Astrophysics and Space Science最新文献

{"title":"Cometary observations in light-polluted environments: a case study of interstellar comet 2I/Borisov","authors":"Josep M. Trigo-Rodríguez,&nbsp;Damya Souami,&nbsp;Maria Gritsevich,&nbsp;Marcin Wesołowski,&nbsp;Gennady Borisov","doi":"10.1007/s10509-025-04424-9","DOIUrl":"10.1007/s10509-025-04424-9","url":null,"abstract":"<div><p>Comets and asteroids have long captured human curiosity, and until recently, all documented examples belonged to our Solar System. That changed with the discovery of the first known interstellar object, 1I/2017 U1 (‘Oumuamua), in 2017. Two years later, on August 30, 2019, Gennady Borisov discovered a second interstellar object, 2019 Q4, which was officially designated 2I/Borisov. From its initial images, the object’s diffuse appearance hinted at its cometary nature. To better understand the photometric evolution of comet 2I/Borisov as it traveled through the inner Solar System, we compiled observations using medium-sized telescopes. This data is crucial for gaining insights into its size and composition, as well as how such objects, after millions of years in interstellar space, behave when exposed to the Sun’s radiation. Given that 2I/Borisov is the first interstellar comet ever observed, constraining its behavior is of great scientific interest. In this paper, we present photometric data gathered from observatories in Crimea and Catalonia, highlighting the importance of systematic photometric studies of interstellar objects using meter-class telescopes. Our observations showed a steady increase in the comet’s brightness as it approached perihelion, likely due to the slow sublimation of ices. Over the five-month pre-perihelion observation period, we did not detect any significant changes in magnitude. The analysis of observations reveals a steady increase in comet 2I/Borisov brightness as it approached perihelion, likely due to the sublimation of ices, with no observable outbursts during the five-month pre-perihelion period. Additionally, we discuss the challenges in ground-based observation of comets posed by light pollution today, particularly in urban areas, where visual observations are severely limited. Using sample surface brightness measurements, we demonstrate the impact of light pollution and outline the importance of systematic photometric studies for interstellar objects.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10509-025-04424-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the role of space weather indices in the prediction of total electron content at different latitudes during geomagnetic storms","authors":"Fei Xu,&nbsp;Dongjie Yue,&nbsp;Changzhi Zhai,&nbsp;Xin Gao,&nbsp;Yutian Chen","doi":"10.1007/s10509-025-04422-x","DOIUrl":"10.1007/s10509-025-04422-x","url":null,"abstract":"<div><p>The Total Electron Content (TEC) is an important parameter that describes the morphology and structure of the ionosphere. Deep learning is an important and effective tool for forecasting TEC, but the role of different solar activity indices and geomagnetic indices in TEC prediction remains unclear. The Long Short-Term Memory (LSTM) network has special structure design and good generalization ability, which is capable of learning the features of long-term sequence data and has been widely applied in the research of ionosphere prediction. Therefore, in this study, the LSTM network is used to achieve short-term forecasting of low, middle, and high latitudes TEC during geomagnetic storms that occurred in 2016. At the same time, the effects of four different index combinations, F10.7, Kp, Dst, and AE indices, on the prediction results at different latitudes were analyzed. The results show that the appropriate combination of index inputs effectively improves the prediction performance of the model. At low latitudes, the model incorporating Kp, Dst and F10.7 indices performed best, with a 51.3% average decrease in RMSE compared to the model without any additional indices. The best model is one that uses Kp and F10.7 indices at middle latitudes, compared to model without any indices, its average RMSE decreased by 57.0%. At high latitudes, the model using Kp, Dst, and AE indices performed best, with a 43.2% average decrease in RMSE compared to the model without any indices. However, more indices do not necessarily improve prediction accuracy.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143726611","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}

{"title":"Karmarkar Bardeen anisotropic model for compact stars in (mathcal{F}(mathcal{R},mathcal{T})) gravity","authors":"Furqan Nazeer,&nbsp;Tooba Feroze","doi":"10.1007/s10509-025-04423-w","DOIUrl":"10.1007/s10509-025-04423-w","url":null,"abstract":"<div><p>This paper aims to obtain a new Class-I solution of the field equations in <span>(mathcal{F}(mathcal{R},mathcal{T}))</span> gravitational theory for the charged anisotropic spherically symmetric distribution. For this purpose, a new spacetime metric function is put forth and employed in the Karmarkar condition. The uniform charge distribution in the stellar interior is considered and the Class-I spacetime is seamlessly matched to Bardeen geometry at the boundary. Moreover, a detailed analysis is conducted to study the physical attributes of the stars Vela <i>X-1</i>, SMC <i>X-4</i>, SAX J<i>1808.4-3658</i>, Her <i>X-1</i> and Cen <i>X-3</i>, all obeying the essential conditions for a solution to be physically acceptable. A comprehensive review of stability criteria involving the energy conditions and adiabatic is provided complying with the requirement. In addition, an in-depth exploration of the Tolman-Oppenheimer-Volkoff’s (TOV) equation leads to the stellar configuration being in an equilibrium state.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143726610","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}

