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关键词： binaries: eclipsing   binaries: close   stars: fundamental parameters   methods: data analysis   stars: individual: (Seven Contact Binary Stars)  

摘要： This is the first in-depth study of seven total-eclipse W Ursae Majoris-type contact binary systems using photometric light curves. The ground-based observations were conducted with four observatories in the Northern and Southern hemispheres. We also used the Transiting Exoplanet Survey Satellite for four target systems. We presented the analysis of orbital period variations of six systems and found that they display parabolic variations. The material transfer rates between the stars of the systems were calculated. Also, the results show that four systems have a long-term increase, while two have a long-term decrease in their orbital periods. We analysed light curves using the PHysics Of Eclipsing BinariEs python code and the Markov chain Monte Carlo algorithm to estimate different parameters of target systems and their uncertainties. Six of the target systems required the addition of a cold or hot star-spot. We estimated absolute parameters using the empirical relationship between the orbital period and the semimajor axis (P-a). According to each component's effective temperature and mass, it was recognized that the studied systems are W subtype. We examined the dynamic stability of two targets, which were low mass ratio contact binary systems. We also showed the evolution of stars in the M-R and M-L diagrams. Finally, we showed that the hotter stars in contact systems have a temperature difference of less than approximate to 400 K compared to the Gaia Data Release 3 temperature report.

关键词： dose calculation   dose verification   dual-layer MLC   ELM   VMAT  

摘要： PurposeThe dual-layer multileaf collimator (MLC) in Halcyon adds complexities to the dose calculation process owing to the variability of dosimetric characteristics with leaf motion. Recently, an enhanced leaf model (ELM) was developed to refine the MLC model in the Eclipse treatment planning system. This study investigates the performance of the Halcyon ELM by verifying doses for simple slit fields and volumetric modulated arc therapy (VMAT) *** and methodsDose calculations were performed with Acuros XB using the ELM. To commission the leaf-tip model, the dosimetric leaf gap (DLG) was calculated (referred to as DLGELM) and compared with Halcyon measurements. The DLGs were assessed under conditions both with and without leaf trailing between the MLC layers. The tongue-and-groove (TG) model was evaluated by comparing leaf-edge profiles and the outputs of the asynchronous sweeping gap. Furthermore, eleven VMAT plans were validated against chamber doses and Delta4 *** demonstrated variation between layers, measuring 0.42 mm for the proximal layer and 0.23 mm for the distal layer, and showed a correspondence with the measured DLGs in 0.1 mm. Additionally, ELM reduced the discrepancy between calculated and measured DLGs when accounting for leaf trailing. In the TG model test, ELM calculations successfully mirrored the measured leaf-edge profiles. Moreover, the median dose difference between ELM calculations and chamber doses was -0.8% in asynchronous sweeping gaps. In the VMAT dose verification, the incorporation of ELM enhanced the target dose and resulted in a gamma pass rate (2%/2 mm) exceeding 95%.ConclusionHalcyon ELM considerably improved the accuracy of simulating actual leaf-tip transmission, both with and without leaf trailing, and it effectively accounted for the additional blocking caused by TG design. Furthermore, the introduction of ELM in Eclipse considerably enhanced the VMAT dose calculation. ELM addresses the limitation

摘要： We present high-resolution emission spectroscopy observations of the ultra-hot Jupiter MASCARA-1b with CRIRES+ in the K-band, covering the post-eclipse phases of its orbit. These observations complement previously published pre-eclipse data. The stellar and telluric features were removed using SysRem, and the planetary signal was analysed with the cross-correlation technique. After confirming the presence of chemical species in our atmospheric model, we combined the pre- and post-eclipse datasets for a joint analysis. By employing a Bayesian retrieval framework, this joint retrieval enabled us to constrain the spatially varying temperature-pressure (T-P) profile and atmospheric carbon-to-oxygen (C/O) ratio. We detected strong emission signatures of CO and H2O in the post-eclipse and combined datasets. While a well-mixed retrieval model results in a super-solar C/O, allowing for vertically varying chemistry yields C/O values consistent with solar. The retrieved parameters are not only consistent across the datasets but also across different chemical regimes. We did not identify any significant velocity shifts between the detected species or across the datasets, which could otherwise serve as proxies for possible atmospheric dynamics. We also explored phase dependence through the model scaling factor and found no substantial changes in atmospheric properties throughout the observed phases. Due to strong degeneracies between the temperature gradient and chemical abundances, our retrieved temperatures are broadly consistent with either a full redistribution of heat or strong day-night contrasts. While this complicates direct comparisons with recent Spitzer phase curve analyses suggesting inefficient recirculation, we find no clear evidence of spatial variation in the chemical or temperature structure of MASCARA-1b from pre- to post-eclipse, nor temporal variation over ≈2 years.

