Astronomy & Astrophysics最新文献

{"title":"Blue monsters at z > 10: Where all their dust has gone","authors":"A. Ferrara, A. Pallottini, L. Sommovigo","doi":"10.1051/0004-6361/202452707","DOIUrl":"https://doi.org/10.1051/0004-6361/202452707","url":null,"abstract":"The properties of luminous, blue, super-early galaxies (a.k.a. blue monsters) at redshift <i>z<i/> > 10 have been successfully explained by the attenuation-free model (AFM), in which dust is pushed to kiloparsec scales by radiation-driven outflows. As an alternative to AFM, here we assess whether “attenuation-free” conditions can be replaced by a “dust-free” scenario in which dust is produced in very limited amounts and/or later destroyed in the interstellar medium. To this aim, we compare the predicted values of the dust-to-stellar mass ratio, <i>ξ<i/><sub><i>d<i/><sub/>, with those measured in 15 galaxies at <i>z<i/> > 10 from <i>James Webb<i/> Space Telescope (JWST) spectra, when outflows are not included. Our model constrains <i>ξ<i/><sub><i>d<i/><sub/> as a function of several parameters by allowing wide variations in the initial mass function (IMF), dust and metal production, and dust destruction for a set of supernova (SN) progenitor models and explosion energies. We find that log <i>ξ<i/><sub><i>d<i/><sub/> ≈ −2.2 for all systems, which is indicative of the dominant role of SN dust production over destruction in these early galaxies. Such a value is strikingly different from the data, which instead indicates log <i>ξ<i/><sub><i>d<i/><sub/> ≲ −4. We conclude that dust destruction alone can hardly explain the transparency of blue monsters. Other mechanisms, such as outflows, might be required.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"88 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462356","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":"Gamma-ray flares from the jet of the blazar CTA 102 in 2016–2018","authors":"Sanghyun Kim, Sang-Sung Lee, Juan Carlos Algaba, Bindu Rani, Jongho Park, Hyeon-Woo Jeong, Whee Yeon Cheong, Filippo D’Ammando, Anne Lähteenmäki, Merja Tornikoski, Joni Tammi, Venkatessh Ramakrishnan, Iván Agudo, Carolina Casadio, Juan Escudero, Antonio Fuentes, Efthalia Traianou, Ioannis Myserlis, Clemens Thum","doi":"10.1051/0004-6361/202450003","DOIUrl":"https://doi.org/10.1051/0004-6361/202450003","url":null,"abstract":"CTA 102 is a <i>γ<i/>-ray bright blazar that exhibited multiple flares in observations by the Large Area Telescope on board the <i>Fermi<i/> Gamma-Ray Space Telescope during the period of 2016–2018. We present results from the analysis of multi-wavelength light curves with the aim of revealing the nature of <i>γ<i/>-ray flares from the relativistic jet in the blazar. We analysed radio, optical, X-ray, and <i>γ<i/>-ray data obtained in a period from 2012 September 29 to 2018 October 8. We identified six flares in the <i>γ<i/>-ray light curve, showing a harder-when-brighter trend in the <i>γ<i/>-ray spectra. We performed a cross-correlation analysis of the multi-wavelength light curves. We found nearly zero time lags between the <i>γ<i/>-ray and optical and X-ray light curves, implying a common spatial origin for the emission in these bands. We found significant correlations between the <i>γ<i/>-ray and radio light curves as well as negative or positive time lags with the <i>γ<i/>-ray emission lagging or leading the radio during different flaring periods. The time lags between the <i>γ<i/>-ray and radio emission propose the presence of multiple <i>γ<i/>-ray emission sites in the source. As seen in 43 GHz images from the Very Long Baseline Array, two moving disturbances (or shocks) were newly ejected from the radio core. The <i>γ<i/>-ray flares from 2016 to 2017 are temporally coincident with the interaction between a travelling shock and a quasi-stationary one at ∼0.1 mas from the core. The other shock was found to have emerged from the core nearly simultaneously with the <i>γ<i/>-ray flare in 2018. Our results suggest that the <i>γ<i/>-ray flares originated from shock-shock interactions.