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核心期刊

Research in Astronomy and Astrophysics [RAA]

基本信息

出版信息

  • 出版时间:1981年-
  • 出版者:中国科学院国家天文台
  • 出版格式:
  • 总访问量:6947次

期刊简介

    《天文和天体物理学研究》(英)是中国科学院国家天文台和中国天文学会主办的学术期刊,发表天文学和天体物理学领域高水平原创性的研究成果,旨在反映我国及整个亚洲和太平洋地区的天文学的进展

  • 2.5 m Space Station Co-orbiting Coaxial Telescope

    DOI:https://doi.org/10.1088/1674-4527/adc4b1

    提交时间: 2025-06-13

    摘要:The China Space Station Telescope (CSST) is primarily designed for large-scale multi-color imaging and seamless spectroscopic survey, while also accommodating observations with an integral field spectrograph (IFS), multi-channel imaging, direct imaging of exoplanets, and terahertz-band observations. It is scheduled to be launched in about 2 yr. The telescope is equipped with a variety of terminal instruments. It has important scientific missions but limited observation time, so it is suggested to develop a 2.5 m coaxial telescope that will be co-orbiting with the space station. This additional telescope will mainly focus on time-domain surveys and IFS surveys. Its development budget is lower than the current 2 m off-axis telescope, CSST, but it offers superior system performance. Within the limited operational lifespan of the space station, it can significantly enhance the existing survey efficiency. Like the CSST, this telescope will be able to do multi-color imaging survey, and time-domain surveys are also under consideration.

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  • MHD Simulations of the Slow-rise Phase of Solar Eruptions Initiated from a Sheared Magnetic Arcade

    DOI:https://doi.org/10.1088/1674-4527/adcb8e

    提交时间: 2025-06-13

    摘要:Before solar eruptions, a short-term slow-rise phase is often observed, during which the pre-eruption structure ascends at speeds much greater than the photospheric motions but much less than those of the eruption phase. Numerical magnetohydrodynamic (MHD) simulations of the coronal evolution driven by photospheric motions up to eruptions have been used to explain the slow-rise phase, but their bottom driving speeds are much larger than realistic photospheric values. Therefore, it remains an open question how the excessively fast bottom driving impacts the slow-rise phase. Here we modeled the slow-rise phase before eruption initiated from a continuously sheared magnetic arcade. In particular, we performed a series of experiments with the bottom driving speed unprecedentedly approaching the photospheric value of around 1 km s−1. The simulations confirmed that the slow-rise phase is an ideal MHD process, i.e., a manifestation of the growing expansion of the sheared arcade in the process of approaching a fully open field state. The overlying field line above the core flux has a slow-rise speed modulated by the driving speed's magnitude but is always over an order of magnitude larger than the driving speed. The core field also expands with speed much higher than the driving speed but much lower than that of the overlying field. By incrementally reducing the bottom-driving speed to realistic photospheric values, we anticipate better matches between the simulated slow-rise speeds and some observed ones.

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  • Stellar Parameters, Extinction, and Distances for Stars in SMSS DR2 by the SPar Method

    DOI:https://doi.org/10.1088/1674-4527/adc5e1

    提交时间: 2025-06-13

    摘要:The availability of large data sets containing stellar parameters, distances, and extinctions for stars in the Milky Way, particularly within the Galactic disk, is essential for advancing our understanding of the Galaxy's stellar populations, structure, kinematics, and chemical evolution. In this study, we present a catalog of stellar parameters, including effective temperature (Teff), metallicity ([Fe/H]), absolute magnitudes (MG), distances (d), and reddening values (E(GBP − GRP)), for a sample of 141 million stars from the SkyMapper Southern Survey. These parameters are derived using the SPar algorithm, which employs a fitting procedure to match multi-band photometric observations and estimate the stellar properties (Teff, [Fe/H], MG, d, and E(GBP − GRP)) on an individual star basis, following the methodology outlined in our previous work. This study successfully determines stellar parameters and extinction values simultaneously for stars located in high and low Galactic latitudes. The resulting stellar parameters and extinction values are in good agreement with results from other studies, demonstrating the robustness of our method. We derive a temperature dispersion of 195 K and a metallicity dispersion of 0.31 dex when comparing our results with spectroscopic data. The catalog produced in this work provides a valuable resource for future research on the Galactic metallicity distribution function,the structure of the Galaxy,three-dimensional extinction mapping,and other related astrophysical topics.

