Pub Date : 2026-02-09DOI: 10.1051/0004-6361/202556235
M. De Leo, M. Zoccali, J. Olivares-Carvajal, B. Acosta-Tripailao, F. Gran, R. Contreras-Ramos
Context. In hierarchical structure formation, the content of a galaxy is determined both by its in-situ processes and by material added via accretions. Globular clusters, in particular, represent a window into the study of the different merger events that a galaxy has undergone. Establishing the correct classification of in-situ and accreted tracers, and distinguishing the various progenitors that contributed to the accreted population are important tools to deepen our understanding of galactic formation and evolution.Aims. This study aims to refine our knowledge of the Milky Way’s assembly history by examining the dynamics of its globular cluster population and establishing an updated classification among in-situ objects and the different merger events identified.Methods. We used a custom-built orbit integrator to derive precise orbital parameters, integrals of motions and adiabatic invariants for the globular cluster sample studied. By properly accounting for the rotating bar, which transforms the underlying model into a time-varying potential, we performed a complete dynamical characterisation of the globular clusters.Results. We present a new catalogue of clear associations between globular clusters and structures (both in-situ and accreted) in the Milky Way, along with a full table of derived parameters. Using all available dynamical information, we attributed previously unassociated or misclassified globular clusters to different progenitors, including those responsible for the Aleph, Antaeus, Cetus, Elqui, and Typhon merger events.Conclusions. Using a custom-built orbit integrator and properly accounting for the time-varying nature of the Milky Way potential, we demonstrate the depth of information that can be extracted from a purely dynamical analysis of the Galaxy’s globular clusters. Merging our dynamical analysis with complementary chronochemical studies, will allow us to uncover the remaining secrets of the accretion history of the Milky Way.
{"title":"Globular clusters in ORBIT: Complete dynamical characterisation of the Milky Way globular cluster population through updated orbital reconstruction","authors":"M. De Leo, M. Zoccali, J. Olivares-Carvajal, B. Acosta-Tripailao, F. Gran, R. Contreras-Ramos","doi":"10.1051/0004-6361/202556235","DOIUrl":"https://doi.org/10.1051/0004-6361/202556235","url":null,"abstract":"<i>Context<i/>. In hierarchical structure formation, the content of a galaxy is determined both by its in-situ processes and by material added via accretions. Globular clusters, in particular, represent a window into the study of the different merger events that a galaxy has undergone. Establishing the correct classification of in-situ and accreted tracers, and distinguishing the various progenitors that contributed to the accreted population are important tools to deepen our understanding of galactic formation and evolution.<i>Aims<i/>. This study aims to refine our knowledge of the Milky Way’s assembly history by examining the dynamics of its globular cluster population and establishing an updated classification among in-situ objects and the different merger events identified.<i>Methods<i/>. We used a custom-built orbit integrator to derive precise orbital parameters, integrals of motions and adiabatic invariants for the globular cluster sample studied. By properly accounting for the rotating bar, which transforms the underlying model into a time-varying potential, we performed a complete dynamical characterisation of the globular clusters.<i>Results<i/>. We present a new catalogue of clear associations between globular clusters and structures (both in-situ and accreted) in the Milky Way, along with a full table of derived parameters. Using all available dynamical information, we attributed previously unassociated or misclassified globular clusters to different progenitors, including those responsible for the Aleph, Antaeus, Cetus, Elqui, and Typhon merger events.<i>Conclusions<i/>. Using a custom-built orbit integrator and properly accounting for the time-varying nature of the Milky Way potential, we demonstrate the depth of information that can be extracted from a purely dynamical analysis of the Galaxy’s globular clusters. Merging our dynamical analysis with complementary chronochemical studies, will allow us to uncover the remaining secrets of the accretion history of the Milky Way.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"9 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138363","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}
Pub Date : 2026-02-06DOI: 10.1051/0004-6361/202558398
R. Fuentetaja, C. Cabezas, M. Agúndez, B. Tercero, N. Marcelino, P. de Vicente, J. Cernicharo
We report the detection of the polycyclic aromatic hydrocarbon (PAH) 1H-cyclopent[cd]indene (c-C11H8) in TMC-1 with the QUIJOTE line survey. We detected 22 independent lines corresponding to 88 rotational transitions with quantum numbers ranging from J = 19 up to J = 24 and Ka ≤ 5 in the Q-band range. The identification of this new PAH was based on the agreement between the rotational parameters derived from the analysis of the lines and those obtained by quantum chemical calculations. The column density derived for 1H-cyclopent[cd]indene is (6.0 ± 0.5) × 1012 cm−2, with a rotational temperature of 9 K. Its abundance is high, as is that of the rest of the PAHs, but it is the lowest of all those detected to date in TMC-1, being 2.66 times less abundant than indene and 4.66 times less than phenalene. This result will help us to better understand the growth of five- and six-membered rings in dark clouds. Chemical models explaining their formation through the bottom-up model are still very incomplete and require further experimental and theoretical effort. Even so, the most likely formation reactions would occur between the smallest rings with small hydrocarbons; the most probable reaction for the formation of cyclopentindene is that between indene and C2H, C2H3, and/or their cation.
