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  • Characteristics and close-range exploration methods of near- Earth asteroid 2016HO3

    分类: 天文学 >> 天文仪器与技术 提交时间: 2024-02-07 合作期刊: 《天文技术与仪器(英文)》

    摘要:The characteristics of asteroids are vital parameters for planning asteroid exploration missions. These characteristics have been explored in close range for some typical asteroids, and are summarized in the article. This allows estimates of the characteristics of asteroid 2016HO3, the target of the first Chinese asteroid exploration mission, Tianwen 2. We obtain 80 characteristic parameters in 9 categories and analyze their impacts on the mission. By comparing three close-range exploration modes, we provide advantages and disadvantages of each, and propose suitable methods for the exploration of 2016HO3. Owing to the weak gravity and small size of 2016HO3, a combination of multiple hovering positions and active orbiting is recommended for scientific exploration.

  • Development and application of high-precision multifunction astronomical plate digitizers in China

    分类: 天文学 >> 天文仪器与技术 提交时间: 2024-02-07 合作期刊: 《天文技术与仪器(英文)》

    摘要:Before charge-coupled device detectors became widely employed in observational astronomy, for more than a hundred years, the main detection method was photography on astronomical glass plates. Recently, in order to preserve these historical data and maintain their usability, the International Astronomical Union has appealed to all countries for global digitization of astronomical plates by developing or adopting advanced digitization technology. Specialized digitizers with high precision and high measuring speed represent key equipment for this task. The Shanghai Astronomical Observatory and the Nishimura Co., Ltd in Japan cooperated between 2013 and 2016 to develop the first Chinese high-precision astronomical plate digitizer, which was then used for complete digitization of all nighttime-observation astronomical plates in China. Then, in 2019–2021, the Shanghai Astronomical Observatory independently developed new models of plate digitizers that enabled countries such as Uzbekistan and Italy to digitize their astronomical plates. Additionally, a new high-precision and multifunction digitizer was also used to digitize valuable microscope slides from the Shanghai Natural History Museum, providing a successful example of crossdomain application of high-precision digitization technology.

  • Application and prospect of the fluid cooling system of solar arrays for probing the Sun

    分类: 天文学 >> 天文仪器与技术 提交时间: 2024-02-07 合作期刊: 《天文技术与仪器(英文)》

    摘要:The Solar Close Observations and Proximity Experiments (SCOPE) mission, which has been proposed by the Yunnan Observatories, Chinese Academy of Sciences, aiming to operate at a distance of 5 to 10 solar radii from the Sun, plans to complete the in situ detection of the solar eruption process and observation of the magnetic field structure response. The solar flux received by the satellite ranges from 103 to 106 Wm−2, which poses challenges for thermal management of the solar arrays. In this work, the solar array cooling system of the Parker Solar Probe is discussed, the developments of the fluid loop technique are reviewed, and a research plan for a next-generation solar array cooling system is proposed. This paper provides a valuable reference for novel thermal control systems in spacecraft for solar observation.

  • Design and analysis of an advanced thermal management system for the solar close observations and proximity experiments spacecraft

    分类: 天文学 >> 天文仪器与技术 提交时间: 2024-02-07 合作期刊: 《天文技术与仪器(英文)》

    摘要:In this paper, the mission and the thermal environment of the Solar Close Observations and Proximity Experiments (SCOPE) spacecraft are analyzed, and an advanced thermal management system (ATMS) is designed for it. The relationship and functions of the integrated database, the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon. For the complex thermal field regulation system and extreme space thermal environment, a modular simulation and thermal field planning method are proposed, and the feasibility of the planning algorithm is verified by numerical simulation. A solar array liquid cooling system is developed, and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion. The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.