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"65 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462358","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":"J1721+8842: The first Einstein zigzag lens","authors":"F. Dux, M. Millon, C. Lemon, T. Schmidt, F. Courbin, A. J. Shajib, T. Treu, S. Birrer, K. C. Wong, A. Agnello, A. Andrade, A. Galan, J. Hjorth, E. Paic, S. Schuldt, A. Schweinfurth, D. Sluse, A. Smette, S. H. Suyu","doi":"10.1051/0004-6361/202452970","DOIUrl":"https://doi.org/10.1051/0004-6361/202452970","url":null,"abstract":"We report the discovery of the first example of an Einstein zigzag lens, an extremely rare lensing configuration. In this system, J1721+8842, six images of the same background quasar are formed by two intervening galaxies, one at redshift <i>z<i/><sub>1<sub/> = 0.184 and another at <i>z<i/><sub>2<sub/> = 1.885. Two out of the six multiple images are deflected in opposite directions as they pass the first lens galaxy on one side and the second on the other side – the optical paths forming zigzags between the two deflectors. In this paper we demonstrate that J1721+8842, previously thought to be a lensed dual quasar, is in fact a compound lens, with the more distant lens galaxy also being distorted as an arc by the foreground galaxy. Evidence supporting this unusual lensing scenario includes: (1) identical light curves in all six lensed quasar images obtained from two years of monitoring at the Nordic Optical Telescope; (2) detection of the additional deflector at redshift <i>z<i/><sub>2<sub/> = 1.885 in <i>JWST<i/>/NIRSpec integral field unit data; and (3) a multiple-plane lens model reproducing the observed image positions. This unique configuration offers the opportunity to combine two major lensing cosmological probes, time-delay cosmography and dual source-plane lensing, since J1721+8842 features multiple lensed sources that form two distinct Einstein radii of different sizes, one of which is a variable quasar. We expect to place tight constraints on <i>H<i/><sub>0<sub/> and <i>w<i/> by combining these two probes of the same system. The <i>z<i/><sub>2<sub/> = 1.885 deflector, a quiescent galaxy, is also the highest-redshift strong galaxy-scale lens with a spectroscopic redshift measurement known to date.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"13 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462429","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":"Hydrogenation of acetaldehyde on interstellar ice analogs results in limited destruction","authors":"G. Molpeceres, T. Nguyen, Y. Oba, N. Watanabe","doi":"10.1051/0004-6361/202451990","DOIUrl":"https://doi.org/10.1051/0004-6361/202451990","url":null,"abstract":"<i>Context<i/>. Acetaldehyde (CH<sub>3<sub/>CHO) is one of the most abundant interstellar complex organic molecules and its hydrogenation has important implications in several fundamental processes of interstellar chemistry, such as deuterium fractionation, reactive desorption, or the relation between organic functional groups of detected molecules.<i>Aims<i/>. We seek to determine what the main hydrogenation paths of CH<sub>3<sub/>CHO are. As a partially unsaturated molecule, CH<sub>3<sub/>CHO can have links with more hydrogenated species, such as ethanol (C<sub>2<sub/>H<sub>5<sub/>OH), or with more unsaturated ones, such as ketene (H<sub>2<sub/>CCO).<i>Methods<i/>. We used highly accurate quantum chemical calculations to determine the reaction rate constants for the CH<sub>3<sub/>CHO + H/D reaction. We later studied, using more approximated methods, the fate of the majoritarian product of the reaction, the acetyl radical CH<sub>3<sub/>CO after subsequent reaction with hydrogen or deuterium atoms. Our theoretical results were tested with our experiments on the hydrogenation and deuteration of CH<sub>3<sub/>CHO ice.<i>Results<i/>. We find that acetaldehyde resists hydrogenation, with only a 10% of conversion to products different than CH<sub>3<sub/>CHO. This is due to a predominance of H abstraction at the HCO moiety, with reaction rate constants up to four orders of magnitude higher than the next possible reaction channel, which is hydrogenation at the aldehydic carbon. The formed CH<sub>3<sub/>CO radical experiences barrierless or nearly barrierless reactions in all possible reaction positions, reforming CH<sub>3<sub/>CHO and creating a closed loop that protects the molecule against hydrogenation. We constrained the branching ratios for the second reaction from the experiments. Our experiments agree with the calculations and from the combination of both we can explain the presence of H<sub>2<sub/>CCO, CO, CH4, C<sub>2<sub/>H<sub>5<sub/>OH, H<sub>2<sub/>CO, or CH<sub>3<sub/>OH as minor products at the end of the reaction. We provide recommendations for future modeling efforts.<i>Conclusions<i/>. Our results show limited destruction of acetaldehyde, reinforcing the vision of this molecule as an abundant and resilient COM. From the experiments, we are not able to observe the reactive desorption of this molecule. Our results align with other modeling works, showing that the link between CH<sub>3<sub/>CHO and C<sub>2<sub/>H<sub>5<sub/>OH is not direct. Finally, our results can explain the excess of CH<sub>3<sub/>CDO found in prestellar cores.