A New Martian Meteorite from Antarctica:Grove Mountains (GRV) 020090

Reported in this paper are the petrology and mineral chemistry of GRV 020090, the second Martian meteorite collected from the Grove Mountains, Antarctica. This meteorite, with a mass of 7.54 g, is completely covered by a black and glazy fusion crust. It has two distinct textural regions. The interstitial region is composed of euhedral grains of olivine, pigeonite, and anhedral interstitial maskelynite, with minor chromite, augite, phosphates and troilite. The poikilitic region consists of three clasts of pyroxenes, each of which has a pigeonite core and an augite rim. A few grains of subhedral to rounded olivine and euhedral chromite are enclosed in the pyroxene oikocrysts. GRV 020090 is classified as a new member of lherzolitic shergottites based on the modal composition and mineral chemistry. This work will shed light on the composition of Martian crust and magmatism on the Mars.

Classification of 24 New Ordinary Chondrites from the Grove Mountains, Antarctica

Petrography and mineral chemistry of 24 ordinary chondrites from the Grove Mountains, Antarctica, have been studied in order to identify their chemical-petrographic types. These samples were selected from a total of 4448 Grove Mountains (GRV) meteorites collected during the 19th Chinese Antarctic Research Expedition so as to make an estimation of the large GRV meteorite collection. The chemical-petrographic types of these meteorites are presented below: 1 H3,2 H4, 4 H5, 2 H6, 1 L4, 7 L5, 5 L6, 1 LL4 and 1 LL6. The new data weaken the previous report that unequilibrated ordinary chondrites are unusually abundant in the Grove Mountains region. However, this work confirms significant differences in distribution patterns of chemical-petrographic types between the Grove Mountains and other regions in Antarctica. Many of these meteorites show significant terrestrial weathering, probably due to a high abundance ratio of meteorites found in moraines to those on blue ice. Nine meteorites experienced severe shock metamorphism, as evidenced by undulose extinction and intense fracturing of silicates and presence of shock-induced melt veins and pockets. These heavily shocked meteorites provided us with natural samples for the study of high-pressure polymorphs of minerals.

The Effect of Solar Activity on the Annual Precipitation in the Beijing Area

Using continuous wavelet transform, we examine the relationship between solar activity and the annual precipitation in the Beijing area. The results indicate that the annual precipitation is closely related to the variation of sunspot numbers, and that solar activity probably plays an important role in influencing the precipitation on land.

Reflectance Spectral Characteristics of Lunar Surface Materials

Based on a comprehensive analysis of the mineral composition of major lunarrocks (highland anorthosite, lunar mare basalt and KREEP rock), we investigate the reflectancespectral characteristics of the lunar rock-forming minerals, including feldspar, pyroxene andolivine. The affecting factors, the variation of the intensity of solar radiation with wavelengthand the reflectance spectra of the lunar rocks are studied. We also calculate the reflectivity oflunar mare basalt and highland anorthosite at 300 nm, 415 nm, 750 nm, 900 nm, 950 nm and 1000 nm. Itis considered that the difference in composition between lunar mare basalt and highland anorthositeis so large that separate analyses are needed in the study of the reflectivity of lunar surfacematerials in the two regions covered by mare basalt and highland anorthosite, and especially in theregion with high Th contents, which may be the KREEP-distributed region.

Active Optics in LAMOST

Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is one of the major national projects under construction in China. Active optics is one of the most important technologies for new large telescopes. It is used for correcting telescope errors generated by gravitational and thermal changes. Here, however, we use this technology to realize the configuration of LAMOST,—a task that cannot be done in the traditional way. A comprehensive and intensive research on the active optics used in LAMOST is also reported, including an open-loop control method and an auxiliary closed-loop control method. Another important development is in our pre-calibration method of open-loop control, which is with some new features: simultaneous calculation of the forces and displacements of force actuators and displacement actuators; the profile of mirror can be arbitrary; the mirror surface shape is not expressed by a fitting polynomial, but is derived from the mirror surface shape formula which is highly accurate; a proof is given that the solution of the pre-calibration method is the same as the least squares solution.

Wavelet Analysis of Several Important Periodic Properties in the Relative Sunspot Numbers

We investigate the wavelet transform of yearly mean relative sunspot number series from 1700 to 2002. The curve of the global wavelet power spectrum peaks at 11-yr, 53-yr and 101-yr periods. The evolution of the amplitudes of the three periods is studied. The results show that around 1750 and 1800, the amplitude of the 53-yr period was much higher than that of the the 11-yr period, that the ca. 53-yr period was apparent only for the interval from 1725 to 1850, and was very low after 1850, that around 1750, 1800 and 1900, the amplitude of the 101-yr period was higher than that of the 11-yr period and that, from 1940 to 2000, the 11-yr period greatly dominates over the other two periods.