{"title":"Discovery of 1H-cyclopent[cd]indene (c-C11H8) in TMC-1 with the QUIJOTE line survey: A new three-ringed polycyclic aromatic hydrocarbon★","authors":"R. Fuentetaja, C. Cabezas, M. Agúndez, B. Tercero, N. Marcelino, P. de Vicente, J. Cernicharo","doi":"10.1051/0004-6361/202558398","DOIUrl":"https://doi.org/10.1051/0004-6361/202558398","url":null,"abstract":"We report the detection of the polycyclic aromatic hydrocarbon (PAH) 1<i>H<i/>-cyclopent[<i>cd<i/>]indene (<i>c<i/>-C<sub>11<sub/>H<sub>8<sub/>) in TMC-1 with the QUIJOTE line survey. We detected 22 independent lines corresponding to 88 rotational transitions with quantum numbers ranging from <i>J<i/> = 19 up to <i>J<i/> = 24 and <i>K<i/><sub><i>a<i/><sub/> ≤ 5 in the <i>Q<i/>-band range. The identification of this new PAH was based on the agreement between the rotational parameters derived from the analysis of the lines and those obtained by quantum chemical calculations. The column density derived for 1<i>H<i/>-cyclopent[<i>cd<i/>]indene is (6.0 ± 0.5) × 10<sup>12<sup/> cm<sup>−2<sup/>, with a rotational temperature of 9 K. Its abundance is high, as is that of the rest of the PAHs, but it is the lowest of all those detected to date in TMC-1, being 2.66 times less abundant than indene and 4.66 times less than phenalene. This result will help us to better understand the growth of five- and six-membered rings in dark clouds. Chemical models explaining their formation through the bottom-up model are still very incomplete and require further experimental and theoretical effort. Even so, the most likely formation reactions would occur between the smallest rings with small hydrocarbons; the most probable reaction for the formation of cyclopentindene is that between indene and C<sub>2<sub/>H, C<sub>2<sub/>H<sub>3<sub/>, and/or their cation.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"33 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138366","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}
Pub Date : 2026-02-06DOI: 10.1051/0004-6361/202555190
X. Song, P. Weltevrede, J. van Leeuwen, G. Wright, M. Keith
Our understanding of the elusive radio-pulsar emission mechanism would be deepened by determining the locality of the emission. Pulsars in which the two poles interact might help us to solve this challenge. We report the discovery of interacting emission between the main and the inter-pulse in two pulsars, J1842+0358 and J1926+0737, based on FAST and MeerKAT data. When the emission is bright in one pulse, it is dim in the other. Even when split into just two groups (strong versus weak), the anti-correlated brightness can change by a factor of ≳2. Both sources furthermore show the same quasi-periodic modulation from the main and inter-pulse at timescales exceeding 100 pulse periods. The longitude stationary modulation from at least one pulse suggests that it is a key signature for inter-pulse pulsars with a main and inter-pulse interaction. If the interaction occurs within an isolated magnetosphere without external influences, either communication between the opposite poles is required, or global changes drive both. This detailed study of these two sources was only made possible by an improved sensitivity. The fact that both show two-pole modulation strongly suggests that this is a general phenomenon in inter-pulse pulsars. In regular pulsars, only one pole is visible, and a number of these regular pulsars show correlated changes between the profile and the spin-down rate that are also thought to be caused by global magnetospheric changes. Our results strengthen the case that these interactive magnetospheres are common to all pulsars.
