Astronomy & Astrophysics最新文献

{"title":"UGC 10043 in depth: Dissecting the polar bulge and subtle low surface brightness features","authors":"S. K. H. Bahr, A. V. Mosenkov","doi":"10.1051/0004-6361/202554995","DOIUrl":"https://doi.org/10.1051/0004-6361/202554995","url":null,"abstract":"Galaxies with polar structures (of which polar-ring galaxies (PRGs) are a prominent subclass) contain components that are kinematically decoupled and highly inclined relative to the major axis of the host galaxy. Modern deep optical surveys provide a powerful means of detecting low surface brightness (LSB) features around galaxies, which offers critical insights into the formation and evolution of galaxies with polar structures. UGC 10043 is an edge-on galaxy that is notable for its prominent bulge, which extends orthogonally to the disk plane. In addition, the galaxy displays a well-defined integral-shaped disk warp and multiple dust features crossing the bulge along the minor galaxy axis. We present new deep optical photometry of UGC 10043 down to <i>μ<i/><sub><i>g<i/><sub/> = 29.5 mag arcsec<sup>−2<sup/> and perform a detailed analysis of its LSB and polar structures. The observations reveal a stellar stream aligned along the polar axis, alongside other signatures of tidal interaction, including a flat, tilted LSB envelope that extends toward the neighboring galaxy MCG +04-37-035, with which UGC 10043 is connected by an HI bridge. Our results suggest that the polar component of UGC 10043 comprises an older, triaxial polar bulge and a younger, forming polar structure that likely originates from the ongoing disruption of a dwarf satellite galaxy. It also simultaneously participates in active interaction with MCG +04-37-035.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"12 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"The incidence of magnetic cataclysmic variables can be explained by the late appearance of white dwarf magnetic fields","authors":"Matthias R. Schreiber, Diogo Belloni","doi":"10.1051/0004-6361/202554828","DOIUrl":"https://doi.org/10.1051/0004-6361/202554828","url":null,"abstract":"<i>Context.<i/> Assuming that white dwarf (WD) magnetic fields are generated by a crystallization- and rotation-driven dynamo, the impact of the late appearance of WD magnetic fields in cataclysmic variables (CVs) has been shown to potentially solve several long-standing problems of CV evolution. However, recent theoretical works show that the dynamo idea might not be viable and that the late appearance of WD magnetic fields might be an age effect rather than related to the cooling of the core of the WD.<i>Aims.<i/> We investigated the impact of the late appearance of WD magnetic fields on CV evolution assuming that the fields appear at fixed WD ages.<i>Methods.<i/> We performed CV population synthesis with the BSE code to determine the fractions of CVs that become magnetic at different evolutionary stages. These simulations were complemented with MESA tracks that take into account the transfer of spin angular momentum to the orbit which can cause a detached phase.<i>Results.<i/> We find that the observed fraction of magnetic CVs as a function of orbital period is well reproduced by our simulations, and that in many CVs the WD should become magnetic close to the period minimum. The detached phase generated by the transfer of spin angular momentum is longest for period bouncers.<i>Conclusions.<i/> Interpreting the late appearance of strong WD magnetic fields as a simple age effect naturally explains the relative numbers of magnetic CVs in observed samples. As many period bouncers might detach for several gigayears, the late appearance of WD magnetic fields at a fixed age and independent of the core temperature of the WD can significantly reduce the predicted number of accreting period bouncers.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"33 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"From small dust to micron-sized aggregates: The influence of structure and composition on the dust optical properties","authors":"M.-A. Carpine, N. Ysard, A. Maury, A. Jones","doi":"10.1051/0004-6361/202554575","DOIUrl":"https://doi.org/10.1051/0004-6361/202554575","url":null,"abstract":"<i>Context.<i/> Models of astrophysical dust are key to understanding several physical processes, from the role of dust grains as cooling agents in the interstellar medium (ISM) to their evolution in dense circumstellar discs, explaining the occurrence of planetary systems around many stars. Currently, most models aim to provide optical properties for dust grains in the diffuse ISM, and many do not account properly for complexity in terms of composition and structure when dust is expected to evolve in dense astrophysical environments.