Pub Date : 2024-09-18DOI: 10.1088/1674-4527/ad7364
Hao Fu, Peng Liu, Xuan Qi and Xue Mei
Stellar spectral classification is crucial in astronomical data analysis. However, existing studies are often limited by the uneven distribution of stellar samples, posing challenges in practical applications. Even when balancing stellar categories and their numbers, there is room for improvement in classification accuracy. This study introduces a Continuous Wavelet Transform using the Super Morlet wavelet to convert stellar spectra into wavelet images. A novel neural network, the Stellar Feature Network, is proposed for classifying these images. Stellar spectra from Large Sky Area Multi-Object Fiber Spectroscopic Telescope DR9, encompassing five equal categories (B, A, F, G, K), were used. Comparative experiments validate the effectiveness of the proposed methods and network, achieving significant improvements in classification accuracy.
{"title":"SFNet: Stellar Feature Network with CWT for Stellar Spectra Recognition","authors":"Hao Fu, Peng Liu, Xuan Qi and Xue Mei","doi":"10.1088/1674-4527/ad7364","DOIUrl":"https://doi.org/10.1088/1674-4527/ad7364","url":null,"abstract":"Stellar spectral classification is crucial in astronomical data analysis. However, existing studies are often limited by the uneven distribution of stellar samples, posing challenges in practical applications. Even when balancing stellar categories and their numbers, there is room for improvement in classification accuracy. This study introduces a Continuous Wavelet Transform using the Super Morlet wavelet to convert stellar spectra into wavelet images. A novel neural network, the Stellar Feature Network, is proposed for classifying these images. Stellar spectra from Large Sky Area Multi-Object Fiber Spectroscopic Telescope DR9, encompassing five equal categories (B, A, F, G, K), were used. Comparative experiments validate the effectiveness of the proposed methods and network, achieving significant improvements in classification accuracy.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"15 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142251990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.1088/1674-4527/ad74df
Kadirya Tursun, Jarken Esimbek, Willem Baan, Toktarkhan Komesh, Xindi Tang, Gang Wu, Jianjun Zhou, Yuxin He, Dalei Li, Dongdong Zhou and Yingxiu Ma
The observations of the Aquila Rift cloud complex at 23.708 and 115.271 GHz made using the Nanshan 26 m radio telescope and the 13.7 m millimeter-wavelength telescope are presented. We find that the CO(1 − 0) gas distribution is similar to the NH3 gas distribution in the Aquila Rift cloud complex. In some diffusion regions characterized by CO, we identified several dense clumps based on the distribution of detected ammonia molecular emission. Through the comparison of spectral line parameters for NH3, 13CO, and C18O, our study reveals that the line center velocities of the NH3, 13CO, and C18O lines are comparable and positively correlated, indicating that they originate from the same emission region. No significant correlation was identified for other parameters, including integrated intensity, line widths, main beam brightness temperature, as well as the column densities of NH3, 13CO, and C18O. The absolute difference in line-center velocities between the 13CO and NH3 lines is less than both the average line width of NH3 and that of 13CO. This suggests that there are no significant movements of NH3 clumps in relation to their envelopes. The velocity deviation is likely due to turbulent activity within the clumps.