  • The Jiao Tong University Spectroscopic Telescope Project

    分类: 天文学 >> 天文仪器与技术 提交时间: 2024-02-07 合作期刊: 《天文技术与仪器(英文)》

    摘要:The Jiao Tong University Spectroscopic Telescope (JUST) is a 4.4-meter f/6.0 segmented-mirror telescope dedicated to spectroscopic observations. The JUST primary mirror is composed of 18 hexagonal segments, each with a diameter of 1.1 m. JUST provides two Nasmyth platforms for placing science instruments. One Nasmyth focus fits a field of view of 10 ′ and the other has an extended field of view of 1.2° with correction optics. A tertiary mirror is used to switch between the two Nasmyth foci. JUST will be installed at a site at Lenghu in Qinghai Province, China, and will conduct spectroscopic observations with three types of instruments to explore the dark universe, trace the dynamic universe, and search for exoplanets: (1) a multi-fiber (2000 fibers) medium-resolution spectrometer (R=4 000−5 000) to spectroscopically map galaxies and large-scale structure; (2) an integral field unit (IFU) array of 500 optical fibers and/or a long-slit spectrograph dedicated to fast follow-ups of transient sources for multi-messenger astronomy; (3) a high-resolution spectrometer (R~100 000) designed to identify Jupiter analogs and Earth-like planets, with the capability to characterize the atmospheres of hot exoplanets.

  • Review of artificial intelligence applications in astronomical data processing

    分类: 天文学 >> 天文仪器与技术 提交时间: 2024-02-07 合作期刊: 《天文技术与仪器(英文)》

    摘要:Artificial Intelligence (AI) is an interdisciplinary research field with widespread applications. It aims at developing theoretical, methodological, technological, and applied systems that simulate, enhance, and assist human intelligence. Recently, notable accomplishments of artificial intelligence technology have been achieved in astronomical data processing, establishing this technology as central to numerous astronomical research areas such as radio astronomy, stellar and galactic (Milky Way) studies, exoplanets surveys, cosmology, and solar physics. This article systematically reviews representative applications of artificial intelligence technology to astronomical data processing, with comprehensive description of specific cases: pulsar candidate identification, fast radio burst detection, gravitational wave detection, spectral classification, and radio frequency interference mitigation. Furthermore, it discusses possible future applications to provide perspectives for astronomical research in the artificial intelligence era.

  • Review of artificial intelligence applications in astronomical data processing

    分类: 天文学 >> 天文仪器与技术 提交时间: 2024-02-07 合作期刊: 《天文技术与仪器(英文)》

    摘要:Artificial Intelligence (AI) is an interdisciplinary research field with widespread applications. It aims at developing theoretical, methodological, technological, and applied systems that simulate, enhance, and assist human intelligence. Recently, notable accomplishments of artificial intelligence technology have been achieved in astronomical data processing, establishing this technology as central to numerous astronomical research areas such as radio astronomy, stellar and galactic (Milky Way) studies, exoplanets surveys, cosmology, and solar physics. This article systematically reviews representative applications of artificial intelligence technology to astronomical data processing, with comprehensive description of specific cases: pulsar candidate identification, fast radio burst detection, gravitational wave detection, spectral classification, and radio frequency interference mitigation. Furthermore, it discusses possible future applications to provide perspectives for astronomical research in the artificial intelligence era.

  • 基于无量纲的轨道参数开展卫星性质统计研究

    分类: 提交时间: 2024-01-31 合作期刊: 《天文学报》

    摘要: 目前已发现了285颗围绕太阳系八大行星公转的卫星, 它们的轨道和物理性质呈现了丰富多样性. 目前为止, 几乎所有的卫星研究工作都基于单个卫星系统或者卫星群, 似乎缺少统一的研究. 提出了一个新的与行星性质无关、只与恒星半径有关的轨道参数$n$, 定义为以太阳半径为单位的轨道半长轴的自然对数. 不同行星的卫星的$n$值都存在双极分布, 绝大部分卫星在$n\gtrsim2$区间, 其次在$n\lesssim-1$区间, 位于中间区域的行星则很少. 从卫星物理参数和轨道参数与$n$的关系中发现, 分属六大行星的卫星有明显的共同特征. 首先, 轨道偏心率和轨道倾角偏大的卫星的$n$值都在3.5左右, 它们都是巨行星的不规则卫星. 其次, $n$值在$-$1和1之间的卫星绝大部分体积大、质量大、反照率高、自转速度慢. 从文献中找到11颗系外卫星候选体, 获得了它们轨道$n$值和卫星质量, 发现后者也是在$-1展开 -->