<i>Aims.<i/> Our purpose is to investigate, with a pilot sample of micron-size dust grains, the influence of hypotheses made about the dust structure, porosity, and composition when computing the optical properties of grown dust grains. We aim to produce a groundwork for building comprehensive yet realistic optical properties that accurately represent dust grains as they are expected to evolve in the dense clouds, cores, and discs. We are especially interested in exploring these effects on the resulting optical properties in the infrared and millimetre domains, where observations of these objects are widely used to constrain the dust properties.<i>Methods.<i/> Starting from the small dust grains developed in the THEMIS 2.0 model, we used the discrete dipole approximation to compute the optical properties of 1 μm grains, varying the hypotheses made about their composition and structure. We looked at the dust scattering, emission, and extinction to isolate potential simplifications and unavoidable differences between grain structures.<i>Results.<i/> We note significant differences in the optical properties depending on the dust structure and composition. Both the dust structure and porosity influence the dust properties in infrared and millimetre ranges, demonstrating that dust aggregates cannot be correctly approximated by compact or porous spheres. In particular, we show that the dust emissivity index in the millimetre can vary with fixed grain size.<i>Conclusions.<i/> Our work sheds light on the importance of taking the dust structure and porosity into account when interpreting observations in astrophysical environments where dust grains may have evolved significantly. For example, measuring the dust sizes using the emissivity index from millimetre observations of the dust thermal emission is a good but degenerate tool, as we observe differences of up to 25% in the dust emissivity index with compact or aggregate grains, varying in composition and structure. Efforts in carrying out physical models of grain growth, for instance, are required to establish realistic constraints on the structure of grown dust grains, and will be used in the future to build realistic dust models for the dense ISM.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"592 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Discovery of propenethial (CH2CHCHS) in TMC-1","authors":"C. Cabezas, K. Vávra, G. Molpeceres, L. Kolesniková, M. Agúndez, G. Vylitová, N. Marcelino, L. Hrubčík, R. Fuentetaja, T. Uhlíková, B. Tercero, J. Koucký, G. Esplugues, P. Kania, P. de Vicente, Š. Urban, J. Cernicharo","doi":"10.1051/0004-6361/202554670","DOIUrl":"https://doi.org/10.1051/0004-6361/202554670","url":null,"abstract":"We present the detection of propenethial (CH<sub>2<sub/>CHCHS), the sulphur analogue of interstellar acrolein (CH<sub>2<sub/>CHCHO), towards TMC-1. The detection of this new sulphur molecule in TMC-1 is based on the data derived from rotational spectroscopy laboratory experiments, including new data in the millimetre wave domain, which are also presented in this work. Propenethial was observed in the cold dark cloud TMC-1 using data from the ongoing QUIJOTE line survey, which is being carried out with the Yebes 40m telescope. A total of nine rotational transitions with <i>J<i/> = 6 up to 9 and <i>K<i/><sub><i>a<i/><sub/> = 0 and 1 were detected in the 31.0–50.4 GHz range. We derive a total column density for propenethial of (4.4 ± 0.4) × 10<sup>10<sup/> cm<sup>−2<sup/>, which is 2, 6.8, and 27 times smaller than those for CH<sub>3<sub/>CHS, HCCHS, and NCCHS, which are the other thioaldehyde derivatives detected in TMC-1. The abundance ratio found in TMC-1 between the aldehyde counterpart, acrolein, and propenethial is 4.7, which is also different from those found for other pairs of aldehydes-thioaldehydes in this source. Our investigation of possible chemical formation pathways suggests that CH<sub>2<sub/>CHCHS likely results from a combination of gas- and surface-phase reactions.