{"title":"Comparison of NH3 and 12CO, 13CO, C18O Molecular Lines in the Aquila Rift Cloud Complex","authors":"Kadirya Tursun, Jarken Esimbek, Willem Baan, Toktarkhan Komesh, Xindi Tang, Gang Wu, Jianjun Zhou, Yuxin He, Dalei Li, Dongdong Zhou and Yingxiu Ma","doi":"10.1088/1674-4527/ad74df","DOIUrl":"https://doi.org/10.1088/1674-4527/ad74df","url":null,"abstract":"The observations of the Aquila Rift cloud complex at 23.708 and 115.271 GHz made using the Nanshan 26 m radio telescope and the 13.7 m millimeter-wavelength telescope are presented. We find that the CO(1 − 0) gas distribution is similar to the NH3 gas distribution in the Aquila Rift cloud complex. In some diffusion regions characterized by CO, we identified several dense clumps based on the distribution of detected ammonia molecular emission. Through the comparison of spectral line parameters for NH3, 13CO, and C18O, our study reveals that the line center velocities of the NH3, 13CO, and C18O lines are comparable and positively correlated, indicating that they originate from the same emission region. No significant correlation was identified for other parameters, including integrated intensity, line widths, main beam brightness temperature, as well as the column densities of NH3, 13CO, and C18O. The absolute difference in line-center velocities between the 13CO and NH3 lines is less than both the average line width of NH3 and that of 13CO. This suggests that there are no significant movements of NH3 clumps in relation to their envelopes. The velocity deviation is likely due to turbulent activity within the clumps.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"15 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142251989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.1088/1674-4527/ad7079
Alberto S. Betzler
This work analyzes the photometric data of the Oort spike comets C/2019 L3 (ATLAS) and C/2019 O3 (Palomar) obtained between 2016 and 2023 by the ATLAS network and the Belgian Olmen Observatory. The comets Palomar and ATLAS have a typical and unusually high activity level, respectively, based on the Afρ parameter corrected to phase angle zero at perihelion. The absolute magnitude of comets ATLAS and Palomar in the o-band is 4.71 ± 0.05 and 4.16 ± 0.02 respectively. The cometary activity of comets ATLAS and Palomar probably began at r > 13 au before perihelion and will end at r >14 au after perihelion, which means that they could remain active until the second half of 2026. The nucleus of comet ATLAS has a minimum radius of 7.9 km, and the nucleus of comet Palomar could be a little larger. The c − o colors of the comets ATLAS and Palomar are redder and bluer, respectively, at perihelion than the solar twin YBP 1194. These comets showed a bluish trend in the coma color with decreasing heliocentric distance. Comet Palomar probably had two outbursts after its perihelion, each releasing about 108 kg of dust. The slopes of the photometric profile of the comae of these comets were between 1 and 1.5, indicating a steady state during the observation campaign.
{"title":"A Study of the Comets with Large Perihelion Distances C/2019 L3 (ATLAS) and C/2019 O3 (Palomar)","authors":"Alberto S. Betzler","doi":"10.1088/1674-4527/ad7079","DOIUrl":"https://doi.org/10.1088/1674-4527/ad7079","url":null,"abstract":"This work analyzes the photometric data of the Oort spike comets C/2019 L3 (ATLAS) and C/2019 O3 (Palomar) obtained between 2016 and 2023 by the ATLAS network and the Belgian Olmen Observatory. The comets Palomar and ATLAS have a typical and unusually high activity level, respectively, based on the Afρ parameter corrected to phase angle zero at perihelion. The absolute magnitude of comets ATLAS and Palomar in the o-band is 4.71 ± 0.05 and 4.16 ± 0.02 respectively. The cometary activity of comets ATLAS and Palomar probably began at r > 13 au before perihelion and will end at r >14 au after perihelion, which means that they could remain active until the second half of 2026. The nucleus of comet ATLAS has a minimum radius of 7.9 km, and the nucleus of comet Palomar could be a little larger. The c − o colors of the comets ATLAS and Palomar are redder and bluer, respectively, at perihelion than the solar twin YBP 1194. These comets showed a bluish trend in the coma color with decreasing heliocentric distance. Comet Palomar probably had two outbursts after its perihelion, each releasing about 108 kg of dust. The slopes of the photometric profile of the comae of these comets were between 1 and 1.5, indicating a steady state during the observation campaign.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"16 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.1088/1674-4527/ad7078
Hui-Mei Feng, Zi-Huang Cao, Man I. Lam, Ran Li, Hao Tian, Xin Zhang, Peng Wei, Xin-Feng Li, Wei Wang, Hugh R. A. Jones, Mao-Yuan Liu and Chao Liu
In this study, we conducted simulations to find the geometric aberrations expected for images taken by the Main Survey Camera of the Chinese Space Station Telescope (CSST) due to its motion. As anticipated by previous work, our findings indicate that the geometric distortion of light impacts the focal plane's apparent scale, with a more pronounced influence as the size of the focal plane increases. Our models suggest that the effect consistently influences the pixel scale in both the vertical and parallel directions. The apparent scale variation follows a sinusoidal distribution throughout one orbital period. Simulations reveal that the effect is particularly pronounced in the center of the Galaxy and gradually diminishes along the direction of ecliptic latitude. At low ecliptic latitudes, the total aberration leads to about a 0.94 pixel offset (a 20 minute exposure) and a 0.26 pixel offset (a 300 s exposure) at the edge of the field of view. Appropriate processings for the geometric effect during the CSST pre- and post-observation phases are presented.
