Astronomy & Astrophysics最新文献

{"title":"Great Balls of FIRE","authors":"T. Bruel, A. Lamberts, C. L. Rodriguez, R. Feldmann, M. Y. Grudić, J. Moreno","doi":"10.1051/0004-6361/202554454","DOIUrl":"https://doi.org/10.1051/0004-6361/202554454","url":null,"abstract":"<i>Context<i/>. The detection of over a hundred gravitational wave signals from double compacts objects, reported by the LIGO-Virgo-KAGRA Collaboration, have confirmed the existence of such binaries with tight orbits. Two main formation channels are generally considered to explain the formation of these merging binary black holes (BBHs): the isolated evolution of stellar binaries and the dynamical assembly in dense environments, namely, star clusters. Although their relative contributions remain unclear, several analyses indicate that the detected BBH mergers probably originate from a mixture of these two distinct scenarios.<i>Aims<i/>. We study the formation of massive star clusters across time and on a cosmological scale to estimate the contribution of these dense stellar structures to the overall population of BBH mergers.<i>Methods<i/>. To this end, we propose three different models of massive star cluster formation based on results obtained with zoom-in simulations of individual galaxies. We applied these models to a large sample of realistic galaxies identified in the (22.1 Mpc)<sup>3<sup/> cosmological volume simulation FIREbox. Each galaxy in this simulation has a unique star formation rate, with its own history of halo mergers and metallicity evolution. Combined with predictions obtained with the Cluster Monte Carlo code for stellar dynamics, we were able to estimate populations of dynamically formed BBHs in a collection of realistic galaxies.<i>Results<i/>. Across our three models, we inferred a local merger rate of BBHs formed in massive star clusters consistently in the range 1–10 Gpc<sup>−3<sup/>yr<sup>−1<sup/>. Compared with the local BBH merger rate inferred by the LIGO-Virgo-KAGRA Collaboration (in the range 17.9–44 Gpc<sup>−3<sup/>yr<sup>−1<sup/> at <i>z<i/> = 0.2), this could potentially represent up to half of all BBH mergers in the nearby Universe. This shows the importance of this formation channel in the astrophysical production of merging BBHs. We find that these events preferentially take place around cosmic noon and in the most massive galaxies.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"86 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145127781","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":"Plasma lens with frequency-dependent dispersion measure effects on fast radio bursts","authors":"Yu-Bin Wang, Xia Zhou, Abdusattar Kurban","doi":"10.1051/0004-6361/202453112","DOIUrl":"https://doi.org/10.1051/0004-6361/202453112","url":null,"abstract":"Radio signals propagating through inhomogeneous plasma media deviate from their original paths, producing frequency-dependent magnification effects. In this paper, after reviewing the classical plasma-lensing theory, we have found a fundamental contradiction: the classical model assumes that the distribution of lensing plasma medium is related to the frequency-independent image position; however, our analysis demonstrates that both the image position (<i>θ<i/>(<i>ν<i/>)) and dispersion measure (DM(<i>ν<i/>)) are inherently frequency-dependent when signals traverse a structured plasma medium. We have been able to resolve this paradox by developing a framework that explicitly incorporates frequency-dependent dispersion measures (DMs) following power-law relationships (DM ∝ <i>ν<i/><sup><i>γ<i/><sup/>). Our analysis shows that the signal magnification decreases systematically with decreasing frequency, offering a plausible explanation for the frequency-dependent peak flux densities observed in fast radio bursts (FRBs), particularly in the case of the repeating FRB 180814.J0422+73. Our results suggest these FRBs could originate from the magnetized compact star magnetospheres. By considering these plasma-lensing effects on the sub-pulses of an FRB across different frequencies, we have the ability to more accurately investigate the intrinsic properties of FRBs via precise measurements of radio signals.