Corrections to Solar Thermal Structure when a Turbulent Magnetic Field is Included

Correction of non-ideal effect due to a magnetic fluctuating tensor is derived from the ideal MHD equations. The inclusion of a magnetic turbulent field leads to modifications of the hydrostatic equilibrium equation and thermodynamical variables such as the temperature T, the adiabatic exponent γ, the adiabatic temperature gradient ?ad and the temperature gradient ?. In particular, the modifications in the adiabatic and radiative temperature gradients will result in a change in the Schwarzchild criterion, hence in the location of the base of the convective zone. Incorporating the modifications, we construct a modified thermodynamical equilibrium structure of the Sun.

The Importance of Time Synchronization in the Local Networks of the Science and Application Center for Lunar and Deep-space Exploration

The data acquisition stations and the data processing center of the Science and Application Center for Lunar and Deep-space Exploration (SACLuDE) are located at different geographical sites. They respectively have their own local networks and interconnect with each other through access to the core data network. This paper describes the clock drift in the computer and other networked devices building up the infrastructure of the above local networks. The network time variance of the stochastic model is also estimated. The poor precision of network synchronization will bring about potential hazards to the network operation and application running in the networks, which is clarified in the present paper. At the end of the paper, a cost-effective and feasible solution is proposed based on the Global Position System (GPS) and the Network Time Protocol (NTP).

Distribution of Helical Properties of Solar Magnetic Fields

We summarize studies of helical properties of solar magnetic fields such as current helicity and twist of magnetic fields in solar active regions (ARs), that are observational tracers of the alpha-effect in the solar convective zone (SCZ). Information on their spatial distribution is obtained by analysis of systematic magnetographic observations of active regions taken at Huairou Solar Observing Station of National Astronomical Observatories of Chinese Academy of Sciences. The main property is that the tracers of the alpha-effect are antisymmetric about the solar equator. Identifying longitudinal migration of active regions with their individual rotation rates and taking into account the internal differential rotation law within the SCZ known from helioseismology, we deduce the distribution of the effect over depth. We have found evidence that the alpha-effect changes its value and sign near the bottom of the SCZ, and this is in accord with the theoretical studies and numerical simulations. We discuss other regularities which can be revealed by further analysis such as possible dependence on longitude, time, and magnetic field strength, etc.

Verification of a Similar Cycle Prediction for the Ascending and Peak Phases of Solar Cycle 23

Reviews of long-term predictions of solar cycles have shown that a precise prediction with a lead time of 2 years or more of a solar cycle remains an unsolved problem. We used a simple method, the method of similar cycles, to make long-term predictions of not only the maximum amplitude but also the smoothed monthly mean sunspot number for every month of Solar Cycle 23. We verify and compare our prediction with the latest available observational results.

Statistical Properties of the Highest Pulses in Gamma-Ray Bursts

We study the statistical properties of the highest pulses within individual gamma-ray bursts (GRBs). A wavelet package analysis technique and a developed pulse-finding algorithm have been applied to identify the highest pulses from burst profiles observed by BATSE on board CGRO from 1991 April 21 to 1999 January 26. The statistical light curves of the highest pulses in four energy channels have been derived by an aligning method, which illustrate the temporal evolution of the pulse emission. Our result that narrower pulses go with higher energies is consistent with previous findings. By normalizing both the pulse durations and counts to unity, 'characteristic' profiles of the highest pulses in the four channels are also derived. The four characteristic profiles are turned out to be almost the same, thus strongly support the previous conclusion that the temporal profiles in different energy channels are self-similar and the previous conjecture on GRB pulses, implying that the emission process is similar at different energies. The cosmological time dilation effect is examined by investigating the relationship between the pulse flux and pulse duration. An anti-correlation between the two was found, which agrees with the expectation of the cosmological time dilation effect. Also, the evolution of the pulse duration with the observational epoch is studied. The result shows that the pulse duration tends to be shorter in later epochs. This trend cannot be explained by the present theoretical models, and may represent a great challenge to current theories.