{"title":"The Velocity Aberration Effect of the CSST Main Survey Camera*","authors":"Hui-Mei Feng, Zi-Huang Cao, Man I. Lam, Ran Li, Hao Tian, Xin Zhang, Peng Wei, Xin-Feng Li, Wei Wang, Hugh R. A. Jones, Mao-Yuan Liu and Chao Liu","doi":"10.1088/1674-4527/ad7078","DOIUrl":"https://doi.org/10.1088/1674-4527/ad7078","url":null,"abstract":"In this study, we conducted simulations to find the geometric aberrations expected for images taken by the Main Survey Camera of the Chinese Space Station Telescope (CSST) due to its motion. As anticipated by previous work, our findings indicate that the geometric distortion of light impacts the focal plane's apparent scale, with a more pronounced influence as the size of the focal plane increases. Our models suggest that the effect consistently influences the pixel scale in both the vertical and parallel directions. The apparent scale variation follows a sinusoidal distribution throughout one orbital period. Simulations reveal that the effect is particularly pronounced in the center of the Galaxy and gradually diminishes along the direction of ecliptic latitude. At low ecliptic latitudes, the total aberration leads to about a 0.94 pixel offset (a 20 minute exposure) and a 0.26 pixel offset (a 300 s exposure) at the edge of the field of view. Appropriate processings for the geometric effect during the CSST pre- and post-observation phases are presented.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"11 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.1088/1674-4527/ad707a
Xiaoying Guo, Wasim Iqbal, Qiang Chang and Xiao-Hu Li
We use microscopic Monte Carlo simulation techniques to investigate the impact of H2 diffusion energy on the recombination efficiency of H2 on interstellar dust grain surfaces under diffuse and translucent cloud conditions. We constructed five models representing different possible conditions encountered by adsorbed H and H2 on interstellar dust grains. We implemented adsorption sites with multiple binding energies for surface species; the Encounter-Desorption mechanism was also included. The study focused on silicate surfaces in diffuse clouds and water ice surfaces in translucent clouds. The results show that the recombination efficiency of H2 on dust surfaces decreases as H2 diffusion energy increases. An interesting finding of this work is that considering different binding sites for H and H2 gives rise to multiple steady phases, during which the recombination efficiency remains constant with a change in H2 diffusion energy.