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"17 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145127751","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":"SDSS J1001+5027: Strong microlensing-induced chromatic variation caught in the act","authors":"Luis J. Goicoechea, Vyacheslav N. Shalyapin","doi":"10.1051/0004-6361/202556521","DOIUrl":"https://doi.org/10.1051/0004-6361/202556521","url":null,"abstract":"We conducted long-term monitoring of the doubly imaged gravitationally lensed quasar SDSS J1001+5027 consisting of spectro-photometric observations separated by ∼120 days (time delay between both quasar images), as well as test and auxiliary data. This monitoring approach allowed us to reliably find a strong microlensing-induced chromatic variation of the quasar continuum in the period 2022–2025. The ongoing microlensing event has caused the delay-corrected spectral flux ratio in 2025 to have a dramatic changing look, opening the door to very promising observations of the system in the coming years. These future follow-up observations of such a rare event are expected to provide critical information to discuss, among other things, the structure of the inner accretion flow towards the central supermassive black hole in SDSS J1001+5027.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"58 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145127750","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":"Foreground and internal free-free absorption in particle-accelerating colliding-wind binaries","authors":"M. Tasseroul, M. De Becker, A. B. Blanco, P. Benaglia, S. del Palacio","doi":"10.1051/0004-6361/202555803","DOIUrl":"https://doi.org/10.1051/0004-6361/202555803","url":null,"abstract":"<i>Context<i/>. Radio emission from massive binary systems is generally of composite nature, exhibiting both a thermal emission component from the winds and a non-thermal component from relativistic electrons accelerated in the colliding-wind region. Understanding the processes governing their radio spectrum is key to investigating the role of these objects in the production of non-thermal particle populations in our galaxy.<i>Aims<i/>. Our objective is to explore how the processes at work in particle-accelerating colliding-wind binaries (PACWBs) alter their spectral energy distribution, based on a simple phenomenological description. We focus on the role of free–free absorption (FFA) at low frequencies. We use WR 147 as a test case, followed by a tentative extrapolation to more generic behaviour.<i>Methods<i/>. We processed a set of recent Karl G. Jansky Very Large Array data, optimised for spectral analysis, combined with literature measurements at other frequencies. We analysed the radio spectrum, considering a more classical foreground free-free absorption (f-FFA) model along with the first application of an internal free-free absorption (i-FFA) model.<i>Results<i/>. Our results show that the f-FFA model does not reproduce the spectral energy distribution of WR 147 at low frequencies. The i-FFA model is more efficient in providing a more complete description of the spectral energy distribution down to 610 MHz. This model is the only one to account for a change in the spectral index at low frequencies without any exponential drop in flux, as predicted by the f-FFA model. In addition, the upper limit at 150 MHz shows that two turnovers occur in the radio spectrum of WR 147, suggesting the effect of both i-FFA and f-FFA is seen in two regions of the spectrum.<i>Conclusions<i/>. The radio spectrum at low frequencies for very long period systems might display some internally attenuated synchrotron emission, without necessarily being suppressed by a steep exponential cut-off. We propose a generic spectral energy distribution for FFA-affected radio spectra of colliding-wind massive binaries, where the overall spectral shape can be expressed in terms of the relative importance of f-FFA and i-FFA. We also comment on the observational consequences of this generic behaviour in the broader context of the full class of PACWBs.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"23 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145127753","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 late Miocene 10Be anomaly and the possibility of a supernova","authors":"E. Maconi, J. Alves, J. Großschedl, A. Rottensteiner, C. Swiggum, S. Ratzenböck","doi":"10.1051/0004-6361/202556253","DOIUrl":"https://doi.org/10.1051/0004-6361/202556253","url":null,"abstract":"Recent measurements of cosmogenic <sup>10<sup/>Be in deep-ocean ferromanganese crusts from the central and northern Pacific have revealed an anomalous concentration between 11.5 and 9.0 Myr ago, peaking at 10.1 Myr. One possible explanation is a nearby supernova (SN) event. Motivated by this and by the proximity of the Solar System to the Orion star-forming region during that period, we estimated the probability