  • 一种新的守时型原子钟综合时间尺度方法研究

    分类: 提交时间: 2024-01-31 合作期刊: 《天文学报》

    摘要: 在这篇文章中, 提出了一种基于改进的指数平滑和Vondrak\_Cepek联合平滑的氢铯综合时间尺度产生方法. 以最小误差方法为理论基础, 动态估计氢原子钟频率漂移参数, 提升氢原子钟钟差预测准确度; 基于改进的二次指数平滑产生氢原子钟组时间尺度、加权平均方法产生铯原子钟时间尺度, 同时设计Vondrak\_Cepek滤波器以结合两类时间尺度长短期稳定度优势, 提升综合时间尺度性能. 实验结果表明, 所提方法产生的氢铯综合时间尺度时稳可达$1.60 \times 10^{-15}$, 天稳可达$3 \times 10^{-15}$, 优于ALGOS、AT1和Kalman滤波3种经典方法产生的时间尺度性能.

  • 高层大气密度的午夜极大值特征分析与建模

    分类: 提交时间: 2024-01-31 合作期刊: 《天文学报》

    摘要: 利用CHAMP (CHAllenging Minisatellite Payload)、GRACE-A (Gravity Recovery and Climate Experiment-A)、SWARM-C (The Earth's Magnetic Field and Environment Explorers-C)等3颗极轨卫星的资料, 研究360--480\;km高层大气密度在低纬度区域的午夜极大值(Midnight Density Maximum, MDM)现象. MDM一般出现在23:00---02:00\;LT (Local Time)之间, 峰值位置在低纬度${15}^\circ$以内, 谷值位置在中纬度${35}^\circ$--${45}^\circ$附近, 整体略偏向南半球, 振幅约为平均密度的26\%. 随着高度增大以及太阳辐射水平的增强, MDM振幅呈减小趋势; 冬至和夏至日附近的季节效应会减弱MDM振幅, 在春秋分日的振幅最大. 用3个主流大气模型\lk DTM2000 (Drag Temperature Model 2000), NRLMSISE00 (US Naval Research Laboratory, Mass Spectrometer and Incoherent Scatter radar)和JB2008 (Jacchia-Bowman 2008 model)对MDM进行模拟, JB2008没有刻画出MDM现象; 另两个模型低估了MDM效应, 在360\;km和480\;km两个高度DTM2000模型的振幅仅为观测的46\%和53\%, NRLMSISE00模型仅为观测的33\%和26\%; 模型没有准确刻画出MDM与高度、辐射水平和季节的关系. 联合3颗卫星的资料, 研究了一种基于地理纬度的6阶勒让德多项式, 同时融合地方时和高度因素的经验函数, 在振幅和相位上可以较好地刻画MDM特征, 相关系数达到0.923, 可为大气密度模型的修正提供借鉴, 服务于低轨道航天器高精度轨道预报.

  • 太阳黑子本影振荡的多波段观测

    分类: 提交时间: 2024-01-31 合作期刊: 《天文学报》

    摘要: 基于多波段的观测数据, 研究了黑子本影振荡在太阳大气不同高度或温度的振荡特征. 目标黑子发生在2017年9月15日, 位于活动区12680. 多波段的观测数据包括AIA (Atmospheric Imaging Assembly)的极紫外成像及IRIS (Interface Region Imaging Spectrograph)的紫外光谱和成像. 在太阳黑子的本影位置, AIA 1700\;{\AA}\lk光变曲线的振荡周期约为(4.2$\pm$0.8)\;min, 而AIA 1600\;{\AA}、171\;{\AA}和193\;{\AA}光变曲线的振荡周期约为(2.8$\pm$0.3)\;\lk min. IRIS 的Mg II h和k谱线及远紫外成像(2796\;{\AA})都表现为(3.1$\pm$0.5)\;min的准周期振荡, 而谱线Si IV 1393.76\;\lk{\AA}的振荡周期约为(2.9$\pm$0.4)\;min. 观测结果说明黑子本影的振荡周期随着太阳大气高度的升高而逐渐减小. \lk较短的周期可认为是3\;min振荡, 很可能与黑子本影上方的慢磁声波有关, 它起源于温度极小区并向上传播到日冕. 较长的周期可解释为光球的5\;min振荡, 与太阳的P模振荡有关.

