Frontiers in Astronomy and Space Sciences最新文献

Investigation of a W UMa-type contact binary GZ And in a physical triple system 研究物理三重系统中的 W UMa 型接触双星 GZ And

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-15 DOI: 10.3389/fspas.2024.1402031

Lin-Qiao Jiang, Jie Zheng

{"title":"Investigation of a W UMa-type contact binary GZ And in a physical triple system","authors":"Lin-Qiao Jiang, Jie Zheng","doi":"10.3389/fspas.2024.1402031","DOIUrl":"https://doi.org/10.3389/fspas.2024.1402031","url":null,"abstract":"GZ And is a variable star within the visually observed multiple-star system ADS 1693. Recent observations have yielded new light curves for GZ And, obtained using the Xinglong 85-cm telescope and the Transiting Exoplanet Survey Satellite (TESS) satellite. These light curves, along with radial velocity curves, were analyzed simultaneously to ascertain the fundamental physical parameters of GZ And’s components. The findings indicate that the primary star has a mass of M1 = 0.57 (4)M⊙, radius of R1 = 0.75 (2)R⊙, and luminosity of L1 = 0.42 (2)L⊙. The secondary star is characterized by a mass of M2 = 1.19 (9)M⊙, radius of R2 = 1.04 (3)R⊙, and luminosity of L2 = 0.63 (3)L⊙. Their orbital separation is determined to be a = 2.30 (6)R⊙. An analysis of the accumulated times of light minima reveals that GZ And is undergoing orbital period variations at a rate of dP/dt = −7.58 (7) × 10−8day ⋅ year−1, likely due to mass transfer from the more massive component to its lighter counterpart at a rate of dM2/dt = −9.06 (8) × 10−8M⊙⋅ year−1. Additionally, distance measurements for the component stars in ADS 1693, derived from Gaia DR3 astrometric data, suggest that ADS 1693A (GZ And) and ADS 1693B are gravitationally bound and likely originated from the same molecular cloud, sharing similar ages. This evidence supports the classification of GZ And as a W UMa-type contact binary within a physically associated triple system.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"42 49","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141644985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Probing turbulence in solar flares from SDO/AIA emission lines 从 SDO/AIA 发射线探测太阳耀斑中的湍流

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-11 DOI: 10.3389/fspas.2024.1383746

Xiaoyan Xie, Gang Li, Katharine K. Reeves, Tingyu Gou

{"title":"Probing turbulence in solar flares from SDO/AIA emission lines","authors":"Xiaoyan Xie, Gang Li, Katharine K. Reeves, Tingyu Gou","doi":"10.3389/fspas.2024.1383746","DOIUrl":"https://doi.org/10.3389/fspas.2024.1383746","url":null,"abstract":"Multiple pieces of evidence have revealed the important role of turbulence in physical processes in solar eruptions, from particle acceleration to the suppression of conductive cooling. Radio observations of density variation have established a Kolmogorov-like spectrum for solar wind density disturbance. Close to the Sun, measurements from extreme ultraviolet (EUV) bands have been used to examine turbulence in the solar atmosphere. The Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory (SDO/AIA) has been frequently used for diagnosing plasma properties due to its complex coverage of temperature response. We compute structure functions (SFs) using SDO/AIA emission measurements for two example of plasma sheets. With the relationship of v ∼ b ∼ δn and δI∼δ(n0+δn)2∼δn (v, b, δn, and δI are turbulent velocity, magnetic field, number density, and intensity, respectively, and n0 is the background density), SFs of δI can be regarded as a proxy for those of the turbulent v and b fields in the plasma sheet. We show that by properly accounting for the radial dependence of the emission line intensity, an SF method is capable of probing the presence of turbulence from SDO/AIA emission lines. Compared to in situ observations, performing SFs on EUV emissions is advantageous in studying turbulence behavior in the wave-vector space, and it opens a new window for investigating turbulence from massive SDO/AIA observations.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"54 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141658280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical model of the QiTai radio Telescope PAF receiver signal and simulation of interference mitigation 奇台射电望远镜 PAF 接收机信号的数值模型和干扰缓解模拟

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-10 DOI: 10.3389/fspas.2024.1392970

Peng Wu, Jian Li, Mao-Zheng Chen

引用次数: 0

Dependence of daytime thermospheric winds on IMF By as measured from south pole 从南极测得的白天热层风与 IMF By 的关系

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-10 DOI: 10.3389/fspas.2024.1426267

Ying Zou, Cheng Sheng, Mark Conde, Xueling Shi, William A. Bristow, Yen-Jung Joanne Wu