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"89 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462494","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 MSG model for cloudy sub-stellar atmospheres","authors":"Beatriz Campos Estrada, David A. Lewis, Christiane Helling, Richard A. Booth, Francisco Ardévol Martínez, Uffe G. Jørgensen","doi":"10.1051/0004-6361/202451562","DOIUrl":"https://doi.org/10.1051/0004-6361/202451562","url":null,"abstract":"<i>Context<i/>. State-of-the-art JWST observations are unveiling unprecedented views into the atmospheres of sub-stellar objects in the infrared, further highlighting the importance of clouds. Current forward models struggle to fit the silicate clouds absorption feature at ∼10 µm observed in sub-stellar atmospheres.<i>Aims<i/>. In the MSG model, we aim to couple the MARCS 1D radiative-convective equilibrium atmosphere model with the 1D kinetic, stationary, non-equilibrium cloud formation model DRIFT, also known as StaticWeather, to create a new grid of self-consistent cloudy sub-stellar atmosphere models with microphysical cloud formation. We aim to test if this new grid is able to reproduce the silicate cloud absorption feature at ∼10 µm.<i>Methods<i/>. We modelled sub-stellar atmospheres with effective temperatures in the range <i>T<i/><sub>eff<sub/> = 1200–2500 K and with log(<i>ɡ<i/>) = 4.0. We computed atmospheric structures that self-consistently account for condensate cloud opacities based on microphysical properties. We present an algorithm based on control theory to help converge such self-consistent models. Synthetic atmosphere spectra were computed for each model to explore the observable impact of the cloud microphysics. We additionally explored the impact of choosing different nucleation species (TiO<sub>2<sub/> or SiO) and the effect of less efficient atmospheric mixing on these spectra.<i>Results<i/>. The new MSG cloudy grid using TiO<sub>2<sub/> nucleation shows spectra that are redder in the near-infrared compared to the currently known population of sub-stellar atmospheres. We find that the models with SiO nucleation and models with reduced mixing efficiency are less red in the near-infrared.<i>Conclusions<i/>. We present a new grid of MSG models for cloudy sub-stellar atmospheres that include cloud radiative feedback from microphysical clouds. The grid is unable to reproduce silicate features similar to the ones found in recent JWST observations and <i>Spitzer<i/> archival data. We thoroughly discuss further work that may better approximate the impact of convection in cloud-forming regions and steps that may help resolve the silicate cloud feature.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"2 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462360","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":"Simulating realistic self-interacting dark matter models including small and large-angle scattering","authors":"Cenanda Arido, Moritz S. Fischer, Mathias Garny","doi":"10.1051/0004-6361/202452551","DOIUrl":"https://doi.org/10.1051/0004-6361/202452551","url":null,"abstract":"<i>Context.<i/> Dark matter (DM) self-interactions alter matter distribution on galactic scales and alleviate tensions with observations. A feature of the self-interaction cross section is its angular dependence, which influences offsets between galaxies and DM halos in merging galaxy clusters. While algorithms for modelling mostly forward-dominated or mostly large-angle scatterings exist, incorporating realistic angular dependencies within <i>N<i/>-body simulations remains challenging.<i>Aims.<i/> To efficiently simulate models with a realistic angle dependence, such as light mediator models, we developed, validated, and applied a novel method.<i>Methods.<i/> We combined existing approaches to describe small- and large-angle scattering regimes within a hybrid scheme. Below a critical angle, the scheme uses the effective description of small-angle scattering via a drag force combined with transverse momentum diffusion, while above the angle, it samples the dependence explicitly.<i>Results.