that at least one SN occurred between the onset and peak of the anomaly. Using an open cluster catalog based on <i>Gaia<i/> DR3, we traced back the orbits of 2725 clusters and the Sun over the past 20 Myr and computed the expected number of SN events. We found 19 clusters with a probability greater than 1% each of producing at least one SN within 100 pc of the Sun in the time interval 11.5–10.1 Myr ago. The total cumulative probability exceeds zero at 35 pc from the Sun and increases rapidly with distance, reaching 68% near 100 pc. Two young clusters dominate the SN probability: ASCC 20 contributes most within 70 pc, while OCSN 61 becomes more significant beyond that distance. Our results support the possibility of an SN origin for the <sup>10<sup/>Be anomaly and highlight the importance of additional <sup>10<sup/>Be records from independent terrestrial archives to determine whether the anomaly is of astrophysical or terrestrial origin.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"40 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145127748","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":"Low-velocity large-scale shocks in the infrared dark cloud G035.39-00.33: Bubble-driven cloud-cloud collisions","authors":"G. Cosentino, I. Jiménez-Serra, R. Liu, C.-Y. Law, J. C. Tan, J. D. Henshaw, A. T. Barnes, F. Fontani, P. Caselli, S. Viti","doi":"10.1051/0004-6361/202556057","DOIUrl":"https://doi.org/10.1051/0004-6361/202556057","url":null,"abstract":"<i>Context<i/>. Low-velocity, large-scale shocks impacting on the interstellar medium have been suggested as efficient mechanisms that shape molecular clouds and trigger star formation within them.<i>Aims<i/>. These shocks, both driven by galactic bubbles and/or cloud-cloud collisions, leave specific signatures in the morphology and kinematics of the gas. Observational studies of such signatures are crucial to investigate if and how shocks affect the clouds formation process and trigger their future star formation.<i>Methods<i/>. We have analysed the shocked and dense gas tracers SiO(2−1) and H<sup>13<sup/> CO<sup>+<sup/>(1−0) emission towards the Infrared Dark Cloud G035.39-00.33, using new, larger-scale maps obtained with the 30 m telescope at the Instituto de Radioastronomía Millimétrica.<i>Results<i/>. We find that the dense gas is organised into a northern filament and a southern one that have different velocities and tilted orientations with respect to each other. The two filaments, seen in H<sup>13<sup/> CO<sup>+<sup/>, are spatially separated yet connected by a faint bridge-like feature also seen in a position-velocity diagram extracted across the cloud. This bridge feature, typical of cloud-cloud collisions, also coincides with a very spectrally narrow SiO-traced gas emission. We suggest that the northern filament is interacting with the nearby supernova remnant G035.6-0.4. Towards the southern filament, we also report the presence of a parsec-scale, spectrally narrow SiO emission likely driven by the interaction between this filament and a nearby expanding shell. The shell is visible in the 1.3 GHz and 610 MHz continuum images and our preliminary analysis suggests it may be the relic of a supernova remnant.<i>Conclusions<i/>. We conclude that the two filaments represent the densest part of two colliding clouds, pushed towards each other by nearby supernova remnants. We speculate that this cloud-cloud collision driven by stellar feedback may have assembled the infrared dark cloud. We also evaluate the possibility that star formation may have been triggered within G035.39-00.33 by the cloud-cloud collision.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"58 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145127752","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":"X-ray photodesorption of complex organic molecules in protoplanetary disks","authors":"R. Basalgète, D. Torres-Díaz, A. Lafosse, L. Amiaud, L. Philippe, X. Michaut, J.-H. Fillion, M. Bertin","doi":"10.1051/0004-6361/202555420","DOIUrl":"https://doi.org/10.1051/0004-6361/202555420","url":null,"abstract":"<i>Context<i/>. Nonthermal desorption from interstellar ices induced by X-rays, known as X-ray photodesorption, is a possible route to explain gas phase molecules detected in protoplanetary disks. However, the efficiency of such a process remains to be quantified for organic molecules, such as formic acid, HCOOH.<i>Aims<i/>. We experimentally estimate the X-ray photodesorption yields of intact HCOOH and its photoproducts from its pure ice and when it is mixed in CO-dominated and H<sub>2<sub/>O-dominated ices.