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  • LAMOST Spectral Data Processing: Classification, Redshift Measurement, and Data Product Creation

    DOI:https://doi.org/10.1088/1674-4527/adcb8b

    提交时间: 2025-06-13

    摘要:The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) has become a crucial resource in astronomical research, offering a vast amount of spectral data for stars, galaxies, and quasars. This paper presents the data processing methods used by LAMOST, focusing on the classification and redshift measurement of large spectral data sets through template matching, as well as the creation of data products. Additionally, this paper details the construction of the Multiple Epoch Catalogs by integrating LAMOST spectral data with photometric data from Gaia and Pan-STARRS, and explains the creation of both low- and medium-resolution data products.

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  • Development of 6 inch 80–170 GHz Broadband Silicon Plated Horn Antenna Arrays for Primordial Gravitational Wave Search

    DOI:https://doi.org/10.1088/1674-4527/adc187

    提交时间: 2025-06-13

    摘要:Searching for primordial gravitational waves in the cosmic microwave background (CMB) polarization signal is one of the key topics in modern cosmology. Cutting-edge CMB telescopes require thousands of pixels to maximize mapping speed. Using a modular design, the telescope focal plane is simplified to several detector modules. Each module has hundreds of pixels including antenna arrays, detector arrays, and readout arrays. The antenna arrays, as the beam defining component, determine the overall optical response of the detector module. In this article,we present the developments of 6 inch broadband antenna arrays from 80 to 170 GHz for the future IHEP focal plane module. The arrays are fabricated from 42 6 inch silicon wafers including 456 antennas,7% more pixels than the usual design. The overall in-band cross polarization is smaller than −20 dB and the in-band beam asymmetry is smaller than 10%,fulfilling the requirements for primordial gravitational wave search.

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  • Timing and Spectral Analysis of 4U 1626-67 Using AstroSat/LAXPC

    DOI:https://doi.org/10.1088/1674-4527/adc789

    提交时间: 2025-06-13

    摘要:We present a comprehensive analysis of AstroSat/LAXPC data of the second spin-up and second spin-down phases of the persistent X-ray pulsar 4U 1626-67. Flares followed by a broad dip are detected in the spin-up observations. The pulse profiles changed from a shoulder-like structure to a broad sinusoidal shape as the source underwent a torque reversal from spin-up to spin-down. Energy-resolved pulse profiles in lower energies showed a double-horned profile in the spin-up state and a flat top with multiple peaks in the spin-down state. Regardless of the torque state, the pulse profiles exhibit a broad single-peaked shape at higher energies. The observation in the spin-down era is characterized by the presence of a prominent QPO at 46.5 ± 1.0 mHz frequency. The QPO rms and center frequency show a correlation with energy. Spin-up and spin-down states show a difference in the shape of the power density spectrum. After the torque reversal, a gradual flux drop and the hardening of the spectra were observed. The difference in the shape of the pulse profiles and the presence and absence of QPOs can be explained by the change in accretion flow geometry of the pulsar, from pencil-beam to fan-beam,between spin-down and spin-up states.

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  • The Fall and Origins of the Meteoroid Tanxi

    DOI:https://doi.org/10.1088/1674-4527/adc85d

    提交时间: 2025-06-13

    摘要:Integrating available instrumental records with meteorite analysis could build a link between meteorite chemical groups and their original parent bodies. However,such comprehensive source region-tracing studies have not been conducted for any meteorite fall events in China. On 2022 December 15 at 09:48 UT,meteoroid Tanxi was recorded by numerous cameras in populous northern Zhejiang. This event offers an opportunity to conduct the first systematic origin-tracing study for a meteorite fall event in China. The Tanxi meteorite was classified as an H6 chondrite. This meteoroid entered the atmosphere with a velocity of 13.49 km s−1 and a slope of 69.52°. It most likely underwent a two-stage fragmentation process, with early fragmentation under a dynamic pressure of 0.08 MPa, and main fragmentation under a dynamic pressure of 7.83 MPa. Before colliding with the Earth, the meteoroid's heliocentric orbit had a semimajor axis of 2.363 ± 0.107 au, an eccentricity of 0.584 ± 0.019 and an inclination of 2.078 ± 0.074°. A backward Dsh evolution result of 5000 yr shows Tanxi's orbit is most similar to a small near-Earth asteroid 2016 WV2. The source region analysis of the Tanxi fall indicates that the H chondrites could originate from two distinct reservoirs: the 3:1J mean motion resonance complex (51.2 ± 3.7%) and the v6 secular resonance region (41.6 ± 2.9%).