{"title":"Dependence of daytime thermospheric winds on IMF By as measured from south pole","authors":"Ying Zou, Cheng Sheng, Mark Conde, Xueling Shi, William A. Bristow, Yen-Jung Joanne Wu","doi":"10.3389/fspas.2024.1426267","DOIUrl":"https://doi.org/10.3389/fspas.2024.1426267","url":null,"abstract":"Winds in the nighttime upper thermosphere are often observed to mimic the ionospheric plasma convection at polar latitudes, and whether the same is true for the daytime winds remains unclear. The dayside sector is subject to large temperature gradient set up by solar irradiance and it also contains the cusp, which is a hotspot of Poynting flux and a region with the strongest soft particle precipitation. We examine daytime winds using a Scanning Doppler Imager (SDI) located at the South Pole, and investigate their distribution under steadily positive and negative IMF By conditions. The results show that daytime winds exhibit significant differences from the plasma convection. Under negative IMF By conditions, winds flow in the same direction as the plasma zonally, but have a meridional component that is strongest in the auroral zone. As a result, winds are more poleward-directed than the plasma convection within the auroral zone, and more westward-directed in the polar cap. Under positive IMF By conditions, winds can flow zonally against the plasma in certain regions. For instance, they flow westward in the polar cap despite the eastward plasma convection there, forming a large angle relative to the plasma convection. The results indicate that ion drag may not be the most dominant force for daytime winds. Although the importance of various forcing terms cannot be resolved with the utilized dataset, we speculate that the pressure gradient force in the presence of cusp heating serves as one important contributor.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"4 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141661815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Research on identification of nucleus-shaped anomaly regions in space electric field 空间电场中核状异常区的识别研究

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-10 DOI: 10.3389/fspas.2024.1431273

Xingsu Li, Zhong Li, Jianping Huang, Ying Han, Yumeng Huo, Junjie Song, Bo Hao

{"title":"Research on identification of nucleus-shaped anomaly regions in space electric field","authors":"Xingsu Li, Zhong Li, Jianping Huang, Ying Han, Yumeng Huo, Junjie Song, Bo Hao","doi":"10.3389/fspas.2024.1431273","DOIUrl":"https://doi.org/10.3389/fspas.2024.1431273","url":null,"abstract":"The presence of nucleus-shaped anomalous regions in the power spectrum image of the electric field VLF frequency band has been discovered in previous studies. To detect and analyze these nucleus-shaped abnormal areas and improve the recognition rate of nucleus-shaped abnormal areas, this paper proposes a new nucleus-shaped abnormal area detection model ODM_Unet (Omni-dimensional Dynamic Mobile U-net) based on U-net network. Firstly, the power spectrum image data used for training is created and labeled to form a dataset of nucleus-shaped anomalous regions; Secondly, the ODConv (Omni-dimensional Dynamic Convolution) module with embedded attention mechanism was introduced to improve the encoder, extracting nucleus-shaped anomaly region information from four dimensions and focusing on the features of different input data; An SDI (Semantics and Detail Infusion) module is introduced between the encoder and decoder to solve the problem of detail semantic loss in high-level images caused by the reduction of downsampling image size; In the decoder stage, the SCSE (Spatial and Channel Squeeze-and-Excitation) attention module is introduced to more finely adjust the feature maps output through the SDI module. The experimental results show that compared with the current popular semantic segmentation algorithms, the ODM_Unet model has the best detection performance in nucleus-shaped anomaly areas. Using this model to detect data from November 2021 to October 2022, it was found that the frequency of nucleus-shaped anomaly areas is mostly between 0 and 12.5KHz, with geographic spatial distribution ranging from 40° to 70° south and north latitudes, and magnetic latitude spatial distribution ranging from 58° to 80° south and north latitudes. This method has reference significance for detecting other types of spatial electromagnetic field disturbances.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"81 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141662783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A two-step strategy to identify episodic sources of gravitational waves and high-energy neutrinos in starburst galaxies 识别星爆星系中引力波和高能中微子偶发源的两步策略

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-05 DOI: 10.3389/fspas.2024.1394741

M. L. Allen, P. L. Biermann, L. Caramete, A. Chieffi, R. Chini, D. Frekers, L. Gergely, B. Harms, I. Jaroschewski, P. S. Joshi, P. P. Kronberg, E. Kun, A. Meli, E.-S. Seo, T. Stanev

{"title":"A two-step strategy to identify episodic sources of gravitational waves and high-energy neutrinos in starburst galaxies","authors":"M. L. Allen, P. L. Biermann, L. Caramete, A. Chieffi, R. Chini, D. Frekers, L. Gergely, B. Harms, I. Jaroschewski, P. S. Joshi, P. P. Kronberg, E. Kun, A. Meli, E.-S. Seo, T. Stanev","doi":"10.3389/fspas.2024.1394741","DOIUrl":"https://doi.org/10.3389/fspas.2024.1394741","url":null,"abstract":"Supermassive black hole (BH) mergers with spin-flips accelerate energetic particles through their relativistic precessing jets, producing high-energy neutrinos and finally gravitational waves (GWs). In star formation, massive stars form in pairs, triplets, and quadruplets, allowing second-generation mergers of the remnants with discrepant spin directions. The GW data support such a scenario. Earlier, we suggested that stellar mass BH mergers (visible in M82) with an associated spin-flip analogously allow the acceleration of energetic particles, with ensuing high-energy neutrinos and high-energy photons, and finally produce GWs. At cosmic distances, only the GWs and the neutrinos remain detectable. In this study, we generalize the argument to starburst and normal galaxies throughout their cosmic evolution and show that these galaxies may dominate over active galactic nuclei (AGN) in the flux of ultra-high-energy particles observed at Earth. All these sources contribute to the cosmic neutrino background, as well as the GW background (they detected lower frequencies). We outline a search strategy to find such episodic sources, which requires including both luminosity and flux density.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":" 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141673243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Radiation belt phase space density: calculation analysis and model dependence 辐射带相空间密度：计算分析和模型依赖性