Atmospheric Drag Perturbation in an Autonomous Orbit Determination for Satellite

In this paper, an autonomous orbit determination method for satellite using a large field of view star sensor is presented. The simulation of orbit under atmospheric drag perturbation are given with expanded Kalman filtering. The large field of view star sensor has the same precision as star sensor and a sufficient filed of view. Therefore ,the refraction stars can be observed more accurately in real time. The geometric relation between the refracted starlight and the earth can be determined by tangent altitude of the refraction starlight. And then the earth center can be determined in satellite body frame. The simulation shows that the precision of the mean square deviation of satellite’s position and velocity is 5m and 0.01m/s respectively. The calculated decrement of the semi-major axis in one day is close to the theoretical result, and the absolute error is in the range of decimeter when the altitude of orbit is 750 km. The simu- lateion of orbit of different initial semi-major axis shows that the higher the altitude of orbit is, the smaller the dec- rement of the semi-major axis is, and when the altitude of orbit is 1700 km the decimeter of the semi-major axis is 10-7 km.

On the Line Formation in Stellar Magnetized Atmospheres

The line formation process in stellar magnetized atmospheres is studied by observing the wavelength- dependence of Stokes contribution functions. The influence of magnetic field on the escape line photon distribution and line absorption is obtained by comparing with the null magnetic field case. Two models airs adopted. One assumes limited distributions of both the line absorption and magnetic field where a hypothetical magneto-sensitive line is formed. The other is a model atmosphere of sunspot umbra in which MgI 5172.7 forms. It is found that the magnetic field influences the formation region of Stokes I at wavelengths sufficient close to the Zeeman splitting points ±△ H. The formation regions at wavelengths far away from the Zeeman splitting points generally show a non-magnetic behaviour. Further, if the line core is split by the Zeeman effect, the line formation core introduced in the previous paper disappears. On the other hand, Stokes Q, U, V at each wavelength within the line form in the same layers where both the line absorption and magnetic field are present in the models accepted for the lines used. When the line absorption and magnetic field ubiquitously exist, the formation regions of the T peaks or valleys of Stokes Q, U and those of σ of Stokes V generally cover the widest depth range. It is pointed out that such a study is instructive in the explanation of solar polarized filtergrams. It can tell us at each observation point where the received line photons of wavelengths within the bandpass come from and where their polarization states are formed or give us the distributions of these photons as well as their polarization intensities. Thus a three-dimensional image can be constructed for a morphologic study of the observed area from serial filtergrams.

Formation of Solar Delta Active Regions:Twist and Writhe of Magnetic Ropes

We analyze the process of formation of delta configuration in some well-known super active regions based on photospheric vector magnetogram observations. It is found that the magnetic field in the initial developing stage of some delta active regions shows a potential-like configuration in the solar atmosphere, the magnetic shear develops mainly near the magnetic neutral line with magnetic islands of opposite polarities, and the large-scale photospheric twisted field forming gradually later. Some results are obtained: (1) The analysis of magnetic writhe of whole active regions cannot be limited in the strong field of sunspots, because the contribution of the fraction of decayed magnetic field is non-negligible. (2) The magnetic model of kink magnetic ropes, supposed to be generated in the subatmosphere, is not consistent with the evolution of large-scale twisted photospheric transverse magnetic field and not entirely consistent with the relationship with magnetic shear in some delta active regions. (3) The proposition is that the large-scale delta active regions are formed from contribution by small-scale non-potential magnetic flux bundles generated in the subatmosphere.

Calibration of Vector Magnetogram with the Nonlinear Least-squares Fitting Technique

To acquire Stokes profiles from observations of a simple sunspot with the Video Vector Magnetograph at Huairou Solar Observing Station (HSOS), we scanned the FeI λ5324.19 A line over the wavelength interval from 150mA redward of the line center to 150mA blueward, in steps of 10mA. With the technique of analytic inversion of Stokes profiles via nonlinear least-squares, we present the calibration coefficients for the HSOS vector magnetic magnetogram. We obtained the theoretical calibration error with linear expressions derived from the Unno-Becker equation under weak-field approximation.

Wavelet Cleaning of Solar Dynamic Radio Spectrograms

By applying the state-of-the-art mathematical apparatus, the wavelet transformation, we explore the possibility of a dynamic cleaning of raw data ob- tained with the Chinese solar radio spectrographs over a wide wavelength range (from 0.7 to 7.6 GHz). We consider the problem of eliminating the interference caused by combination rates of data sampling (10-20 ins), and the low-frequency interference (4-30 s) caused by the receiving equipment changing its characteristics with time. It is shown that the best choice to reconstruct a signal suffering from amplitude, frequency and phase instabilities, is by means of wavelet transformation at both high and low frequencies. We analysed observational data which contained interferences of nonsolar origin such as instrumental effects and other man-made signals. A subsequent comparison of the reference data obtained with the acousto- optical receiver of the Siberian Solar Radio Telescope (SSRT) with the 'cleaned' spectra confirms the correctness of this approach.