{"title":"Design and analysis of abort orbits for manned missions to the Earth-Moon libration points","authors":"Yuebo Wang,&nbsp;Yamin Wang,&nbsp;Huichang Yu,&nbsp;Yonghe Zhang","doi":"10.1007/s10509-025-04421-y","DOIUrl":"10.1007/s10509-025-04421-y","url":null,"abstract":"<div><p>A libration-point orbit (LPO) offers low-cost access to space and may be the destination of future manned missions. Usually, a lunar flyby is required for short-term LPO missions, thus the transfer trajectory from the Earth to LPO is composed of an Earth–Moon two-body leg and a Moon–LPO three-body leg. The abort orbit associated with the Earth–Moon two-body leg has been thoroughly studied. In this paper, the abort orbit of the Moon–LPO three-body leg is designed and analyzed. Along the Moon–LPO three-body leg, the abort orbits of direct, lunar-flyby, and low-energy return are designed and discussed separately. For the direct return, the abort orbits are obtained based on an initial Kepler solution with reentry constraint. For the lunar-flyby return, the abort orbits are designed by pseudostate theory. For the low-energy return, the abort orbits are further optimized by introducing nontransit/transit orbits and lunar flyby. In the Earth–Lissajous transfer scenario, three types of abort orbits for the Moon–LPO three-body leg are numerically designed. For the direct or lunar-flyby return case, the total impulse of abort orbits is greater than 0.9 km/s. This is a significant burden for manned mission planning. For the low-energy return, the minimum total impulses are 0.302 km/s and save 20–60% total impulse at the cost of a limited increase in flight time. This abort orbit employs a nontransit/transit orbit to return to the vicinity of the Moon and quickly return to Earth after applying a second maneuver at perilune. Finally, return windows and trajectory types of abort orbits are classified based on a reference trajectory.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716890","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}

{"title":"Projective quadrics and orbital elements","authors":"Alberto J. Marín Fdez. de Capel,&nbsp;Miguel Ángel Sánchez Granero","doi":"10.1007/s10509-025-04420-z","DOIUrl":"10.1007/s10509-025-04420-z","url":null,"abstract":"<div><p>Due to the fact that Keplerian orbits are conic sections, projective geometry gives a description of orbits based on projective hyperquadric properties. Using matrix algebra to describe hyperquadrics allows the construction of a new set of orbital elements using the eigenvalues and eigenvectors of the improper hyperquadric matrix and the construction of reference systems associated with the orbit. It is possible to work directly with the orbit in Cartesian coordinates in the three-dimensional space as a 4x4 matrix, constructing the quadric associated with the orbital conic.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10509-025-04420-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advancing European high-contrast imaging R&D towards the Habitable Worlds Observatory","authors":"Iva Laginja,&nbsp;Óscar Carrión-González,&nbsp;Romain Laugier,&nbsp;Elisabeth Matthews,&nbsp;Lucie Leboulleux,&nbsp;Axel Potier,&nbsp;Alexis Lau,&nbsp;Olivier Absil,&nbsp;Pierre Baudoz,&nbsp;Beth Biller,&nbsp;Anthony Boccaletti,&nbsp;Wolfgang Brandner,&nbsp;Alexis Carlotti,&nbsp;Gaël Chauvin,&nbsp;Élodie Choquet,&nbsp;David Doelman,&nbsp;Kjetil Dohlen,&nbsp;Marc Ferrari,&nbsp;Sasha Hinkley,&nbsp;Elsa Huby,&nbsp;Mikael Karlsson,&nbsp;Oliver Krause,&nbsp;Jonas Kühn,&nbsp;Jean-Michel Le Duigou,&nbsp;Johan Mazoyer,&nbsp;Dino Mesa,&nbsp;Michiel Min,&nbsp;David Mouillet,&nbsp;Laurent M. Mugnier,&nbsp;Gilles Orban de Xivry,&nbsp;Frans Snik,&nbsp;Daniele Vassallo,&nbsp;Arthur Vigan,&nbsp;Pieter de Visser","doi":"10.1007/s10509-025-04417-8","DOIUrl":"10.1007/s10509-025-04417-8","url":null,"abstract":"<div><p>The Habitable Worlds Observatory (HWO) will enable a transformative leap in the direct imaging and characterization of Earth-like exoplanets. For this, NASA is focusing on early investment in technology development prior to mission definition and actively seeking international partnerships earlier than for previous missions. The “R&amp;D for Space-Based HCI in Europe” workshop, held in March 2024 at Paris Observatory, convened leading experts in high-contrast imaging (HCI) to discuss European expertise and explore potential strategies for European contributions to HWO. This paper synthesizes the discussions and outcomes of the workshop, highlighting Europe’s critical contributions to past and current HCI efforts, the synergies between ground- and space-based technologies, and the importance of laboratory testbeds and collaborative funding mechanisms. Key conclusions include the need for Europe to invest in technology development for areas such as deformable mirrors and advanced detectors, and establish or enhance laboratory facilities for system-level testing. Putting emphasis on the urgency of aligning with the timeline of HWO, the participants called on an open affirmation by the European Space Agency (ESA) that a European contribution to HWO is clearly anticipated, to signal national agencies and unlock funding opportunities at the national level. Based on the expertise demonstrated through R&amp;D, Europe is poised to play a pivotal role in advancing global HCI capabilities, contributing to the characterization of temperate exoplanets and fostering innovation across domains.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10509-025-04417-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143668169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pre-existing turbulence and its influence on particle acceleration at astrophysical shocks","authors":"Ji-Hoon Ha","doi":"10.1007/s10509-025-04419-6","DOIUrl":"10.1007/s10509-025-04419-6","url":null,"abstract":"<div><p>Understanding the physics of particle acceleration at shocks is a long-standing problem in space science and astrophysics. Because particles are energized across the shock upstream and downstream through Diffusive Shock Acceleration (DSA), the characteristics of upstream and downstream plasma waves involved in wave-particle interactions have been extensively examined. While many studies have focused on self-excited plasma instabilities due to shock-reflected and accelerated particles, the roles of pre-existing turbulence in astrophysical environments could be substantial for wave-particle interactions near the shock. This work specifically investigates the effects of pre-existing turbulence in the shock upstream on DSA efficiency. The normalization and slope of turbulent spectra are used as parameters to determine the characteristics of pre-existing turbulence. Since pre-existing turbulence can confine particles upstream and regulate their efficient acceleration through DSA across the shock, the DSA efficiency decreases as the strength of turbulence increases. Furthermore, the effects of pre-existing turbulence become less significant in plasma systems with higher plasma beta, as diffusion mediated by both self-excited waves and pre-existing turbulence becomes less efficient as plasma beta increases. The modeling presented in this work could be generally applicable to shocks propagating through turbulent regions.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655294","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}