{"title":"Main and inter-pulse interaction in PSRs J1842+0358 and J1926+0737: evidence of inter-pole communication","authors":"X. Song, P. Weltevrede, J. van Leeuwen, G. Wright, M. Keith","doi":"10.1051/0004-6361/202555190","DOIUrl":"https://doi.org/10.1051/0004-6361/202555190","url":null,"abstract":"Our understanding of the elusive radio-pulsar emission mechanism would be deepened by determining the locality of the emission. Pulsars in which the two poles interact might help us to solve this challenge. We report the discovery of interacting emission between the main and the inter-pulse in two pulsars, J1842+0358 and J1926+0737, based on FAST and MeerKAT data. When the emission is bright in one pulse, it is dim in the other. Even when split into just two groups (strong versus weak), the anti-correlated brightness can change by a factor of ≳2. Both sources furthermore show the same quasi-periodic modulation from the main and inter-pulse at timescales exceeding 100 pulse periods. The longitude stationary modulation from at least one pulse suggests that it is a key signature for inter-pulse pulsars with a main and inter-pulse interaction. If the interaction occurs within an isolated magnetosphere without external influences, either communication between the opposite poles is required, or global changes drive both. This detailed study of these two sources was only made possible by an improved sensitivity. The fact that both show two-pole modulation strongly suggests that this is a general phenomenon in inter-pulse pulsars. In regular pulsars, only one pole is visible, and a number of these regular pulsars show correlated changes between the profile and the spin-down rate that are also thought to be caused by global magnetospheric changes. Our results strengthen the case that these interactive magnetospheres are common to all pulsars.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"22 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138364","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}
Pub Date : 2026-02-06DOI: 10.1051/0004-6361/202554555
J. A. Acevedo Barroso, B. Clément, F. Courbin, R. Gavazzi, C. Lemon, K. Rojas, D. Scott, S. Gwyn, F. Hammer, M. J. Hudson, E. A. Magnier
Recent wide-field galaxy surveys have led to an explosion in the number of galaxy-scale strong gravitational lens candidates. However, the vast majority of them feature massive luminous red galaxies as the main deflectors, with late-type galaxies being vastly under-represented. This work presents a dedicated search for lensing by edge-on late-type galaxies in the Ultraviolet Near Infrared Optical Northern Survey (UNIONS). The search covers 3600 deg2 of r-band observations taken from the Canada-France-Hawaii Telescope. We considered all sources with magnitudes in the range 17 < r < 20.5, without any colour pre-selection, yielding a parent sample of seven million sources. We characterised our parent sample via the visual inspection of 120 000 sources selected at random. From it, we estimate, with a 68% confidence interval, that 1 in every 30 000 sources is an edge-on lens candidate, with at least eight high-quality candidates in the parent sample. This corresponds to one candidate per 17 000 edge-on late-type galaxies. Our search relied on a convolutional neural network (CNN) to select a reduced sample of candidates, which we followed with a visual inspection to curate the final sample. The CNN was trained from scratch using simulated r-band observations of edge-on lenses, and real observations of non-lenses. We found 61 good edge-on lens candidates using the CNN. Moreover, combining the CNN candidates with those found serendipitously and those identified while characterising the parent sample, we discovered 4 grade A, 20 grade B, and 58 grade C edge-on lens candidates, effectively doubling the known sample of these systems. We also discovered 16 grade A, 16 grade B, and 18 grade C lens candidates of other types. Finally, based on the characterisation of the parent sample, we estimate that our search found around 60% of the bright grade A and B edge-on lens candidates within the parent sample.
{"title":"Searching for strong lensing by late-type galaxies in UNIONS","authors":"J. A. Acevedo Barroso, B. Clément, F. Courbin, R. Gavazzi, C. Lemon, K. Rojas, D. Scott, S. Gwyn, F. Hammer, M. J. Hudson, E. A. Magnier","doi":"10.1051/0004-6361/202554555","DOIUrl":"https://doi.org/10.1051/0004-6361/202554555","url":null,"abstract":"Recent wide-field galaxy surveys have led to an explosion in the number of galaxy-scale strong gravitational lens candidates. However, the vast majority of them feature massive luminous red galaxies as the main deflectors, with late-type galaxies being vastly under-represented. This work presents a dedicated search for lensing by edge-on late-type galaxies in the Ultraviolet Near Infrared Optical Northern Survey (UNIONS). The search covers 3600 deg<sup>2<sup/> of <i>r<i/>-band observations taken from the Canada-France-Hawaii Telescope. We considered all sources with magnitudes in the range 17 < <i>r<i/> < 20.5, without any colour pre-selection, yielding a parent sample of seven million sources. We characterised our parent sample via the visual inspection of 120 000 sources selected at random. From it, we estimate, with a 68% confidence interval, that 1 in every 30 000 sources is an edge-on lens candidate, with at least eight high-quality candidates in the parent sample. This corresponds to one candidate per 17 000 edge-on late-type galaxies. Our search relied on a convolutional neural network (CNN) to select a reduced sample of candidates, which we followed with a visual inspection to curate the final sample. The CNN was trained from scratch using simulated <i>r<i/>-band observations of edge-on lenses, and real observations of non-lenses. We found 61 good edge-on lens candidates using the CNN. Moreover, combining the CNN candidates with those found serendipitously and those identified while characterising the parent sample, we discovered 4 grade A, 20 grade B, and 58 grade C edge-on lens candidates, effectively doubling the known sample of these systems. We also discovered 16 grade A, 16 grade B, and 18 grade C lens candidates of other types. Finally, based on the characterisation of the parent sample, we estimate that our search found around 60% of the bright grade A and B edge-on lens candidates within the parent sample.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"211 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138365","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}