<i>Methods<i/>. Ices were grown in an ultrahigh vacuum setup and soft X-rays (530–560 eV) from the SEXTANTS beamline of the SOLEIL synchrotron facility were used to irradiate the ices at 15 K. X-ray photodesorption from the ices was probed in the gas phase of the chamber via quadrupole mass spectrometry. X-ray photodesorption yields were derived from the mass signals; they are expressed in molecules desorbed per incident photon, denoted as molecules photon<sup>−1<sup/> in the manuscript. They were extrapolated and averaged in the 0.53–10 keV range in order to provide yields that can be easily implemented in astrochemical models, referred to as astrophysical yields in the following.<i>Results<i/>. X-ray photodesorption of intact HCOOH at 560 eV is found to be close to our detection limit of 10<sup>−3<sup/> molecules photon<sup>−1<sup/> for pure and mixed-CO ices. When mixed in H<sub>2<sub/>O ices, no clear desorption signal of intact HCOOH is observed. X-ray photodesorption yields of the HCOOH photoproducts, which we attribute to H<sub>2<sub/>O, CO, CO<sub>2<sub/>, HCO, H<sub>2<sub/>CO, and O<sub>2<sub/>, are derived as a function of the ice composition. Possible factors that may explain the relative intensities of the yields are discussed. The astrophysical yields of intact HCOOH from CO-dominated ices vary from ~10<sup>−3<sup/> to ~5 × 10<sup>−6<sup/> molecules photon<sup>−1<sup/> depending on the region of the disk considered. Only upper limits, of the same order of magnitude, can be provided for the desorption of intact HCOOH from H<sub>2<sub/>O-dominated ices.<i>Conclusions<i/>. X-ray photodesorption should enrich the gas phase of the cold regions of protoplanetary disks with organic molecules such as HCOOH. However, as has been suggested in previous studies on CH<sub>3<sub/>OH and CH<sub>3<sub/>CN, X-ray photodesorption from H<sub>2<sub/>O-rich ice surfaces should be less efficient than from CO-rich ice surfaces by a factor that remains to be quantified for HCOOH.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"39 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145103635","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 role of environment in the evolution of disc galaxy density profiles","authors":"M. Mondelin, F. Bournaud, J.-C. Cuillandre, P. Hennebelle","doi":"10.1051/0004-6361/202554840","DOIUrl":"https://doi.org/10.1051/0004-6361/202554840","url":null,"abstract":"Galactic discs are known to have exponential radial profiles in luminosity and in stellar surface density, in their bright inner regions. Nonetheless, their faint outer regions often display a break in the profile, with either a down-bending break or an up-bending break of the density profile. Recent Euclid Early Release Observations have shown that down-bending breaks are very scarce in the Perseus cluster, which was already suspected with poorer statistics in the Virgo cluster. We use hydrodynamic simulations of disc galaxies interacting with a Perseus-like cluster. We show that Type II profiles – corresponding to down-bending disc breaks – can be rapidly eroded by the cluster tidal field on a timescale of approximately 1 Gyr, while Type III profiles – associated with up-bending breaks – and Type I profiles – with no significant break – remain largely unaffected. Type II profiles are eroded through a combination of dynamical processes, including tidal stirring of pre-existing stars by the cluster potential, and triggering of new star formation in the outer disc. Overall, our simulations show that observations of disc breaks across different environments and cosmic epochs are consistent with a coherent evolutionary picture. At high redshift, observations by JWST of disc galaxies reveal early break structures formed in relatively isolated environments. At low redshift, isolated disc galaxies in field environments continue to exhibit these break features, while dense cluster environments, as observed by Euclid in the Perseus cluster, show significant alterations to these profiles. Our findings support a scenario in which down-bending disc break profiles result primarily from internal dynamical processes – such as disc instabilities and resonances – during early formation phases, and are later modified by environmental effects in dense clusters. This interpretation does not require invoking additional mechanisms such as ram-pressure stripping or variations in star formation density thresholds to explain the observed evolution of down-bending breaks among disc galaxies at various redshifts and in various environments.