{"title":"A study on the evolutionary period changes of short-period type II cepheids","authors":"Alemiye Mamo Yacob,&nbsp;Leonid N. Berdinkov,&nbsp;Elena N. Pastukhova","doi":"10.1007/s10509-025-04418-7","DOIUrl":"10.1007/s10509-025-04418-7","url":null,"abstract":"<div><p>We investigate the period changes of 13 short-period Type II Cepheids using the O-C method over a century-long data baseline. The O-C diagrams for these stars exhibit a parabolic trend, indicating both increasing and decreasing period changes over time. These observed period changes are consistent with recent theoretical models based on horizontal branch evolutionary models for short-period BL Her stars. The pulsation stability test proposed by Lombard and Koen confirms that the period changes are significant, indicating evolutionary shifts. We identify seven BL Her stars with decreasing periods, expanding the existing sample size of short-period Type II Cepheids. This contributes to a deeper understanding of stellar evolution and the processes governing low-mass stars.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655295","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}

{"title":"Equilibria and stability in the restricted ((n+1))-body problem with logarithm potential","authors":"A.-M. Muscaş,&nbsp;Daniel Paşca,&nbsp;Cristina Stoica","doi":"10.1007/s10509-025-04415-w","DOIUrl":"10.1007/s10509-025-04415-w","url":null,"abstract":"<div><p>We study the existence and stability of equilibria in the regular n-gon restricted <span>((n+1))</span>-body problem with logarithm potential. We determine two classes of equilibria: “infinitesimal-Eulerian” situated along lines joining the n-gon centre with a vertex (i.e. along the radii), and “infinitesimal-Lagrangian” situated on the perpendicular bisectors of the n-gon sides. The infinitesimal-Eulerian equilibria are all positioned outside the primaries n-gon and are unstable. The infinitesimal-Lagrangian equilibria appear in two families: an unstable family in the interior of the primaries’ polygon, and a linearly stable family in the exterior. We also prove the existence of an equilibrium at the centre of the polygon that is unstable.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143645636","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}

{"title":"On the formation of cometary nuclei in a primordial gas cloud","authors":"Mayer Humi","doi":"10.1007/s10509-025-04416-9","DOIUrl":"10.1007/s10509-025-04416-9","url":null,"abstract":"<div><p>One of the current theories about the formation of a planetary system conjectures that traveling waves within a primordial interstellar gas cloud might have led, eventually, to the formation of the planets. As an initial step in this process embedded solid particles within a traveling wave may commence self-gravitational accumulation at the wave crests, where the pressure and density are highest, so possibly leading to the formation of cometary nuclei. To test the validity of this conjecture we present in this paper a prototype model for the evolution of systems of self gravitating particles. This model is applied to linear and circular traveling waves and ensembles of particles in a disk. We show that under proper conditions these systems might undergo a bifurcation or “self organization” which leads to the formation of cometary nuclei.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":"370 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143638205","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}