Pub Date : 2026-02-05DOI: 10.1051/0004-6361/202557443
Christian P. Clear, Peter Uylings, Ton Raassen
Aims. This work reports calculated transition probabilities for spectral lines of singly ionised nickel (Ni II) incorporating newly determined experimental energy levels, addressing critical gaps in atomic data required for astrophysical spectroscopy and plasma diagnostics.Methods. Transition probabilities of Ni II were calculated using the semi-empirical orthogonal operator method for both odd and even energy levels. Calculated eigenvalues were fine-tuned to experimental energy levels, determined using Fourier transform spectroscopy, further increasing the accuracy of these calculated transition probabilities.Results. In total, transition probabilities have been calculated for nearly 118 000 electric dipole transitions between 361 even and 735 odd levels. The resulting transition probabilities show strong agreement with existing experimental and semi-empirical data, while offering improved consistency and coverage across a wide range of line strengths. The calculated transitions span the far-infrared to the vacuum ultraviolet spectral regions, providing extensive coverage for astrophysical applications. This dataset significantly enhances the calculated atomic data available for Ni II and represents a critical contribution to the advancement of our understanding of astrophysical phenomena through improved spectroscopic analysis.
{"title":"Calculated oscillator strengths and transition probabilities of singly ionised nickel (Ni II)","authors":"Christian P. Clear, Peter Uylings, Ton Raassen","doi":"10.1051/0004-6361/202557443","DOIUrl":"https://doi.org/10.1051/0004-6361/202557443","url":null,"abstract":"<i>Aims<i/>. This work reports calculated transition probabilities for spectral lines of singly ionised nickel (Ni II) incorporating newly determined experimental energy levels, addressing critical gaps in atomic data required for astrophysical spectroscopy and plasma diagnostics.<i>Methods<i/>. Transition probabilities of Ni II were calculated using the semi-empirical orthogonal operator method for both odd and even energy levels. Calculated eigenvalues were fine-tuned to experimental energy levels, determined using Fourier transform spectroscopy, further increasing the accuracy of these calculated transition probabilities.<i>Results<i/>. In total, transition probabilities have been calculated for nearly 118 000 electric dipole transitions between 361 even and 735 odd levels. The resulting transition probabilities show strong agreement with existing experimental and semi-empirical data, while offering improved consistency and coverage across a wide range of line strengths. The calculated transitions span the far-infrared to the vacuum ultraviolet spectral regions, providing extensive coverage for astrophysical applications. This dataset significantly enhances the calculated atomic data available for Ni II and represents a critical contribution to the advancement of our understanding of astrophysical phenomena through improved spectroscopic analysis.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"160 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146121989","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}
Context. As an unmagnetized planet, Venus lacks an intrinsic magnetic field, leading to the direct interaction with the solar wind, which results in differences in physical processes within its magnetosphere–ionosphere (MI) system compared to Earth. With intense solar wind disturbances, it has been suggested that interplanetary coronal mass ejections (ICMEs) have a pronounced effect on Venus.Aims. This study aims to investigate the responses of the Venusian plasma environment to ICMEs. A simulation driven by a real ICME event that occurred on 5 November 2011, was conducted to systematically and quantitatively analyze the plasma processes in Venusian magnetosphere. During this event, the solar wind dynamic pressure at the model input increased by a factor of up to 4.8, while the interplanetary magnetic field (IMF) strength was enhanced by a factor of 1.9.Methods. The numerical simulation for Venusian plasma environment uses a multi-fluid global magnetohydrodynamics (MHD) model, coupled with the uniform neutral atmosphere. Utilizing the upstream magnetic field data from VEX and idealized solar wind plasma parameters as model inputs, we examine the response of Venusian plasma environment after the ICME arrival.Results. Venusian plasma environment and boundaries respond rapidly on the order of minutes. During the ICME, the subsolar bow shock location exhibits an inverse-linear proportionality to the fast magnetosonic Mach number. Meanwhile, the variation in boundaries’ locations demonstrates that high solar wind dynamic pressure and an enhanced IMF display compressive and expanding effects, respectively. The total integral of the ions’ escape rate shows that under ICME passage, the O+ escape rate of Venus exhibits a sustained increase, from 6.0 × 1024 s−1 to 3.0 × 1025 s−1. Both solar wind dynamic pressure and IMF strength enhance ion escape, with dynamic pressure dominating this process.Conclusions. The simulation driven by a real ICME event demonstrates severe, rapid, and complex responses of Venusian plasma environments, accompanied by an order-of-magnitude enhancement O+ escape rate. These results could advance the understanding of the long-term evolution of terrestrial planets and provides references for the scientific targets of future missions.