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"65 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Ionisation balance and equation of state of hot, dense carbon plasmas at pressures up to a few 100 Gbar","authors":"Jiaolong Zeng, Yihua Huang, Aihua Deng, Cheng Gao, Yong Hou, Jianmin Yuan","doi":"10.1051/0004-6361/202554609","DOIUrl":"https://doi.org/10.1051/0004-6361/202554609","url":null,"abstract":"Accurately determining the ionisation balance and the equation of state (EOS) of dense plasmas is crucial for investigating the structure, evolution, and interior of stars, as well as other high-density astrophysical objects. However, it is still challenging for current experiments and theories to achieve this objective for dense plasmas at pressures up to a few 100 Gbar. Here, we modify the chemical picture of the Saha equation of plasmas and extend it into a regime up to a density of a few hundred g cm<sup>−3<sup/> based on the minimisation of the free energy of the system. The non-ideal characteristics (NIC) of the free energy, particularly the part contributed by Coulomb interactions between electrons and ions, as well as among the electrons and ions themselves, are properly accounted for by employing a local-density, temperature-dependent ion-sphere model. In such a way, the NIC effects on the ionisation potential depression, the internal partition functions of the ions, and the partition functions of the free electrons are properly considered in the modified Saha equation. Hence, the ionisation balance and EOS are self-consistently determined in this theoretical formalism. We demonstrate the capability of this modified Saha equation for solving hot, dense carbon plasmas, and find that the accurate prediction of the critical density above which the K-shell electrons become delocalised by pressure is crucial for accurately obtaining the charge state distribution and the EOS. Comparisons are made for the average degree of ionisation and EOS of carbon plasmas with available data reported in the literature. Our predicted EOS gives a result in reasonable agreement with other theoretical results below the critical density of pressure-driven K-shell delocalisation. Nevertheless, above this critical density, our prediction is systematically higher by ~25% compared to most other theories. At mass densities around 5 g cm<sup>−3<sup/>, our predicted opacity of dense hydrocarbon plasmas agrees with a recent experiment studying the EOS along the principal shock Hugoniot, which can be considered a validation of our theory at this density regime.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"13 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"The p-Laplacian as a framework for generalizing Newtonian gravity and Milgromian gravitation","authors":"D. Scherer, J. Pflamm-Altenburg, P. Kroupa, E. Gjergo","doi":"10.1051/0004-6361/202554793","DOIUrl":"https://doi.org/10.1051/0004-6361/202554793","url":null,"abstract":"<i>Context.<i/> The radial acceleration relation (RAR) follows from Milgromian gravitation (MoND) and velocity dispersion data of many dwarf spheroidal galaxies (dSphs) and galaxy clusters have been reported to be in tension with it.<i>Aims.<i/> We consider the generalized Poisson equation (GPE), expressed in terms of the p-Laplacian, which has been applied in electrodynamics, and investigate whether it can address these tensions.<i>Methods.<i/> From the GPE we derive a generalized RAR characterized by the <i>p<i/> parameter from the p-Laplacian and a velocity dispersion formula for a Plummer model. We apply these models to Milky Way and Andromeda dSphs and HIFLUGS galaxy clusters and derive a <i>p<i/> parameter for each dSph and galaxy cluster. We explore a relation of <i>p<i/> to the mass density of the bound system, and alternatively a relation of <i>p<i/> to the external field predicted from Newtonian gravity<i>Results.<i/> This ansatz allows the deviations of dSphs and galaxy clusters from the RAR without the need of introducing dark matter. Data points deviate from the Milgromian case, <i>p<i/> = 3, with up to 5<i>σ<i/>-confidence. Also, we find the model predicts velocity dispersions, each of which lies in the 1<i>σ<i/>-range of their corresponding data point allowing the velocity dispersion to be predicted for early-type dwarf satellite galaxies from their baryonic density. The functional relation between the mass density of the bound system and <i>p<i/> suggests <i>p<i/> to increase with decreasing density. We find for the critical cosmological density <i>p<i/>(<i>ρ<i/><sub>crit<sub/>) = 12.27±0.39. This implies significantly different behaviour of gravitation on cosmological scales. Alternatively, the functional relation between <i>p<i/> and the external Newtonian gravitational field suggests <i>p<i/> to decrease with increasing field strength.<i>Conclusions.