<i/> We first verified the scheme using a test set-up with known analytical solutions, and we checked that our results are insensitive to the choice of the critical angle within an expected range. Next, we demonstrated that our scheme speeds up the computations by multiple orders of magnitude for realistic light mediator models. Finally, we applied the method to galaxy cluster mergers. We discuss the sensitivity of the offset between galaxies and DM to the angle dependence of the cross section. Our scheme ensures accurate offsets for mediator mass <i>m<i/><sub><i>ϕ<i/><sub/> and DM mass <i>m<i/><sub><i>χ<i/><sub/> within the range 0.1<i>v<i/>/<i>c<i/> ≲ <i>m<i/><sub><i>ϕ<i/><sub/>/<i>m<i/><sub><i>χ<i/><sub/> ≲ <i>v<i/>/<i>c<i/>, while for larger (smaller) mass ratios, the offsets obtained for isotropic (forward-dominated) self-scattering are approached. Here, <i>v<i/> is the typical velocity scale. Equivalently, the upper condition can be expressed as for the ratio of the total and momentum transfer cross sections, with the ratio being 1 (∞) in the isotropic (forward-dominated) limits.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"50 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462427","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":"A failed wind candidate in NGC 3783 from the 2001 campaign with Chandra/HETGS","authors":"Chen Li, Jelle S. Kaastra, Liyi Gu, Daniele Rogantini, Anna Juráňová, Missagh Mehdipour, Jelle de Plaa","doi":"10.1051/0004-6361/202452911","DOIUrl":"https://doi.org/10.1051/0004-6361/202452911","url":null,"abstract":"We reanalyse the <i>Chandra<i/>/HETGS observations of NGC 3783 from the campaign in the year 2001 and identify significant spectral variations in the Fe unresolved transition array (UTA) over timescales of weeks to months. These changes correlate with a 1.4− to two-fold increase in the ionising continuum and exceed 10<i>σ<i/> significance. The variations primarily originate from a low-ionisation state (log <i>ξ<i/> = 1.65) component of the warm absorber. Time-dependent photoionisation modelling confirmed the sensitivity of this low-ionisation component to continuum variations within the Fe UTA band. Local fitting indicated a lower density limit of > 10<sup>12.3<sup/> m<sup>−3<sup/> at a 3<i>σ<i/> statistical uncertainty, with the component located within 0.27 pc. Our findings suggest that this low-ionisation component is a potential failed wind candidate.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"81 1 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462428","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":"Cosmic voids and the kinetic analysis","authors":"V. G. Gurzadyan, N. N. Fimin, V. M. Chechetkin","doi":"10.1051/0004-6361/202553679","DOIUrl":"https://doi.org/10.1051/0004-6361/202553679","url":null,"abstract":"The formation of cosmic structures in the late Universe was considered using the Vlasov kinetic approach. The crucial point is the use of the gravitational potential with repulsive term of the cosmological constant, which provides a solution to the Hubble tension, that is, the Hubble parameter for the late Universe has to differ from its global cosmological value. This also provides a mechanism of formation of stationary semi-periodic gravitating structures of voids and walls, so that the cosmological constant has the role of the scaling. It can therefore be compared with the observational data for given regions. The considered mechanism of the structure formation in the late cosmological epoch then succeeds the epoch described by the evolution of primordial density fluctuations.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"16 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462361","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":"Hanging on the cliff: Extreme mass ratio inspiral formation with local two-body relaxation and post-Newtonian dynamics","authors":"Davide Mancieri, Luca Broggi, Matteo Bonetti, Alberto Sesana","doi":"10.1051/0004-6361/202452306","DOIUrl":"https://doi.org/10.1051/0004-6361/202452306","url":null,"abstract":"Extreme mass ratio inspirals (EMRIs) are anticipated to be primary gravitational wave sources for the Laser Interferometer Space Antenna (LISA). They form in dense nuclear clusters when a compact object is captured by the central massive black holes (MBHs) as a consequence of the frequent two-body interactions occurring between orbiting objects. The physics of this process is complex and requires detailed statistical modelling of a multi-body relativistic system. We present a novel Monte Carlo approach to evolving the post-Newtonian (PN) equations of motion of a compact object orbiting an MBH. The approach accounts for the effects of two-body relaxation locally on the fly, without leveraging on the common approximation