{"title":"Response of Venusian plasma environment to the interplanetary coronal mass ejections on 5 November 2011: A magnetohydrodynamics simulation study","authors":"Jinshu Cai, Tong Dang, Jiuhou Lei, Binzheng Zhang, Zhonghua Yao, Junjie Chen, Xiaohang Xu, Sudong Xiao, Tielong Zhang","doi":"10.1051/0004-6361/202555227","DOIUrl":"https://doi.org/10.1051/0004-6361/202555227","url":null,"abstract":"<i>Context<i/>. As an unmagnetized planet, Venus lacks an intrinsic magnetic field, leading to the direct interaction with the solar wind, which results in differences in physical processes within its magnetosphere–ionosphere (MI) system compared to Earth. With intense solar wind disturbances, it has been suggested that interplanetary coronal mass ejections (ICMEs) have a pronounced effect on Venus.<i>Aims<i/>. This study aims to investigate the responses of the Venusian plasma environment to ICMEs. A simulation driven by a real ICME event that occurred on 5 November 2011, was conducted to systematically and quantitatively analyze the plasma processes in Venusian magnetosphere. During this event, the solar wind dynamic pressure at the model input increased by a factor of up to 4.8, while the interplanetary magnetic field (IMF) strength was enhanced by a factor of 1.9.<i>Methods<i/>. The numerical simulation for Venusian plasma environment uses a multi-fluid global magnetohydrodynamics (MHD) model, coupled with the uniform neutral atmosphere. Utilizing the upstream magnetic field data from VEX and idealized solar wind plasma parameters as model inputs, we examine the response of Venusian plasma environment after the ICME arrival.<i>Results<i/>. Venusian plasma environment and boundaries respond rapidly on the order of minutes. During the ICME, the subsolar bow shock location exhibits an inverse-linear proportionality to the fast magnetosonic Mach number. Meanwhile, the variation in boundaries’ locations demonstrates that high solar wind dynamic pressure and an enhanced IMF display compressive and expanding effects, respectively. The total integral of the ions’ escape rate shows that under ICME passage, the O<sup>+<sup/> escape rate of Venus exhibits a sustained increase, from 6.0 × 10<sup>24<sup/> s<sup>−1<sup/> to 3.0 × 10<sup>25<sup/> s<sup>−1<sup/>. Both solar wind dynamic pressure and IMF strength enhance ion escape, with dynamic pressure dominating this process.<i>Conclusions<i/>. The simulation driven by a real ICME event demonstrates severe, rapid, and complex responses of Venusian plasma environments, accompanied by an order-of-magnitude enhancement O<sup>+<sup/> escape rate. These results could advance the understanding of the long-term evolution of terrestrial planets and provides references for the scientific targets of future missions.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"23 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146121987","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}
Pub Date : 2026-02-05DOI: 10.1051/0004-6361/202557225
M. Ávila-Bravo, C. Charalambous, C. Aguilera-Gómez
Context. The presence of a stellar companion can strongly influence the architecture and long-term stability of planetary systems. Motivated by the discovery of exoplanets exhibiting extremely high eccentricities (e ≥ 0.8) in systems with a binary companion, we investigated how planetary orbits around one star (S-type configuration) evolve under the gravitational perturbations of the companion.Aims. We assess the role of a stellar companion in shaping the orbital evolution of S-type planets and to explore whether dynamical interactions in such environments can account for the formation of highly eccentric planets.Methods. We performed a suite of N-body simulations, modeling systems initially composed of three Jupiter-mass planets on nearly circular, coplanar orbits around the primary star. We systematically varied the semimajor axis, eccentricity, and inclination of the stellar companion, to characterize the conditions under which extreme eccentricities can be excited.Results. Our results show that dynamical processes such as planet–planet scattering and secular mechanisms – including the von Zeipel–Kozai–Lidov effect induced by the binary – often act together to produce abrupt and significant changes in planetary orbital evolution, with the outcome strongly dependent on the binary separation. The binary’s eccentricity primarily dictates the number of surviving planets, while its inclination not only governs the final eccentricities of those survivors but also drives their orbits to align with the binary plane. Our simulations successfully reproduce the high eccentricities and compact orbits observed in four observed systems, and show close agreement between the modeled configurations and the actual systems.