我们利用微观蒙特卡洛模拟技术研究了在扩散云和半透明云条件下，H2 扩散能对星际尘粒表面 H2 重组效率的影响。我们构建了五个模型，分别代表星际尘粒上吸附的 H 和 H2 可能遇到的不同条件。我们为表面物种设置了具有多种结合能的吸附位点；还包括相遇-解吸机制。研究重点是弥漫云中的硅酸盐表面和半透明云中的水冰表面。结果表明，尘埃表面的 H2 重组效率随着 H2 扩散能的增加而降低。这项工作的一个有趣发现是，考虑到 H 和 H2 的不同结合位点，会产生多个稳定阶段，在此期间，随着 H2 扩散能的变化，重组效率保持不变。
{"title":"Understanding the Impact of H2 Diffusion Energy on the Formation Efficiency of H2 on the Interstellar Dust Grain Surface","authors":"Xiaoying Guo, Wasim Iqbal, Qiang Chang and Xiao-Hu Li","doi":"10.1088/1674-4527/ad707a","DOIUrl":"https://doi.org/10.1088/1674-4527/ad707a","url":null,"abstract":"We use microscopic Monte Carlo simulation techniques to investigate the impact of H2 diffusion energy on the recombination efficiency of H2 on interstellar dust grain surfaces under diffuse and translucent cloud conditions. We constructed five models representing different possible conditions encountered by adsorbed H and H2 on interstellar dust grains. We implemented adsorption sites with multiple binding energies for surface species; the Encounter-Desorption mechanism was also included. The study focused on silicate surfaces in diffuse clouds and water ice surfaces in translucent clouds. The results show that the recombination efficiency of H2 on dust surfaces decreases as H2 diffusion energy increases. An interesting finding of this work is that considering different binding sites for H and H2 gives rise to multiple steady phases, during which the recombination efficiency remains constant with a change in H2 diffusion energy.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"37 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.1088/1674-4527/ad6fe6
Shiliang Zhang, Guanwen Fang, Jie Song, Ran Li, Yizhou Gu, Zesen Lin, Chichun Zhou, Yao Dai and Xu Kong
Most existing star-galaxy classifiers depend on the reduced information from catalogs, necessitating careful data processing and feature extraction. In this study, we employ a supervised machine learning method (GoogLeNet) to automatically classify stars and galaxies in the COSMOS field. Unlike traditional machine learning methods, we introduce several preprocessing techniques, including noise reduction and the unwrapping of denoised images in polar coordinates, applied to our carefully selected samples of stars and galaxies. By dividing the selected samples into training and validation sets in an 8:2 ratio, we evaluate the performance of the GoogLeNet model in distinguishing between stars and galaxies. The results indicate that the GoogLeNet model is highly effective, achieving accuracies of 99.6% and 99.9% for stars and galaxies, respectively. Furthermore, by comparing the results with and without preprocessing, we find that preprocessing can significantly improve classification accuracy (by approximately 2.0% to 6.0%) when the images are rotated. In preparation for the future launch of the China Space Station Telescope (CSST), we also evaluate the performance of the GoogLeNet model on the CSST simulation data. These results demonstrate a high level of accuracy (approximately 99.8%), indicating that this model can be effectively utilized for future observations with the CSST.
{"title":"Preparation for CSST: Star-galaxy Classification using a Rotationally Invariant Supervised Machine Learning Method","authors":"Shiliang Zhang, Guanwen Fang, Jie Song, Ran Li, Yizhou Gu, Zesen Lin, Chichun Zhou, Yao Dai and Xu Kong","doi":"10.1088/1674-4527/ad6fe6","DOIUrl":"https://doi.org/10.1088/1674-4527/ad6fe6","url":null,"abstract":"Most existing star-galaxy classifiers depend on the reduced information from catalogs, necessitating careful data processing and feature extraction. In this study, we employ a supervised machine learning method (GoogLeNet) to automatically classify stars and galaxies in the COSMOS field. Unlike traditional machine learning methods, we introduce several preprocessing techniques, including noise reduction and the unwrapping of denoised images in polar coordinates, applied to our carefully selected samples of stars and galaxies. By dividing the selected samples into training and validation sets in an 8:2 ratio, we evaluate the performance of the GoogLeNet model in distinguishing between stars and galaxies. The results indicate that the GoogLeNet model is highly effective, achieving accuracies of 99.6% and 99.9% for stars and galaxies, respectively. Furthermore, by comparing the results with and without preprocessing, we find that preprocessing can significantly improve classification accuracy (by approximately 2.0% to 6.0%) when the images are rotated. In preparation for the future launch of the China Space Station Telescope (CSST), we also evaluate the performance of the GoogLeNet model on the CSST simulation data. These results demonstrate a high level of accuracy (approximately 99.8%), indicating that this model can be effectively utilized for future observations with the CSST.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"31 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.1088/1674-4527/ad74dd
Xu-Qiao Wang, Lan Du, Zhong-Kai Zhang, Ze-Jun Liu and Hao Xiang
High-precision polar motion prediction is of great significance for deep space exploration and satellite navigation. Polar motion is affected by a variety of excitation factors, and nonlinear prediction methods are more suitable for polar motion prediction. In order to explore the effect of deep learning in polar motion prediction. This paper proposes a combined model based on empirical wavelet transform (EWT), Convolutional Neural Networks (CNN) and Long Short Term Memory (LSTM). By training and forecasting EOP 20C04 data, the effectiveness of the algorithm is verified, and the performance of two forecasting strategies in deep learning for polar motion prediction is explored. The results indicate that recursive multi-step prediction performs better than direct multi-step prediction for short-term forecasts within 15 days, while direct multi-step prediction is more suitable for medium and long-term forecasts. In the 365 days forecast, the mean absolute error of EWT-CNN-LSTM in the X direction and Y direction is 18.25 mas and 15.78 mas, respectively, which is 23.5% and 16.2% higher than the accuracy of Bulletin A. The results show that the algorithm has a good effect in medium and long term polar motion prediction.