  • 基于CEI测量的GEO目标快速轨道恢复

    分类: 提交时间: 2024-01-31 合作期刊: 《天文学报》

    摘要: 连线干涉测量(Connected Element Interferometry, CEI)是一种全天时全天候的被动测角技术, 已用于空间目标的跟踪监视. 地球静止轨道(Geostationary Earth Orbit, GEO)卫星需要频繁机动以保持轨位或完成其他任务, 其机动后的快速轨道恢复能力对于监视预警极为重要. 针对基于CEI的GEO短弧定轨和预报, 分析了定轨算法的形亏和数亏, 在附加先验轨道约束的短弧定轨基础上, 提出了轨道半长轴初值的自适应优化方法. 利用亚太七号卫星的CEI仿真和实测数据进行了短弧定轨和预报, 实验结果表明, 采用优化后的半长轴初值, 30\;min短弧定轨和10\;min预报的卫星位置分量精度均优于4\;km, 能够满足非合作GEO目标机动后快速轨道恢复的需求.

  • 基于嵌入式人工智能设备的流星光学监测系统

    分类: 提交时间: 2024-01-31 合作期刊: 《天文学报》

    摘要: 流星光学监测网是定位陨石和观测火流星的基础科研设施. 流星光学监测系统利用光学相机高速采集天空图像, 使用嵌入式系统实时处理数据, 能够快速识别流星并获取流星位置和陨石落点信息, 是构成流星监测网的关键仪器. 为提高流星光学监测系统获取信息的实时性及准确性, 提出了一种基于嵌入式人工智能设备的流星光学监测系统. 该系统由软件及硬件部分组成: 硬件部分包括观测设备(商用高空抛物摄像头)以及数据处理设备(嵌入式人工智能设备); 软件部分运行于数据处理设备内, 主要包括控制界面模块、流星监测模块、数据管理模块. 实际工作时, 摄像头采集天空视频信息, 流星监测模块从视频流中实时监测流星并存储包含流星视频的数据, 数据管理模块将流星位置信息实时传回数据中心用于预警. 观测结束后, 将原始观测数据同步至数据中心用于后续科学研究. 在整个系统中, 流星监测模块决定了整个监测系统的实时性及准确性. 该系统采用嵌入式人工智能设备与人工智能算法结合的方法构建流星监测模块. 通过使用实测数据对搭载监测模块性能进行测试, 结果表明: 流星监测模块能够达到0.28\%的低误检率以及100\%的召回率, 且数据处理速度达到了Mobilenetv2的8倍. 进一步将包含监测模块的整个流星光学监测系统部署于太原理工大学-张壁古堡远程天文台, 通过实测表明流星光学监测系统实用中能达到100\%的召回率和较低的误检率.

  • NWA 13943(CK5型)碳质球粒陨石的矿物岩石学和稳定同位素组成研究

    分类: 提交时间: 2024-01-31 合作期刊: 《天文学报》

    摘要: CK型陨石是一类高度氧化的碳质球粒陨石, 金属/磁铁矿的比值接近零. 与其它类型的碳质球粒陨石(岩石类型: 1--3)不同, 大多数CK型陨石在母体上经历了强烈的热变质过程(550--1270\;K), 以4--6型为主. 多项证据表明, CK和CV3型陨石具有成因联系. 但是, 两者在岩相结构和化学组成方面仍存在微小差异. 因此, 精细地区分和比较两者的地球化学特征对于验证CK-CV单一母体假说非常重要. Northwest Africa (NWA) 13943是一块新发现的陨石, 经历过较强烈的热变质作用. 利用扫描电子显微镜和电子探针, 确定了NWA 13943的岩石类型. 并运用质谱分析技术, 重点测定了NWA 13943陨石的全岩氧同位素和铬同位素组成. 综合岩石结构、矿物化学成分、氧同位素异常($\Delta^{17}$O, $\Delta$代表同位素分馏值)和铬同位素异常($\varepsilon^{54}$Cr, $\varepsilon$表示样品中的同位素比值与标样中的同位素比值的相对偏差的10$^{4}$倍), CK和CV型陨石的母体可能形成于原行星盘中两个相似但不同的化学源区.