{"title":"Planetary architectures under the influence of a stellar binary","authors":"M. Ávila-Bravo, C. Charalambous, C. Aguilera-Gómez","doi":"10.1051/0004-6361/202557225","DOIUrl":"https://doi.org/10.1051/0004-6361/202557225","url":null,"abstract":"<i>Context<i/>. The presence of a stellar companion can strongly influence the architecture and long-term stability of planetary systems. Motivated by the discovery of exoplanets exhibiting extremely high eccentricities (<i>e<i/> ≥ 0.8) in systems with a binary companion, we investigated how planetary orbits around one star (S-type configuration) evolve under the gravitational perturbations of the companion.<i>Aims<i/>. We assess the role of a stellar companion in shaping the orbital evolution of S-type planets and to explore whether dynamical interactions in such environments can account for the formation of highly eccentric planets.<i>Methods<i/>. We performed a suite of <i>N<i/>-body simulations, modeling systems initially composed of three Jupiter-mass planets on nearly circular, coplanar orbits around the primary star. We systematically varied the semimajor axis, eccentricity, and inclination of the stellar companion, to characterize the conditions under which extreme eccentricities can be excited.<i>Results<i/>. Our results show that dynamical processes such as planet–planet scattering and secular mechanisms – including the von Zeipel–Kozai–Lidov effect induced by the binary – often act together to produce abrupt and significant changes in planetary orbital evolution, with the outcome strongly dependent on the binary separation. The binary’s eccentricity primarily dictates the number of surviving planets, while its inclination not only governs the final eccentricities of those survivors but also drives their orbits to align with the binary plane. Our simulations successfully reproduce the high eccentricities and compact orbits observed in four observed systems, and show close agreement between the modeled configurations and the actual systems.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"6 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146121985","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}
Context. Solar blowout jets are a distinct subclass of ubiquitous extreme-ultraviolet (EUV) and X-ray coronal jets.Aims. Most existing models of blowout jets prescribe initial magnetic-field configurations and apply ad hoc changes in the photosphere to trigger the jets. In contrast, we aim for a self-consistent magneto-convective description of the jet initiation.Methods. We employed a 3D radiation magnetohydrodynamic (MHD) model of a solar coronal hole region using the MURaM code. The computational domain extends from the upper convection zone to the lower corona. We synthesized the emission in the EUV and X-ray for direct comparison with observations and examined the evolution of the magnetic-field structure of the event.Results. In the simulation a twisted flux tube forms self-consistently, emerges through the surface, and interacts with the preexisting open field. Initially, the resulting jet is of the standard type with a narrow spire. The release of the twist into the open field causes a broadening of the jet spire, turning the jet into a blowout type. At the same time, this creates a fast heating front, propagating at the local Alfvén speed. The properties of the modeled jet closely match those of the observed blowout jets: a slow (∼180 km s−1) mass upflow and a fast (∼500 km s−1) propagating front form, the latter being a signature of the heating front. Also, the timing of the jet with respect to flux emergence and subsequent cancellation matches observations.Conclusions. Near-surface magneto-convection self-consistently generates a twisted flux tube that emerges through the photosphere. The tube then interacts with the preexisting magnetic field by means of interchange reconnection. This transfers the twist to the open field and produces a blowout jet that matches the main characteristics of that found in observations.
上下文。太阳喷流是普遍存在的极紫外（EUV）和x射线日冕喷流的一个独特的亚类。大多数现有的喷流模型都规定了初始磁场结构，并应用光球的特殊变化来触发喷流。相反，我们的目标是对喷流起始的自洽磁对流描述。我们利用MURaM代码建立了太阳日冕空穴区域的三维辐射磁流体动力学（MHD）模型。计算范围从上对流区延伸到下日冕区。我们合成了EUV和x射线的发射，与观测结果进行了直接比较，并研究了事件的磁场结构演变。在模拟中，一个扭曲的磁通管自一致地形成，从表面出现，并与预先存在的开放场相互作用。最初，产生的射流是带有窄尖顶的标准射流。扭转的释放进入空旷的区域，导致喷流尖顶变宽，使喷流变成井喷型。同时，这产生了一个快速的加热锋，以当地的阿尔夫温速度传播。模拟喷流的特性与观测到的喷流非常吻合：缓慢（~ 180 km s - 1）的质量上升流和快速（~ 500 km s - 1）的传播锋形式，后者是加热锋的特征。此外，射流的时间与通量的出现和随后的消除相匹配。结论。近表面磁对流自一致地产生一个扭曲的通量管，通过光球出现。然后，管通过交换重连接的方式与预先存在的磁场相互作用。这将扭曲转移到开放场，并产生与观测中发现的主要特征相匹配的喷流。
