The Square Kilometre Array (SKA) has entered the construction and commissioning phase. However, the storage and processing of its massive data remain one of the critical challenges that need to be addressed. The construction and operation of the SKA Regional Center (SRC) also heavily rely on efficient data storage and management solutions. To explore the key issues in SKA data storage and management in depth, this paper systematically investigates the development history of Measurement Set (MS) technology, the technical characteristics of its various versions, and their limitations in SKA applications. This paper particularly analyzes the technological innovations in Measurement Set Version 4 (MSV4) and its potential impacts on SKA data management and research. The study indicates that MSV4, by introducing features such as self-description, modular architecture, and efficient storage, is expected to effectively alleviate the bottlenecks in SKA data storage and processing. If MSV4 becomes the standard for SKA data storage, it will significantly influence the construction of SRCs in China and SKA scientific research. Therefore, it is essential to closely monitor the technological development of MSV4 at this stage and to proactively prepare relevant technological reserves to ensure the successful development, upgrading, and transformation of SRC scientific application pipelines and data processing software for SKA scientific research.
Asteroids are celestial bodies widely present within the solar system. Light curves, which are plots of brightness variation over time obtained from continuous observations of an asteroid, contain information related to its orbital, rotational, shape, and thermophysical parameters. Through light curves, shape inversion of asteroids can be performed to investigate the relationship between the characteristics of light curves and the asteroid's rotational state. Firstly, by comprehensively considering the shape, rotational state, and phase angle of the asteroid, a photometric model is established to simulate and generate asteroid light curves. Based on the triaxial ellipsoid model, the influence of various parameters on light curves is analyzed, and the variations in light curves under principal-axis rotation and non-principal-axis rotation are studied, thereby obtaining the correspondence between light curve features and rotational and shape parameters. Subsequently, parameter fitting of asteroid light curves is performed using both the triaxial ellipsoid model and the convex polyhedron model to invert and obtain the rotational and shape parameters.
The optical system of the balloon-borne coronagraph typically adopts a small focal ratio design, leading to a slender tube structure that is highly sensitive to fluctuations in ambient temperature. To ensure stable operation under the low-temperature and low-pressure conditions of near-space, this study developed a high-precision thermal control system. The system comprises 12 sets of independently regulated temperature control units, utilizing thermistors as sensors, along with thin-film heaters and a PID (Proportional-Integral-Derivative) control algorithm, to accurately maintain the mirror tube temperature within (−5±3) ∘C. By exploiting the differential thermal contraction properties between aluminum alloy and optical materials, the system effectively eliminates structural gaps and mitigates thermal deformation, while an active focusing mechanism compensates for focal shift caused by temperature variations. Through systematic analysis of the structural characteristics of the coronagraph and its operating environment, a heat transfer model specific to near-space conditions was established, identifying the key factors influencing the system temperature, and then a thermal control scheme combining multi-layer insulation and active heating was proposed. On 4 October 2022, a successful flight experiment was conducted in Da Qaidam, Qinghai Province, where the system operated at an altitude of 30 km, acquiring valuable observational data. The recovered data indicates that the temperature control system operates stably, with the temperature fluctuation of the coronagraph tube controlled within the design range. This effectively ensures the normal of the coronagraph in extreme environments, and provides an important technical reference for future similar missions.
As crucial cosmic distance indicator, the RR Lyrae star (RRL) with RRab type plays a significant role in studying the dynamical properties of the Milky Way. However, due to their pulsating nature, the observed radial velocities of RRab stars contain not only the systemic heliocentric velocity but also a substantial component from the stellar pulsation, posing a challenge for accurate kinematic measurements. In this study, we use medium-resolution spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) to construct radial velocity curve templates for RRab stars based on the Mg Ib and Hα absorption lines, with the aim of improving the accuracy of their derived heliocentric radial velocities. Comparative analysis with existing templates shows that the radial velocity curve templates developed in this work yield consistent velocity estimates, with the standard deviations of the resulting heliocentric radial velocities being smaller than 5km·s−1. The templates presented here are well-suited for deriving reliable heliocentric radial velocities for RRab stars observed by LAMOST.
Thanks to recent advancements in observational technology, significant progress has been made in the search for open clusters. Among these, binary open clusters have become a key focus of cluster studies due to their unique properties and complex interactions. The open clusters NGC 2232 and Tian 2, which are located at a very close distance from each other, are considered a binary cluster system. Observations show that these two clusters have very young and similar ages (approximately 30–40 Myr). There is a structure formed by stars with a length exceeding 200 pc near the binary star cluster, which is called the “Stellar Snake”. Through a series of high-precision N-body dynamical simulations (N: the number of bodies), the formation of the stellar snake has been dynamically modeled. The simulation results indicate that the two clusters are currently in a non-dynamically bound state, and it remains uncertain whether they were bound at the time of their formation. If the system is initially considered unbound, the two clusters show no significant mass loss after independently evolving for 100 Myr, and their mass loss rate is not significantly higher than that of a single open cluster in the Milky Way under tidal stripping. In contrast, if the two clusters were initially bound at birth and evolved together for 100 Myr, the tidal effects from mutual orbital motion within this bound system significantly accelerated the mass loss of the clusters. As a result, the stripped stars formed a larger tidal structure, but the tidal stream did not effectively form a structure resembling the stellar snake with a span over 200 pc. Additionally, considering the observed stellar snake as a one-sided structure, it does not match the symmetric tidal arms and tails that would be expected from tidal interactions. Therefore, the stellar snake is not likely to be a product of tidal effects, but rather a formation mechanism more consistent with the collapse of primordial gas along a filamentary structure.