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"60 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145103608","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 infrared jet of M87 observed with JWST","authors":"Jan Röder, Maciek Wielgus, Joseph B. Jensen, Gagandeep S. Anand, R. Brent Tully","doi":"10.1051/0004-6361/202556577","DOIUrl":"https://doi.org/10.1051/0004-6361/202556577","url":null,"abstract":"<i>Aims.<i/> We present the first JWST+NIRCam images of the giant elliptical active galaxy M87 and its jet at 0.90, 1.50, 2.77, and 3.56 μm. We analysed the large-scale jet structure, identifying prominent components, and we determined the near-infrared spectral index.<i>Methods.<i/> The data were calibrated using the standard JWST pipeline. We subtracted a constant background level and a smooth model of the galaxy surface brightness to isolate the jet.<i>Results.<i/> The total image fluxes measured in the NIRCam filters follow the infrared bump pattern seen near 1.6 μm in the spectrum of M87, caused by the surrounding stellar population in the galaxy. The residual jet images broadly agree with the radio to optical synchrotron power law of <i>S<i/><sub><i>λ<i/><sub/> ∝ <i>λ<i/><sup><i>α<i/><sup/> with <i>α<i/> = 0.7 − 1.0. We identified the most upstream knot, L, at a distance of (320 ± 50) mas from the core. The component HST-1, located at (950 ± 50) mas from the core, is transversely resolved. Both the individual images and the spectral index map clearly indicate its double-component substructure with two elements of a similar size and flux density, with centroids separated by (150 ± 20) mas. In addition, it displays a significantly larger spectral index, <i>α<i/>, observed in the downstream component (<i>α<i/><sub>do<sub/> = 0.30) compared to the upstream one (<i>α<i/><sub>up<sub/> = −0.15). We also observed the counter-jet component located about 24 arcsec away from the nucleus.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"130 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145103604","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 magnetism in blue and yellow straggler stars","authors":"S. Hubrig, S. P. Järvinen, I. Ilyin, M. Schöller","doi":"10.1051/0004-6361/202556166","DOIUrl":"https://doi.org/10.1051/0004-6361/202556166","url":null,"abstract":"<i>Context<i/>. Our understanding of the generation of magnetic fields in intermediate-mass and massive OBA stars remains limited. Some theories have proposed that their magnetic fields could be a result of strong binary interactions, including stellar mergers. Blue straggler stars, which lie well beyond the main sequence turn-off point on the colour-magnitude diagram of stellar clusters, are widely theorised to be merger products or interacting binaries and therefore can be considered excellent test targets to get insights into the origin of magnetic fields in stars with radiative envelopes.<i>Aims<i/>. We search for the presence of magnetic fields in a sample of blue and yellow straggler stars listed in the <i>Gaia<i/> DR2-based catalogue of blue straggler stars in open clusters.<i>Methods<i/>. We measured the mean longitudinal magnetic field from high-resolution HARPSpol spectra of five blue straggler and three yellow straggler stars using the least-squares deconvolution technique.<i>Results<i/>. We present the first observational evidence that blue straggler and yellow straggler stars possess magnetic fields of the order of a hundred to a few hundred Gauss. The targets in our sample belong to open clusters of very different ages and metallicities, but we do not detect any relationship between the presence or strength of the detected magnetic field and the cluster characteristics. For the first time, using high-resolution spectropolarimetric observations, a definite detection of a magnetic field is achieved in a Be-shell star, HD 61954. The two yellow straggler stars, HD 62329 and HD 65032, appear to be members in binary systems, whereas the blue straggler star HD 62775 is possibly a triple system. HD 62329 and HD 65032 exhibit in their spectra weak Nd III 6145 lines, which are usually prominent in magnetic Ap and Bp stars. Our observations provide crucial information necessary for testing predictions of existing theories and place strong constraints on the origin of magnetic fields in stars with radiative envelopes.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"120 2 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145103606","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}