周期的双星系统(如依巴谷星表的双星和多星附表中的G型双星系统),提出一种联合拟合方法,即首先通过拟合依巴谷的观测数据IAD寻求目标函数局部极小的轨道解,然后从中选出长期资料的最优解．结合这种方法的可行性分析,讨论了适用该方法的双星系统的轨道特征．作为应用实例,研究了文献中存在两种轨道解且仅有7次长期资料可以利用的系统73Leo,通过伴星质量的外符合分析,给出了具有较高可信度的轨道解．     

A search for posteclipse brightening of Io in 1973. II

Four eclipse reappearances of Io were observed with an area-scanning photometer during the 1973 apparition of Jupiter. The results of these observations and of the ones reported in the preceding paper are discussed in the context of recent physical models for posteclipse brightening. An evaluation of the relative merits and deficiencies of all observational techniques which have been used to search for posteclipse brightening of Io leads to the conclusion that the reality of this phenomenon remains very much in doubt.     

Current problems of dynamics of moons of planets and binary asteroids based on observations

The general approach to studying the dynamics of moons of planets and asteroids consists in developing more and more accurate models of motion based on observational data. Not only the necessary ephemerides, but also some physical parameters of planets and moons are obtained this way. It is demonstrated in the present study that progress in this field is driven not only by the increase in accuracy of observations. The accuracy of ephemerides may be increased by expanding the observation time interval. Several problems arise on the way toward this goal. Some of them become apparent only when the procedure of observational data processing and use is examined in detail. The method used to derive astrometric data by processing the results of photometric observations of mutual occultations and eclipses of planetary moons is explained below. The primary contribution to the error of astrometric results is produced by the unaccounted noise level in photometric readings and the inaccuracy of received values of the albedo of moons. It is demonstrated that the current methods do not allow one to eliminate the noise completely. Extensive additional photometric measurements should be performed at different angles of rotation of moons and in different spectral bands of the visible wavelength range in order to obtain correct values of the albedo of moons. Many new distant moons of the major planets have been discovered in the early 21st century. However, the observations of these moons are scarce and were performed over short time intervals; as a result, some of the moons were lost. The necessity of further observations of these Solar System bodies is pointed out in the present study. Insufficient knowledge of asteroid masses is an obstacle to improving the accuracy of the ephemerides of Mars. The basic method for determining the masses of large asteroids consists in analyzing their influence on the motion of Mars, the Earth, and spacecraft. The masses of more than 100 large asteroids were determined this way. One of the principal techniques for Earth-based measurement of the masses of asteroids involves astrometric observations of binary asteroids. The determination of relative coordinates is made rather difficult by the apparent proximity of components. The success of these efforts depends on the availability of instrumentation and the expertise of observers skilled in adaptive optics and speckle interferometry. Collaboration between different research teams and observers is absolutely necessary.     

Active galactic nuclei: what’s in a name?

Active galactic nuclei (AGN) are energetic astrophysical sources powered by accretion onto supermassive black holes in galaxies, and present unique observational signatures that cover the full electromagnetic spectrum over more than twenty orders of magnitude in frequency. The rich phenomenology of AGN has resulted in a large number of different “flavours” in the literature that now comprise a complex and confusing AGN “zoo”. It is increasingly clear that these classifications are only partially related to intrinsic differences between AGN and primarily reflect variations in a relatively small number of astrophysical parameters as well the method by which each class of AGN is selected. Taken together, observations in different electromagnetic bands as well as variations over time provide complementary windows on the physics of different sub-structures in the AGN. In this review, we present an overview of AGN multi-wavelength properties with the aim of painting their “big picture” through observations in each electromagnetic band from radio to \(\gamma \)-rays as well as AGN variability. We address what we can learn from each observational method, the impact of selection effects, the physics behind the emission at each wavelength, and the potential for future studies. To conclude, we use these observations to piece together the basic architecture of AGN, discuss our current understanding of unification models, and highlight some open questions that present opportunities for future observational and theoretical progress.     

High-redshift objects as probes of nearby cosmic voids

We show that present day observational techniques make it possible to detect diffuse gas masses down to ～10¹⁰ M _⊙ in cosmic voids with linear sizes of ～1 Mpc or larger. The observations consist of searches for absorption lines, similar in character to those produced in galactic interstellar clouds, in the spectra of high-redshift objects located beyond previously identified voids adjoining nearby superclusters.     

Technique of polarimetric observations of faint objects at the 6-m BTA telescope

We describe the technique of spectropolarimetric observations allowing for the measurements of the Stokes parameters in one of the observational modes of the SCORPIO focal reducer of the 6-m BTA telescope of the SAO RAS. The characteristics of the instrument in the spectropolarimetric mode of observations are given. We present the algorithm of observational data reduction. The capabilities of the SCORPIO spectropolarimetric mode are demonstrated on the examples of observations of various astronomical objects.     

The absolute spectrophotometric catalog by Anita Cochran

The absolute spectrophotometric catalog by Anita Cochran is presented in a machine-readable form. The catalog systematizes observations acquired at the McDonald Observatory in 1977–1978. The data are compared with other sources, in particular, the calculated broadband stellar magnitudes are compared with photometric observations by other authors, to show that the observational data given in the catalog are reliable and suitable for a variety of applications. Observations of variable stars of different types make Cochran’s catalog especially valuable.     

OSCILLATIONS IN QUIESCENT SOLAR PROMINENCES OBSERVATIONS AND THEORY – (Invited Review)

An extensive observational background about the existence of oscillations in quiescent solar prominences has been gathered during the last twenty years. From these observations, information about different oscillatory parameters such as period, wavelength, phase speed, damping time, etc., has been obtained. This observational background, combined with a growing number of theoretical studies about magneto-hydrodynamic waves in prominences, should allow the development of prominence seismology which, following helioseismology's approach, seeks to infer the internal structure and properties of solar prominences. The most recent observational and theoretical developments on prominence oscillations are reviewed here, with an emphasis on the aspects suitable to develop an observation versus theory feedback, but also pointing out key topics which should be the subject of future research for a further advancement of this field.     

International program of observations of selected minor planets: first results

International programs of observations of selected minor planets have lasted about 50 years and the last one comes to the end in 2000. The main aim of these observational programs consists in obtaining the orientation of the stellar reference frame with respect to the dynamical one using observations of the bright minor planets. The observations are also useful for the orbital improvements of the asteroids themselves. They are available from the author via e-mail at the address .During the above mentioned period more than 23 000 observations of minor planets, referred to different reference star catalogues, have been obtained. The reduction procedure of observations to the PPM star catalogue is described. The orientation parameters are given and discussed.