高精度极地运动预测对深空探测和卫星导航具有重要意义。极地运动受多种激励因素影响，非线性预测方法更适合极地运动预测。为了探索深度学习在极地运动预测中的效果。本文提出了一种基于经验小波变换（EWT）、卷积神经网络（CNN）和长短期记忆（LSTM）的组合模型。通过对 EOP 20C04 数据的训练和预测，验证了该算法的有效性，并探讨了深度学习中两种预测策略在极地运动预测中的性能。结果表明，在 15 天以内的短期预报中，递归多步预报的性能优于直接多步预报，而直接多步预报更适合中长期预报。在 365 天的预报中，EWT-CNN-LSTM 在 X 方向和 Y 方向的平均绝对误差分别为 18.25 mas 和 15.78 mas，分别比 Bulletin A 的精度高 23.5%和 16.2%。
{"title":"Leveraging the Empirical Wavelet Transform in Combination with Convolutional LSTM Neural Networks to Enhance the Accuracy of Polar Motion Prediction","authors":"Xu-Qiao Wang, Lan Du, Zhong-Kai Zhang, Ze-Jun Liu and Hao Xiang","doi":"10.1088/1674-4527/ad74dd","DOIUrl":"https://doi.org/10.1088/1674-4527/ad74dd","url":null,"abstract":"High-precision polar motion prediction is of great significance for deep space exploration and satellite navigation. Polar motion is affected by a variety of excitation factors, and nonlinear prediction methods are more suitable for polar motion prediction. In order to explore the effect of deep learning in polar motion prediction. This paper proposes a combined model based on empirical wavelet transform (EWT), Convolutional Neural Networks (CNN) and Long Short Term Memory (LSTM). By training and forecasting EOP 20C04 data, the effectiveness of the algorithm is verified, and the performance of two forecasting strategies in deep learning for polar motion prediction is explored. The results indicate that recursive multi-step prediction performs better than direct multi-step prediction for short-term forecasts within 15 days, while direct multi-step prediction is more suitable for medium and long-term forecasts. In the 365 days forecast, the mean absolute error of EWT-CNN-LSTM in the X direction and Y direction is 18.25 mas and 15.78 mas, respectively, which is 23.5% and 16.2% higher than the accuracy of Bulletin A. The results show that the algorithm has a good effect in medium and long term polar motion prediction.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"31 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.1088/1674-4527/ad6ee1
Arina Mitrofanova, Vladimir Dyachenko, Anatoly Beskakotov, Yuri Balega, Alexander Maksimov and Denis Rastegaev
The results of seventeen years of speckle interferometric monitoring of seven objects (Chara 122Aa, GJ 3010, HIP 1987, GJ 3076, HIP 11253, HIP 11352, and HIP 14929) are presented. Observational data were obtained at the 6 m Big Telescope Alt-azimuthal Special Astrophysical Observatory of the Russian Academy of Science (BTA SAO RAS) from 2007 to the present. Analysis of previously published and new measurements made it possible to construct completely new orbits for Chara 122Aa, HIP 11253, and HIP 14929. The orbit of GJ 3076 cannot be constructed accurately due to the large influence of the weights assigned to the measurements. The resulting orbital solutions are classified based on a grading scheme suggested by W.I. Hartkopf, B.D. Mason and C.E. Worley; most orbits are “definitive” (Grade 1). The mass sums and masses of components calculated by two independent methods using Hipparcos and Gaia DR2 and DR3 parallaxes were compared for the objects under study.