{"title":"A self-consistent 3D magnetohydrodynamic model producing a solar blowout jet","authors":"Yajie Chen, Hardi Peter, Damien Przybylski, Lakshmi Pradeep Chitta, Sudip Mandal","doi":"10.1051/0004-6361/202556660","DOIUrl":"https://doi.org/10.1051/0004-6361/202556660","url":null,"abstract":"<i>Context.<i/> Solar blowout jets are a distinct subclass of ubiquitous extreme-ultraviolet (EUV) and X-ray coronal jets.<i>Aims.<i/> Most existing models of blowout jets prescribe initial magnetic-field configurations and apply ad hoc changes in the photosphere to trigger the jets. In contrast, we aim for a self-consistent magneto-convective description of the jet initiation.<i>Methods.<i/> We employed a 3D radiation magnetohydrodynamic (MHD) model of a solar coronal hole region using the MURaM code. The computational domain extends from the upper convection zone to the lower corona. We synthesized the emission in the EUV and X-ray for direct comparison with observations and examined the evolution of the magnetic-field structure of the event.<i>Results.<i/> In the simulation a twisted flux tube forms self-consistently, emerges through the surface, and interacts with the preexisting open field. Initially, the resulting jet is of the standard type with a narrow spire. The release of the twist into the open field causes a broadening of the jet spire, turning the jet into a blowout type. At the same time, this creates a fast heating front, propagating at the local Alfvén speed. The properties of the modeled jet closely match those of the observed blowout jets: a slow (∼180 km s<sup>−1<sup/>) mass upflow and a fast (∼500 km s<sup>−1<sup/>) propagating front form, the latter being a signature of the heating front. Also, the timing of the jet with respect to flux emergence and subsequent cancellation matches observations.<i>Conclusions.<i/> Near-surface magneto-convection self-consistently generates a twisted flux tube that emerges through the photosphere. The tube then interacts with the preexisting magnetic field by means of interchange reconnection. This transfers the twist to the open field and produces a blowout jet that matches the main characteristics of that found in observations.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"28 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146121988","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}
Pub Date : 2026-02-05DOI: 10.1051/0004-6361/202556462
Nuno Moedas, Maria Pia Di Mauro
Context. Procyon A is an F-type main-sequence star in a binary system. It has been the subject of numerous ground-based and space-based observing campaigns, providing precise classical constraints, including a well-determined mass. It was also among the first stars in which individual frequencies were detected, making it a crucial benchmark for F-type stars.Aims. Our goal is to investigate the surface effect, namely the discrepancy between observed and model oscillation frequencies due to inadequate modeling of the surface stellar layers, which is especially important in F-type stars. Using Procyon A as a case study, we aim to understand how different surface correction prescriptions impact the inference of the fundamental properties of this star, and to compare the results with those obtained when the surface corrections are neglected.Methods. We inferred the fundamental stellar properties by employing a grid of models computed with Modules for Experiments in Stellar Astrophysics (MESA), including gravitational settling, radiative accelerations, and turbulent mixing. We selected the best-fit models using the Asteroseismic Inference on a Massive Scale (AIMS) code, taking into account different methods to fit the individual frequencies.Results. We find that the use of surface corrections can introduce uncertainties of up to 7% in the inferred stellar mass. We obtain the most reliable stellar mass estimates when using frequency ratios, the Sonoi surface correction, or direct fitting of the individual frequencies.Conclusions. Our results indicate that the surface effects in F-type stars differ from those found in the Sun and in solar-like stars, highlighting the need for caution when considering the surface corrections for these stars.