<i/> The GPE fits the RAR data of dSphs and galaxy clusters, reproduces the velocity dispersions of the dSphs, gives a prediction for the velocity dispersion of galaxy clusters from their baryonic density and may explain the non-linear behaviour of galaxies in regions beyond the Newtonian regime.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"230 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"New constraints on the values of the fundamental constants at a look-back time of 7.3 Gyr","authors":"Renzhi Su, Stephen J. Curran, Françoise Combes, Neeraj Gupta, Sebastien Muller, Di Li, Minfeng Gu","doi":"10.1051/0004-6361/202453407","DOIUrl":"https://doi.org/10.1051/0004-6361/202453407","url":null,"abstract":"The study of redshifted spectral lines can provide a measure of the fundamental constants over large look-back times. Current grand unified theories predict an evolution in these constants and astronomical observations offer the only experimental measure of the values of the constants over large timescales. Of particular interest are the dimensionless constants: the fine structure constant (<i>α<i/>), the proton-electron mass ratio (<i>μ<i/>), and the proton g-factor (<i>g<i/><sub><i>p<i/><sub/>), since these do not require a “standard meterstick”. Here we present a re-analysis of the 18 cm hydroxyl (OH) lines at <i>z<i/> = 0.89, which were recently detected with the MeerKAT telescope, toward the radio source PKS 1830-211. Utilizing the previous constraint of Δ<i>μ<i/>/<i>μ<i/>=(−1.8±1.2)×10<sup>−7<sup/>, we obtain , Δ<i>α<i/>/<i>α<i/>≲2.3×10<sup>−3<sup/>, and Δ<i>g<i/><sub><i>p<i/><sub/>/<i>g<i/><sub><i>p<i/><sub/>≲7.9×10<sup>−3<sup/>. These new constraints are consistent with no evolution over a look-back time of 7.3 Gyr and provide another valuable data point in the putative evolution of the constants.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"70 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Particle acceleration and multi-messenger radiation from ultra-luminous X-ray sources","authors":"Enrico Peretti, Maria Petropoulou, Georgios Vasilopoulos, Stefano Gabici","doi":"10.1051/0004-6361/202452987","DOIUrl":"https://doi.org/10.1051/0004-6361/202452987","url":null,"abstract":"Super-Eddington accretion onto stellar-mass compact objects powers fast outflows in ultra-luminous X-ray sources (ULXs). Such outflows, which can reach mildly relativistic velocities, are often observed forming bubble structures. Wind bubbles are expected to develop strong wind termination shocks, which are sites of great interest for diffusive shock acceleration. We developed a model of diffusive shock acceleration in the wind bubbles powered by ULXs. We find that the maximum energy in these objects can easily reach the PeV range, promoting winds from ULXs as a new class of PeVatrons. We specialized our model in the context of the Galactic source SS 433 and show that high-energy protons in the bubble might explain the highest energy photons (>100 TeV) and their morphology recently observed by LHAASO. In this paper, we discuss the detectability of such a source in neutrinos, and we analyze the possible radio counterpart of ULXs focusing on the case of W50, the nebula surrounding SS 433. Finally, we discuss the possible contribution of Galactic ULXs to the cosmic-ray flux at the knee, concluding that their role could be significant only if one of these sources, currently undetected, were sufficiently close.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"25 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Imaging and spectropolarimetric observations of a band-split type II solar radio burst with LOFAR","authors":"S. Normo, D. E. Morosan, P. Zhang, P. Zucca, R. Vainio","doi":"10.1051/0004-6361/202553702","DOIUrl":"https://doi.org/10.1051/0004-6361/202553702","url":null,"abstract":"<i>Context.<i/> Type II solar radio bursts are generated by electrons accelerated by coronal shock waves. They appear in dynamic spectra as lanes drifting from higher to lower frequencies at the plasma frequency and its harmonic. These lanes can often be split into two or more sub-bands that have similar drift rates. This phenomenon is called band-splitting, and its physical origins are still under debate.<i>Aims.<i/> Our aim is to investigate the origin of band-splitting using novel imaging and spectropolarimetric observations of a type II solar radio burst from the Low Frequency Array (LOFAR).<i>Methods.