{"title":"Long-term Speckle Interferometric Monitoring of Binary Systems: 2007–2023 Positional Measurements and Orbits of Seven Objects","authors":"Arina Mitrofanova, Vladimir Dyachenko, Anatoly Beskakotov, Yuri Balega, Alexander Maksimov and Denis Rastegaev","doi":"10.1088/1674-4527/ad6ee1","DOIUrl":"https://doi.org/10.1088/1674-4527/ad6ee1","url":null,"abstract":"The results of seventeen years of speckle interferometric monitoring of seven objects (Chara 122Aa, GJ 3010, HIP 1987, GJ 3076, HIP 11253, HIP 11352, and HIP 14929) are presented. Observational data were obtained at the 6 m Big Telescope Alt-azimuthal Special Astrophysical Observatory of the Russian Academy of Science (BTA SAO RAS) from 2007 to the present. Analysis of previously published and new measurements made it possible to construct completely new orbits for Chara 122Aa, HIP 11253, and HIP 14929. The orbit of GJ 3076 cannot be constructed accurately due to the large influence of the weights assigned to the measurements. The resulting orbital solutions are classified based on a grading scheme suggested by W.I. Hartkopf, B.D. Mason and C.E. Worley; most orbits are “definitive” (Grade 1). The mass sums and masses of components calculated by two independent methods using Hipparcos and Gaia DR2 and DR3 parallaxes were compared for the objects under study.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"6 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we perform the detailed modeling for the light curves (LCs) of PTF 10iuv which is a calcium-rich (Ca-rich) supernova (SN) to constrain the physical properties of its ejecta and the energy sources, as well as the explosion mechanism. We find that the 56Ni model and the 56Ni plus circumstellar interaction model fail to explain the LCs, while the four-element (56Ni, 48Cr, 52Fe, and 44Ti) model can account for the LCs. The ejecta mass of PTF 10iuv derived by the model ( M⊙) is consistent with that of the merger of a sub-Chandrasekhar mass white dwarf. The early-time LCs were mainly powered by 56Ni whose mass is ∼0.03 M⊙, while the contributions of 48Cr and 52Fe can be neglected. The derived 44Ti mass (∼0.25 M⊙) is ∼1.8 times the upper limit of the derived 44Ti mass of Ca-rich SN 2005E. We suggest that subtracting the contributions of the host-galaxy, which are unknown, and including the flux from other long-lived elements (e.g., 57Co, 55Fe, 60Co) can reduce the amount of 44Ti, and that this value can be regarded as an upper limit.
{"title":"The Energy Sources and the Explosion Mechanism of Ca-rich Supernova PTF 10iuv","authors":"Qiu-Ping Huang, 秋萍 黄, Shan-Qin Wang, 善钦 王, Tao Wang, 涛 王, Wen-Pei Gan, 文沛 甘, Deng-Wang Shi, 登旺 石, Liu-Yi Wang, 浏毅 王, En-Wei Liang and 恩维 梁","doi":"10.1088/1674-4527/ad6bd5","DOIUrl":"https://doi.org/10.1088/1674-4527/ad6bd5","url":null,"abstract":"In this paper, we perform the detailed modeling for the light curves (LCs) of PTF 10iuv which is a calcium-rich (Ca-rich) supernova (SN) to constrain the physical properties of its ejecta and the energy sources, as well as the explosion mechanism. We find that the 56Ni model and the 56Ni plus circumstellar interaction model fail to explain the LCs, while the four-element (56Ni, 48Cr, 52Fe, and 44Ti) model can account for the LCs. The ejecta mass of PTF 10iuv derived by the model ( M⊙) is consistent with that of the merger of a sub-Chandrasekhar mass white dwarf. The early-time LCs were mainly powered by 56Ni whose mass is ∼0.03 M⊙, while the contributions of 48Cr and 52Fe can be neglected. The derived 44Ti mass (∼0.25 M⊙) is ∼1.8 times the upper limit of the derived 44Ti mass of Ca-rich SN 2005E. We suggest that subtracting the contributions of the host-galaxy, which are unknown, and including the flux from other long-lived elements (e.g., 57Co, 55Fe, 60Co) can reduce the amount of 44Ti, and that this value can be regarded as an upper limit.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"208 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-15DOI: 10.1088/1674-4527/ad6ee2