关键词： Atmospheric chemistry  

摘要： Aims. We present high-resolution emission spectroscopy observations of the ultra-hot Jupiter MASCARA-1b with CRIRES+ in the K-band, covering the post-eclipse phases of the planet’s orbit. These observations complement previously published pre-eclipse data. Methods. The stellar and telluric features were removed from the data using the SysRem algorithm, and the planetary signal was analysed with the cross-correlation technique. After confirming the presence of chemical species in our atmospheric model, we combined the pre- and post-eclipse datasets for a joint analysis. By employing a Bayesian retrieval framework with various parametrisations, this joint retrieval enabled us to constrain the spatially varying temperature-pressure (T-P) profile and the atmospheric carbon-to-oxygen (C/O) ratio. Results. We detected strong emission signatures of CO and H2O in the post-eclipse and the combined datasets. A well-mixed retrieval model results in a super-solar C/O, whereas allowing for vertically varying chemistry by incorporating a chemical model results in C/O values consistent with solar within ≈1.1σ. The retrieved parameters are not only consistent across the datasets but also across different chemical regimes. We did not identify any significant velocity shifts between the detected species or across the datasets, which could otherwise serve as proxies for possible atmospheric dynamics. We also explored potential phase dependence through the model scaling factor and found no substantial changes in the atmospheric properties throughout the observed phases. Conclusions. Due to strong degeneracies between the temperature gradient and chemical abundances, our retrieved temperatures are broadly consistent with either a full redistribution of heat or strong day-night contrasts. While this complicates direct comparisons with recent Spitzer phase curve analyses suggesting inefficient recirculation, we find no clear evidence of spatial variation in the chemical or temperature str

摘要： 2024年10月，《中国学术期刊（光盘版）》电子杂志社有限公司、中国科学文献计量评价研究中心联合发布《中国学术期刊影响因子年报（人文社会科学·2024版）》。年报数据显示，《数量经济技术经济研究》的学术影响力保持持续提升态势，影响因子的各项指标再创历史新高。2023年，本刊复合影响因子为16.829，相较2022年提升27.72%；综合影响因子为12.760，相较2022年提升39.35%。在“经济学理论”类期刊中首次跃升至第二位。

关键词： GNSS   Ionospheric sounding   Low latitudes   O/N2   Solar eclipse   Solarimetric station  

摘要： The study reports results of the unique experiment during the annular solar eclipse of October 14, 2023, over in Mexico. Vertical and oblique sounding, satellite, magnetometer, solarimetric and GNSS-derived data were used. Eclipse parameters were reconstructed at different heights. The southeastward eclipse penumbra movement intensified the electron density (Ne) decrease caused by the regular byte- out. The westward movement of the ionospheric structures with time (diurnal Ne maximum and the poleward side of EIA) related to the midday hour mitigated this decrease to some extent. The influence of the poleward side of the northern EIA crest on the eclipse day was noticeable in latitudes lower similar to 21 degrees N. The largest decrease of foF2 by 2.67 MHz (21.89 %) and F2MOF by 2.49 MHz (16.6 %) were observed 67 and 75 min after the eclipse maximal phase, respectively. Two-hop mode propagation was affected earlier and stronger than one-hop. F1 layer was absent at some hours due to the decreased ionization flux. Es layer was partially absent and, when appeared, showed its decreased electron concentration. The absorption level decreased due to the weakened solar ionization flux. similar to(43-45)% of the electron density decrease registered with vTEC occurred above the F2 layer and was faster than in the F2 layer because the eclipse passage tangential velocity was higher at the higher heights. The Ne recovery was much slower than its decrease and with almost the same rate of change in F2 layer and the above heights. The maximal Sun's and Moon's discs Overlap was not the leading factor in vTEC