<i/> We used LOFAR imaging at multiple frequencies and time steps to track the locations of the radio sources corresponding to the two components of the band-split emission lane. In addition, we estimated the degree of circular polarisation (dcp) for both components using LOFAR's full Stokes dynamic spectra.<i>Results.<i/> From the imaging of the type II burst, we found two close but clearly separated emission regions clustered over several frequencies spanning each split band. One emission region corresponds to the lower frequency band and the other to the higher frequency band of the split lane. Using the full Stokes dynamic spectra, we also found the dcp to be very similar for both bands.<i>Conclusions.<i/> The two distinct emission regions suggest that the split bands originate from two separate regions at the shock. The similar values of dcp for both sub-bands correspond to similar values of magnetic field strength in the two regions and indicate little to no change in the emission region plasma. Thus, our findings are in contradiction with previous theories, which have suggested that split bands originate in the same region but upstream and downstream of the shock. Instead, our results suggest that both bands originate in two separate upstream regions since we find a clear separation in locations and no magnetic compression.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"12 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"The influence of external solar-wind drivers on the physical characteristics of the Martian bow shock","authors":"Shibang Li, Haoyu Lu, Christian Mazelle, Jinbin Cao, Xiaoshu Wu, Yasong Ge, Nihan Chen, Yihui Song, Jianxuan Wang, Yuchen Cao, Jianing Zhao","doi":"10.1051/0004-6361/202554525","DOIUrl":"https://doi.org/10.1051/0004-6361/202554525","url":null,"abstract":"The Martian bow shock represents the main interface between the upstream interplanetary space and the downstream planetary obstacle, where the solar-wind plasma and the frozen-in interplanetary magnetic field (IMF) begin to be perturbed. However, the physical characteristics of the Martian bow shock layer and the influence of the external solar wind drivers on them remain unclear. By employing a three-dimensional Hall magneto-hydrodynamic (MHD) model, this study aims to reveal the physical characteristics of the Martian bow-shock layer extracted from the maximum radially inward gradient of the solar-wind velocity (<i><b>V<b/><sub>S W<sub/><i/>), including the magnetic field, current density, electric fields, and the energy transfer between the fields and solar wind protons, as well as the influence of the <i><b>V<b/><sub>S W<sub/><i/> and the IMF on these features. Simulation results indicate that the IMF has initiated the processes of piling-up, draping, bending, and slipping at the Martian bow shock, inducing an associate current to flow from the +<i>Z<sub>MS E<sub/><i/> pole to the −<i>Z<sub>MS E<sub/><i/> pole along the bow-shock layer, with the strongest being located at the subsolar position. Furthermore, the total electric field at the Martian bow shock is constituted by the motional electric field (<i><b>E<b/><sub>M<sub/><i/>) with the +<i>Z<sub>MS E<sub/><i/> direction around the ±<i>Z<sub>MS E<sub/><i/> flanks and the outward ambipolar (<i><b>E<b/><sub>A<sub/><i/>) and Hall (<i><b>E<b/><sub>H<sub/><i/>) electric fields around the lower solar zenith angles; through these, the solar wind transfers its kinetic energy to the electromagnetic fields. A higher <i><b>V<b/><sub>S W<sub/><i/> gives rise to an enhanced magnetic field, current density, and electric fields at the Martian bow shock, thereby leading to an increase in the corresponding energy-transfer rates. A greater magnitude of the IMF cross-flow component tends to result in an intensified magnetic field, current densities, <i><b>E<b/><sub>M<sub/><i/>, and <i><b>E<b/><sub>H<sub/><i/>; while it causes a decreased <i><b>E<b/><sub>A<sub/><i/> and associated energy-transfer rate at the bow shock layer. If the Parker spiral angle of the IMF is not restricted to 90°, a portion of the quasi-parallel bow-shock layer will be formed, within which the magnitudes of the magnetic field, current density, <i><b>E<b/><sub>H<sub/><i/>, and the corresponding energy-transfer rate through <i><b>E<b/><sub>H<sub/><i/> are all lower than those of the quasi-perpendicular bow-shock layer. The results of this study provide valuable insights into the physical properties at the bow-shock layer that emerge during the Mars-solar-wind interactions.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"37 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}