{"title":"Studying the surface effect in Procyon A as an F-type star","authors":"Nuno Moedas, Maria Pia Di Mauro","doi":"10.1051/0004-6361/202556462","DOIUrl":"https://doi.org/10.1051/0004-6361/202556462","url":null,"abstract":"<i>Context.<i/> Procyon A is an F-type main-sequence star in a binary system. It has been the subject of numerous ground-based and space-based observing campaigns, providing precise classical constraints, including a well-determined mass. It was also among the first stars in which individual frequencies were detected, making it a crucial benchmark for F-type stars.<i>Aims.<i/> Our goal is to investigate the surface effect, namely the discrepancy between observed and model oscillation frequencies due to inadequate modeling of the surface stellar layers, which is especially important in F-type stars. Using Procyon A as a case study, we aim to understand how different surface correction prescriptions impact the inference of the fundamental properties of this star, and to compare the results with those obtained when the surface corrections are neglected.<i>Methods.<i/> We inferred the fundamental stellar properties by employing a grid of models computed with Modules for Experiments in Stellar Astrophysics (MESA), including gravitational settling, radiative accelerations, and turbulent mixing. We selected the best-fit models using the Asteroseismic Inference on a Massive Scale (AIMS) code, taking into account different methods to fit the individual frequencies.<i>Results.<i/> We find that the use of surface corrections can introduce uncertainties of up to 7% in the inferred stellar mass. We obtain the most reliable stellar mass estimates when using frequency ratios, the Sonoi surface correction, or direct fitting of the individual frequencies.<i>Conclusions.<i/> Our results indicate that the surface effects in F-type stars differ from those found in the Sun and in solar-like stars, highlighting the need for caution when considering the surface corrections for these stars.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"83 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122419","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}
Pub Date : 2026-02-04DOI: 10.1051/0004-6361/202556078
P. Cataldi, S. Pedrosa, L. J. Pellizza, D. Ceverino, L. A. Bignone
Context. The James Webb Space Telescope has found an unexpected population of high-mass galaxies (log(M★/M⊙)≳10) with extremely small effective radii (∼100 pc) at z ≳ 6. Also, the existence of an unusual size–mass relation has been claimed. These observations are only partially reproduced by current models, and the physics responsible for the observed relations is still under debate.Aims. We aim to understand the physical mechanisms governing the size evolution of galaxies, and its dependence on their properties in the early Universe. We expect to unveil the formation channels of the observed compact galaxies.Methods. We analysed 7605 snapshots for 169 galaxies of the state-of-the-art cosmological simulation suite FIRSTLIGHT, focusing on the high-redshift stellar size–mass relation and its evolution with a resolution of tens of parsecs.Results. We find that galaxies undergo an expansion–compaction–re-expansion process. The sizes attained by galaxies during compaction are comparable with those observed. This process operates in a specific mass range; compaction starts at and ends at . In between these masses, the size–mass relation becomes inverted, with a negative slope. The physical mechanism driving this process in our simulations involves a self-reinforced inflow of gas from the outer regions, which triggers a strong, localised starburst at the centre (within 1 kpc). This contraction continues until conditions favour star formation in a broader area, and the normal inside-out growth pattern resumes.Conclusions. We present evidence for the existence of a universal wet compaction operating at Cosmic Dawn. This mechanism is driven by spherical accretion triggered by the change of the state of the central matter of galaxies, from dark matter- to baryon-dominated. We also propose an analytical expression for the infall process, suitable for use in semi-analytic models. Contrary to low-redshift galaxies, in high-redshift systems compaction ends without gas depletion and star-formation quenching.
{"title":"Galaxy sizes and compactness at Cosmic Dawn","authors":"P. Cataldi, S. Pedrosa, L. J. Pellizza, D. Ceverino, L. A. Bignone","doi":"10.1051/0004-6361/202556078","DOIUrl":"https://doi.org/10.1051/0004-6361/202556078","url":null,"abstract":"<i>Context.<i/> The James Webb Space Telescope has found an unexpected population of high-mass galaxies (log(<i>M<i/><sup>★<sup/>/M<sub>⊙<sub/>)≳10) with extremely small effective radii (∼100 pc) at <i>z<i/> ≳ 6. Also, the existence of an unusual size–mass relation has been claimed. These observations are only partially reproduced by current models, and the physics responsible for the observed relations is still under debate.<i>Aims.<i/> We aim to understand the physical mechanisms governing the size evolution of galaxies, and its dependence on their properties in the early Universe. We expect to unveil the formation channels of the observed compact galaxies.<i>Methods.<i/> We analysed 7605 snapshots for 169 galaxies of the state-of-the-art cosmological simulation suite FIRSTLIGHT, focusing on the high-redshift stellar size–mass relation and its evolution with a resolution of tens of parsecs.<i>Results.<i/> We find that galaxies undergo an expansion–compaction–re-expansion process. The sizes attained by galaxies during compaction are comparable with those observed. This process operates in a specific mass range; compaction starts at and ends at . In between these masses, the size–mass relation becomes inverted, with a negative slope. The physical mechanism driving this process in our simulations involves a self-reinforced inflow of gas from the outer regions, which triggers a strong, localised starburst at the centre (within 1 kpc). This contraction continues until conditions favour star formation in a broader area, and the normal inside-out growth pattern resumes.<i>Conclusions.<i/> We present evidence for the existence of a universal wet compaction operating at Cosmic Dawn. This mechanism is driven by spherical accretion triggered by the change of the state of the central matter of galaxies, from dark matter- to baryon-dominated. We also propose an analytical expression for the infall process, suitable for use in semi-analytic models. Contrary to low-redshift galaxies, in high-redshift systems compaction ends without gas depletion and star-formation quenching.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"117 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115798","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}
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