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-04 DOI: 10.3389/fspas.2024.1423545

D. E. da Silva, S. Elkington, X. Li, M. K. Hudson, A. J. Boyd, A. Jaynes, M. Wiltberger

{"title":"Radiation belt phase space density: calculation analysis and model dependence","authors":"D. E. da Silva, S. Elkington, X. Li, M. K. Hudson, A. J. Boyd, A. Jaynes, M. Wiltberger","doi":"10.3389/fspas.2024.1423545","DOIUrl":"https://doi.org/10.3389/fspas.2024.1423545","url":null,"abstract":"The reprocessing of radiation belt electron flux measurements into phase space density (PSD) as a function of the adiabatic invariants is a widely-used method to address major questions regarding electron energization and loss in the outer radiation belt. In this reprocessing, flux measurements j (α, E) at local pitch angles α, energies E, and optionally magnetometer measurements B, are combined with a global magnetic field model to express the phase space density f (L*) in terms of the third invariant Φ ∝ 1/L* at fixed first and second invariants M and K. While the general framework of the calculation is agreed upon, implementation details vary amongst the literature, and the issue of magnetic field model dependence is rarely addressed. This work reviews the steps of the calculation with lists of commonly used implementation options. For the first time, analysis is presented to display the effect of doing the calculation with different implementation options and with different backing models (including both empirical and MHD-driven models). The results are summarized to inform evaluation of existing results and future efforts calculating and analyzing radiation belt electron phase space density. Three events are analyzed, and while differences are found, the primary structural interpretations of the phase space density analysis exhibit model independence.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":" 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141678848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Intermediate E-F layer dynamics study in the Brazilian low-latitude sector: observational data and simulations 巴西低纬度地区中间 E-F 层动力学研究：观测数据和模拟结果

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-03 DOI: 10.3389/fspas.2024.1403154

Marcio Muella, Ana P. M. Silva, Ângela M. dos Santos, V. Pillat, Laysa C. A. Resende, Vânia F. Andrioli, Paulo R. Fagundes

{"title":"Intermediate E-F layer dynamics study in the Brazilian low-latitude sector: observational data and simulations","authors":"Marcio Muella, Ana P. M. Silva, Ângela M. dos Santos, V. Pillat, Laysa C. A. Resende, Vânia F. Andrioli, Paulo R. Fagundes","doi":"10.3389/fspas.2024.1403154","DOIUrl":"https://doi.org/10.3389/fspas.2024.1403154","url":null,"abstract":"This study investigates the downward motion of Intermediate E-F Layers (ILs) in the Brazilian low latitude sector through observation and modeling. Ionosonde data from São José dos Campos (SJC) and Palmas (PAL) were analyzed to investigate the seasonal variation of the IL parameters, including the virtual height (h'IL) and the top frequency (ftIL). The ILs primarily originated from F layer detachment followed by downward motion, peaking before 11 LT and disappearing well before sunset. Daily height variability ranged between 130 and 190 km, with peak frequencies around 4–5 MHz. Using meteor radar data as input, the Ionospheric E-region Model (MIRE) simulated diurnal and semidiurnal tides to analyze neutral wind effects on ILs descent. Model simulations for SJC (October 2008) and PAL (April and June 2009) revealed distinct wind oscillations influencing IL dynamics at heights below 140 km. In SJC, meridional wind shears controlled IL descent, with possible zonal wind interactions weakening ILs. Conversely, in PAL during April 2009, both zonal and meridional winds contributed to IL formation and altitude descent. However, discrepancies between observed and modeled descent rates suggest the need for considering additional atmospheric wave interactions in future modeling studies. June 2009 over PAL presented unique IL behavior, exhibiting a lower observed decay rate and daily height oscillations potentially linked to local modulations. Meanwhile, MIRE indicated that meridional wind shearing predominantly controlled IL descent in the morning, with zonal wind becoming relevant post-midday. These findings enhance our understanding of IL dynamics and their atmospheric drivers.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"87 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141682762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Radio transients from compact objects across the mass spectrum in the era of multi-messenger astronomy 多信使天文学时代来自质量谱上紧凑天体的射电瞬变现象

Frontiers in Astronomy and Space Sciences Pub Date : 2024-07-01 DOI: 10.3389/fspas.2024.1401792

Alessandra Corsi, Avery Eddins, T. Lazio, Eric J. Murphy, R. Osten

引用次数: 0

On the overall properties of young neutron stars: an application to the Crab pulsar 关于年轻中子星的整体特性：对蟹脉冲星的应用

Frontiers in Astronomy and Space Sciences Pub Date : 2024-06-04 DOI: 10.3389/fspas.2024.1390597

Cristian G. Bernal, C. Frajuca, Henrique D. Hirsch, Beatriz Minari, N. Magalhaes, Lucas B. Selbach

引用次数: 0