Bo-Lin Qin, 柏霖 覃, Jing Li, 静 黎, Wei-Jian Lu and 伟坚 陆
We investigate the relationship between the variability of broad absorption lines (BALs) or narrow absorption lines (NALs) and that of continuum using a data set of two-epoch SDSS spectra containing 134 C iv NAL-BAL pairs. Our analysis reveals an anti-correlation between the fractional equivalent width (EW) variations in NALs (or BALs) and the fractional flux variations of the continuum, with Spearman rank correlation coefficients of r = −0.47 (p = 1E-08) and r = −0.58 (p = 1E-13), respectively. In addition, we find a positive correlation between the fractional EW variations in NALs and BALs (r = 0.72, p = 1E-22), and derive a regression equation ΔEWNAL/〈EWNAL〉 = 0.803ΔEWBAL/〈EWBAL〉 + 0.008, with an intrinsic scatter of 0.14. These results suggest that the variability in the ionizing continuum may play a significant role in the observed changes in C iv NALs and BALs, supporting the idea of photoionization-driven variability. The co-variability between C iv NALs and BALs may imply that they originate from outflows with similar physical conditions.
我们利用包含 134 对 C iv NAL-BAL 的双波长 SDSS 光谱数据集，研究了宽吸收线（BAL）或窄吸收线（NAL）的变化与连续波的变化之间的关系。我们的分析表明，NAL（或 BAL）的分数等效宽度（EW）变化与连续波的分数通量变化之间存在反相关关系，斯皮尔曼秩相关系数分别为 r = -0.47 (p = 1E-08) 和 r = -0.58 (p = 1E-13)。此外，我们还发现 NALs 和 BALs 的分数 EW 变化之间存在正相关（r = 0.72，p = 1E-22），并推导出回归方程 ΔEWNAL/〈EWNAL〉 = 0.803ΔEWBAL/〈EWBAL〉 + 0.008，其内在散度为 0.14。这些结果表明，电离连续相的变化可能在观测到的 C iv NALs 和 BALs 变化中起了重要作用，支持了光离子化驱动变化的观点。C iv NALs 和 BALs 之间的共同可变性可能意味着它们源自物理条件相似的外流。
{"title":"Co-variability Between the Broad Absorption Lines and Narrow Absorption Lines","authors":"Bo-Lin Qin, 柏霖 覃, Jing Li, 静 黎, Wei-Jian Lu and 伟坚 陆","doi":"10.1088/1674-4527/ad6ee2","DOIUrl":"https://doi.org/10.1088/1674-4527/ad6ee2","url":null,"abstract":"We investigate the relationship between the variability of broad absorption lines (BALs) or narrow absorption lines (NALs) and that of continuum using a data set of two-epoch SDSS spectra containing 134 C iv NAL-BAL pairs. Our analysis reveals an anti-correlation between the fractional equivalent width (EW) variations in NALs (or BALs) and the fractional flux variations of the continuum, with Spearman rank correlation coefficients of r = −0.47 (p = 1E-08) and r = −0.58 (p = 1E-13), respectively. In addition, we find a positive correlation between the fractional EW variations in NALs and BALs (r = 0.72, p = 1E-22), and derive a regression equation ΔEWNAL/〈EWNAL〉 = 0.803ΔEWBAL/〈EWBAL〉 + 0.008, with an intrinsic scatter of 0.14. These results suggest that the variability in the ionizing continuum may play a significant role in the observed changes in C iv NALs and BALs, supporting the idea of photoionization-driven variability. The co-variability between C iv NALs and BALs may imply that they originate from outflows with similar physical conditions.","PeriodicalId":54494,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"28 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142268659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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