  • BDS-3新频点信号双频精密单点定位精度分析

    分类: 提交时间: 2024-01-31 合作期刊: 《天文学报》

    摘要: 北斗卫星导航系统(BeiDou navigation satellite System, BDS)已于2020年7月正式建成并开通, 北斗三号(BDS-3)在旧信号B1I和B3I的基础上, 增加了B1C、B2a新信号. 为了全面评估BDS-3的新信号B1C、B2a的定位性能, 试验了GPS (Global Positioning System)、BDS-3、BDS-2/BDS-3新旧信号的定位性能和BDS系统不同频点与GPS组合定位性能, 对BDS (B1I+B3I、B1C/B2a)+GPS (L1+L2)组合静态PPP (Precise Point Positioning)定位性能进行分析, 并与单卫星系统对比分析. 试验结果表明: BDS-3 (B1C/B2a)在East (E)、\lk North (N)、Up (U)方向的定位精度优于1.25\;cm、0.89\;cm、1.67\;cm, BDS-3新旧频点在E、N方向上定位精度与GPS L1/L2 在同一水平上, U方向上新频点定位精度高于GPS L1/L2和BDS-3旧频点, 较旧频点定位精度提升了34.2\%, 新频点收敛时间25.9\;min比旧频点提升了12.7\%; 相较于BDS、GPS单系统, 组合系统BDS/GPS定位精度和收敛时间有了明显的提高, BDS-3 (B1C/B2a)+GPS在E、N方向上与BDS-3 (B1I/B3I)+GPS定位精度相当, 在U方向上定位精度前者较后者有了明显的提升, 提升了17.2\%, 组合系统新频点收敛时间20.1\;min比旧频点提升了17.6\%.

  • 球状星团成员星的空间相关性分析

    分类: 提交时间: 2024-01-31 合作期刊: 《天文学报》

    摘要: 以球状星团NGC (New General Catalogue) 104、NGC 5139、NGC 6121为实验样区, 选取了视差等10个恒星参数, 通过引入地学中的空间分析理论和相应的分析框架为定量描述球状星团成员星的空间分布特征提出了一种基于地学的研究范式. 通过计算全局和局部莫兰(Moran)指数得到球状星团成员星各恒星参数的空间分布特征. 研究结果表明: 球状星团NGC 104、NGC 5139、NGC 6121成员星的各恒星参数在总体上呈现出空间正相关特性, 表现出空间集聚特征, 但不同恒星参数之间存在差异; 局部空间分布也呈现聚集特征, 而不同的成员星呈现出不同的空间分布特性和趋势. 总体而言, 用地学空间相关分析系统地定量化描述球状星团成员星空间分布特征, 能够为球状星团的研究提供新的思路.

  • 面向新疆奇台110 m射电望远镜宽带双极化Vivaldi馈源设计

    分类: 提交时间: 2024-01-31 合作期刊: 《天文学报》

    摘要: 射电望远镜一般要在宽频段内进行连续观测, 但传统相控阵天线设计方法难以兼顾宽频带和大角度扫描特性. 紧耦合天线的设计方法为宽带大角度扫描天线提供了新的设计思路, 基于此设计了一款宽带双极化\lk Vivaldi相控阵馈源. 首先结合Wheeler提出的连续电流片概念及等效电路对紧耦合原理进行理论分析, 然后针对Vivaldi天线分析了阵元间的强耦合能够有效拓展天线的工作带宽. 在此基础上设计了一款宽带Vivaldi相控阵馈源. 馈源阵列由8$\times$9 Vivaldi天线阵元组成, 该阵列的工作带宽为2--8\;GHz, 并且能够在E面和H面均实现\lk$\pm$45$^\circ$的扫描特性. 最后对该馈源阵列进行了样机加工和测试, 测试结果与仿真结果具有较好的一致性.