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  • A New Method to Predict Particle Sizes of Lunar or S-type Asteroid Surfaces Based on The Laboratory Thermal-infrared Data

    DOI:https://doi.org/10.1088/1674-4527/adc6d9

    提交时间: 2025-06-13

    摘要:The surface particle size and distribution characteristics of celestial bodies (e.g., the Moon, asteroids, etc.) will affect the interpretation of hyperspectral remote sensing data and the implementation of sampling missions. Currently, the estimation of the surface particle sizes is mainly focusing on interpreting the thermal inertia with the infrared spectral data from ground-based or space telescopes, but this method show distinct errors compared with the imaging results of the orbiter. By analyzing some thermal infrared spectral data, a relationship between the particle sizes of the main rock-forming minerals (e.g. pyroxene, feldspar, olivine) and the slopes of their thermal infrared spectrum was found. Based on this relationship, a preliminary model for estimating the grain sizes (∼30–300 μm) of lunar or S-type asteroids' surfaces which are silicate minerals dominated was established, and the correlation coefficients (R2) for most of the rock-forming minerals were better than 90%. Six observational datasets of natural lunar and terrestrial samples are used to validate the model, and the results show a systematical overestimation of the ground-truth particle sizes, the potential causes are analyzed and an additional correction is used to eliminate the overestimation of the particle size prediction. These results are expected to provide guidance for interpretation of lunar and S-type asteroid surface sampling and spectral data.

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  • Optimizing the Input of Liouville Convolution Improves the 10 Day Predictions of Polar Motion

    DOI:https://doi.org/10.1088/1674-4527/adc794

    提交时间: 2025-06-13

    摘要:This study addresses the critical technical need to enhance the 1–10 day prediction accuracy of polar motion (PM) in satellite autonomous navigation and deep space exploration, with a focus on optimizing the convolution input accuracy within the least squares and autoregression with effective angular momentum (LS+AR+EAM) method. Through theoretical derivation and numerical experiments, we identify the significant impact of the iterative mechanism of the convolution input in the Liouville equation on PM prediction accuracy. On one hand, it clearly states that the initial step of convolution iteration should begin today using today's daily data, rather than relying on the iterative convolution result from the previous step. On the other hand, due to the requirement for the previous PM, previous geodetic angular momentum (GAM), and current GAM in convolution input, several GAM predictions are constructed using IGS ultra-rapid 6 hr resolution data. Additionally, a hybrid method is used to obtain multiple EAM predictions. By integrating these predictions, the range of prediction errors is effectively constrained. The hindcast results, submitted before 20:00 UTC every Wednesday during the official interval of the second Earth Orientation Parameters Prediction Comparison Campaign (2nd EOP PCC), show that the proposed method improved the mean absolute error (MAE) over the first seven days compared to the first-place method (ID136), with improvements of 51.9%, 32.0%, 28.5%, 20.9%, 19.2%, 17.2%, and 17.0% in the X direction, and 20.6%, 16.2%, 14.4%, 12.8%, 8.7%, 3.1%, and 3.0% in the Y direction. Furthermore, extending the statistical range from 2016/1/6 to 2022/12/28, the proposed method yields MAE values of (0.165, 0.137), (0.735, 0.505), and (1.874, 1.238) mas for days 1, 5, and 10, respectively, outperforming the official predictions by IERS or USNO, which are (0.255, 0.194), (1.534, 1.110), and (2.875, 1.877) mas. This not only validates the stability of the proposed method but also demonstrates its direct applicability in real-world engineering applications.

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  • The Photometric Investigation of Totally Eclipsing Contact Binaries NSVS 9023048 and NSVS 2461789

    DOI:https://doi.org/10.1088/1674-4527/adca8f

    提交时间: 2025-06-13

    摘要:In this paper, new light curve fitting and orbital period change analysis of two contact binaries NSVS 9023048 and NSVS 2461789 are presented. We found that both of them are totally eclipsing contact binaries. Our photometric solutions suggest that NSVS 9023048 is a deep contact binary (q  =  10.14, f = 69.2%), however, NSVS 2461789 is a shallow one (f = 24.4%, q = 3.08). The asymmetric light curves of NSVS 2461789 and NSVS 9023048 can be explained by the star-spot activity. At the same time, using the available eclipse times, we first studied the orbital period changes of these two targets. It is discovered that the period of NSVS 9023048 is decreasing at a rate of dP / dt =  −1.17 × 10−6 day yr−1, which can be explained by mass transfer from the more massive star to the less massive one or angular momentum loss. In addition, the O − C diagrams of NSVS 9023048 and NSVS 2461789 show possible cyclic oscillations with a period of 7.29 yr and 9.91 yr, respectively. The cyclic oscillations may be caused by the light-travel time effect due to the presence of a third component. The mass of the tertiary companion is determined to be M3sin(i3) = 9.05 M⊙ for NSVS 9023048 and M3sin(i3) = 0.11 M⊙ for NSVS 2461789. Based on our calculations, the third body of NSVS 9023048 may be a black hole candidate. Our study also reveals that NSVS 9023048 is stable now.

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