LUNARINFO: A Data Archiving and Retrieving System for the Circumlunar Explorer Based on XML/Web Services

It is essential to build a modern information management system to store and manage data of our circumlunar explorer in order to realize the scientific objectives. It is difficult for an information system based on traditional distributed technology to communicate information and work together among heterogeneous systems in order to meet the new requirement of Internet development. XML and Web Services, because of their open standards and self-containing properties, have changed the mode of information organization and data management. Now they can provide a good solution for building an open, extendable, and compatible information management system, and facilitate interchanging and transferring of data among heterogeneous systems. On the basis of the three-tiered browse/server architectures and the Oracle 9i Database as an information storage platform, we have designed and implemented a data archiving and retrieval system for the circumlunar explorer-LUNARINFO. We have also successfully realized the integration between LUNARINFO and the cosmic dust database system. LUNARINFO consists of five function modules for data management, information publishing, system management, data retrieval, and interface integration. Based on XML and Web Services, it not only is an information database system for archiving, long-term storing, retrieving and publication of lunar reference data related to the circumlunar explorer, but also provides data web Services which can be easily developed by various expert groups and connected to the common information system to realize data resource integration.

Chandra Observations of the Flat Spectrum Seyfert-2 Galaxies NGC 2110 and NGC 7582

Chandra observations of the Seyfert-2 galaxies NGC 2110 and NGC 7582 arepresented. With the superb spatial resolution of Chandra we found that in NGC 7582 the soft (≤2keV) and hard (2-10 keV) X-rays are emitted in different regions, consistent with the report by Xueet al. By comparing the present X-ray data with the previous infrared data, we determined that thesoft X-ray region is the site of starburst activities. We found no significant temporal variationsduring our observations. We confirm the previous finding that NGC 2110 and NGC 7582 areflat-spectrum sources. We argue that the flat spectra may result from a cold absorbing material suchas envisaged in the 'dual absorbed' model. Strong FeK_α emission feature is detected in 6～7keV.Its equivalent width is so large that it cannot be reproduced by using the Galactic column densityof ～ 10^(22) cm^(-2).

The Correlation between Gamma-ray and Radio Emissions in γ-ray Loud Blazars

We collect 119 γ-ray-loud blazars (97 flat spectrum radio quasars (FSRQs) and 22 BL Lacertae objects (BL Lacs)), and investigate possible correlations between their γ-ray emission (maximum, minimum and average values) at 1 GeV and the radio emission at 8.4 GHz. Our main results are as follows. For the lower state γ-ray data, there is no correlation between the γ-ray and radio flux density; For the high state γ-ray data, there are good correlations for the whole 119 blazars and 97 FSRQs, and a weak correlation for the 22 BL Lac objects; For the average γ-ray data, there are good correlations. According to our analysis, we propose that the γ-rays are associated with the radio emission from the jet, and that the γ-ray emission is likely from the SSC process in this case.

Radioactive Ages of Metal-Poor Halo Stars

The abundances of long-lived radioactive elements Th and U observed in metal-poor halo stars can be used as chronometers to determine the age of individual stars, and hence set a lower limit on the age of the Galaxy and hence of the universe. This radioactive dating requires the zero-decay productions of Th and U, which involves complicated r-process nucleosynthesis calculations. Several parametric r-process models have been used to calculate the initial abundance ratios of Th/Eu and U/Th, but, due to the sharp sensitivity of these models to nuclear physics inputs, the calculations have relatively large uncertainties which lead to large uncertainties in the age determinations. In order to reduce these uncertainties, we present a simple method to estimate the initial productions of Th and U, which only depends on the solar system abundances and the stellar abundances of stable r-process elements. From our calculations of the initial abundance ratios of Th/Eu and U/Th, we re-estimate the ages of those very metal-poor halo stars with published abundances of Th and U. Our age estimates are consistent, within the errors, with the other age determinations derived from r-process models, and offer useful constrains for r-process theoretical calculations. The advantages and limitations of our simple method of radioactive dating are discussed.