  • A Novel Soil Moisture Retrieval Algorithm for FY-3E GNOS-R Leveraging Multi-Angle Observations

    分类: 天文学 >> 天文学 提交时间: 2024-01-22

    摘要: Objective: Develop effective FY-3E GNOS-R algorithm for global soil moisture retrieval.
    Methods:
    1.Incorporate first-order vegetation model, consider density, and volume scattering.
    2.Use multi-angle GNOS-R observations, combine with SMAP data for optimization.
    3.Tailor algorithm for diverse surface conditions; parameterize surface roughness based on angle.
    Results: Achieve enhanced retrieval accuracy, RMSE: 0.0235, 0.0264, 0.0191 (g/cm3) for bare, low vegetation, and dense vegetation areas.
    Limitations: Limited to one month of data; further testing required for broader applicability.
    Conclusions: GNOS-R proves a robust tool, surpassing previous techniques for global soil moisture estimation.
     

  • A predictive model for regional zenith tropospheric delay correction

    分类: 天文学 >> 天文仪器与技术 提交时间: 2024-01-22 合作期刊: 《天文技术与仪器(英文)》

    摘要:The conventional zenith tropospheric delay (ZTD) model (known as the Saastamoinen model) does not consider seasonal variations affecting the delay, giving it low accuracy and stability. This may be improved with adjustments to account for annual and semi-annual variations. This method uses ZTD data provided by the Global Geodetic Observing System to analyze seasonal variations in the bias of the Saastamoinen model in Asia, and then constructs a model with seasonal variation corrections, denoted as SSA. To overcome the dependence of the model on in-situ meteorological parameters, the SSA+GPT3 model is formed by combining the SSA and GPT3 (global pressure-temperature) models. The results show that the introduction of annual and semi-annual variations can substantially improve the Saastamoinen model, yielding small and time-stable variations in bias and root mean square (RMS). In summer and autumn, the bias and RMS are noticeably smaller than those from the Saastamoinen model. In addition, the SSA model performs better in low-latitude and low-altitude areas, and bias and RMS decease with the increase of latitude or altitude. The prediction accuracy of the SSA model is also evaluated for external consistency. The results show that the accuracy of the SSA model (bias: −0.38 cm, RMS: 4.43 cm) is better than that of the Saastamoinen model (bias: 1.45 cm, RMS: 5.16 cm). The proposed method has strong applicability and can therefore be used for predictive ZTD correction across Asia.

  • End-to-end computational design for an EUV solar corona multispectral imager with stray light suppression

    分类: 天文学 >> 天文仪器与技术 提交时间: 2024-01-22 合作期刊: 《天文技术与仪器(英文)》

    摘要:An extreme ultraviolet solar corona multispectral imager can allow direct observation of high temperature coronal plasma, which is related to solar flares, coronal mass ejections and other significant coronal activities. This manuscript proposes a novel end-to-end computational design method for an extreme ultraviolet (EUV) solar corona multispectral imager operating at wavelengths near 100 nm, including a stray light suppression design and computational image recovery. To suppress the strong stray light from the solar disk, an outer opto-mechanical structure is designed to protect the imaging component of the system. Considering the low reflectivity (less than 70%) and strong-scattering (roughness) of existing extreme ultraviolet optical elements, the imaging component comprises only a primary mirror and a curved grating. A Lyot aperture is used to further suppress any residual stray light. Finally, a deep learning computational imaging method is used to correct the individual multi-wavelength images from the original recorded multi-slit data. In results and data, this can achieve a far-field angular resolution below 7", and spectral resolution below 0.05 nm. The field of view is ±3 R☉ along the multi-slit moving direction, where R☉ represents the radius of the solar disk. The ratio of the corona's stray light intensity to the solar center's irradiation intensity is less than 10−6 at the circle of 1.3 R☉.