of orbit-averaging. We applied our method to study the function <i>S<i/>(<i>a<i/><sub>0<sub/>), describing the fraction of EMRI to total captures (including EMRIs and direct plunges, DPs) as a function of the initial semi-major axis <i>a<i/><sub>0<sub/> for compact objects orbiting central MBHs with <i>M<i/><sub>•<sub/> ∈ [10<sup>4<sup/> M<sub>⊙<sub/>, 4 × 10<sup>6<sup/> M<sub>⊙<sub/>]. The past two decades have consolidated a picture in which <i>S<i/>(<i>a<i/><sub>0<sub/>)→0 at large initial semi-major axes, with a sharp transition from EMRIs to DPs occurring around a critical scale <i>a<i/><sub>c<sub/>. A recent study challenges this notion for low-mass MBHs, finding EMRIs forming at <i>a<i/> ≫ <i>a<i/><sub>c<sub/>, which were called ‘cliffhangers’. Our simulations confirm the existence of cliffhanger EMRIs, which we find to be more common then previously inferred. Cliffhangers start to appear for <i>M<i/><sub>•<sub/> ≲ 3 × 10<sup>5<sup/> M<sub>⊙<sub/> and can account for up to 55% of the overall EMRIs forming at those masses. We find <i>S<i/>(<i>a<i/><sub>0<sub/>)≫0 for <i>a<i/> ≫ <i>a<i/><sub>c<sub/>, reaching values as high as 0.6 for <i>M<i/><sub>•<sub/> = 10<sup>4<sup/> M<sub>⊙<sub/>, much higher than previously found. We test how these results are influenced by different assumptions on the dynamics used to evolve the system and treatment of two-body relaxation. We find that the PN description of the system greatly enhances the number of EMRIs by shifting <i>a<i/><sub>c<sub/> to larger values at all MBH masses. Conversely, the local treatment of relaxation has a mass-dependent impact, significantly boosting the number of cliffhangers at low MBH masses compared to an orbit-averaged treatment. These findings highlight the shortcomings of standard approximations used in the EMRI literature and the importance of carefully modelling the (relativistic) dynamics of these systems. The emerging picture is more complex than previously thought, and should be considered in future estimates of rates and properties of EMRIs detectable by LISA.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"15 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462430","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":"Constraints on the properties of macroscopic transport in the Sun from combined lithium and beryllium depletion","authors":"G. Buldgen, A. Noels, A. M. Amarsi, D. Nandal, C. Pezzotti, R. Scuflaire, M. Deal, N. Grevesse","doi":"10.1051/0004-6361/202452918","DOIUrl":"https://doi.org/10.1051/0004-6361/202452918","url":null,"abstract":"<i>Context.<i/> The Sun is a privileged laboratory of stellar evolution, thanks to the quality and complementary nature of available constraints. Using these observations, we are able to draw a detailed picture of its internal structure and dynamics, which forms the basis of the successes of solar modelling. Amongst such observations, constraints on the depletion of lithium and beryllium are key tracers of the required efficiency and extent of macroscopic mixing just below the solar convective envelope. Thanks to revised determinations of these abundances, we may use them in conjunction with other existing spectroscopic and helioseismic constraints to study in detail the properties of macroscopic transport.<i>Aims.<i/> We aim to constrain the efficiency of macroscopic transport at the base of the solar convective zone (BCZ) and determining the compatibility of the observations with a suggested candidate linked with the transport of angular momentum in the solar radiative interior.<i>Methods.<i/> We use recent spectroscopic observations of lithium and beryllium abundance and include them in solar evolutionary model calibrations. We test the agreement of such models in terms of position of the convective envelope, helium mass fraction in the convective zone, sound speed profile inversions, and neutrino fluxes.<i>Results.<i/>We constrain the required efficiency and extent of the macroscopic mixing at the base of the BCZ, finding that a power-law density with an index, <i>n<i/>, between 3 and 6 would reproduce the data, with efficiencies at the BCZ of about 6000 cm<sup>2<sup/>/s, depending on the value of <i>n<i/>. We also confirm that macroscopic mixing worsens the agreement with neutrino fluxes and that the current implementations of the magnetic Tayler instability are unable to explain the observations.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"127 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143462353","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}