Astronomy & Astrophysics最新文献

{"title":"Exploring fluorine chemical evolution in the Galactic disk: The open cluster perspective","authors":"Shilpa Bijavara Seshashayana, H. Jonsson, V. d'orazi, N. Sanna, G. Andreuzzi, Govind Nandakumar, Angela Bragaglia, D. Romano, E. Spitoni","doi":"10.1051/0004-6361/202451056","DOIUrl":"https://doi.org/10.1051/0004-6361/202451056","url":null,"abstract":"Open clusters are ideal tools for tracing the abundances of different elements because their stars are expected to have the same age, distance, and metallicity. Therefore, they serve as powerful tracers for investigating the cosmic origins of elements. This paper expands on a recent study by us, in which the element fluorine was studied in seven open clusters; here we add six open clusters and eight field stars. The primary objective is to determine the abundance of fluorine (F) to gain insight into its production and evolution. The magnesium (Mg) abundances were derived to categorize the field stars into high and low alpha disk populations. Additionally, cerium (Ce) abundances were determined to better understand the interplay between F and s-process elements. Our goal is to analyze the trend of F abundances across the Galactic disk based on metallicity and age. By comparing observational data with Galactic chemical evolution models, the origin of F can be better understood. The spectra were obtained from the high-resolution near-infrared GIANO-B instrument at the Telescopio Nazionale Galileo (TNG). For the derivation of the stellar parameters and abundances, the Python version of Spectroscopy Made Easy ( PySME ) was used. OH, CN, and CO molecular lines and band heads along with Fe I lines were used to determine the stellar parameters in the H-band region. Two HF lines in the K band ($ 2.28, and 2.33 mu m), three K-band Mg I lines ($ 2.10, 2.11, and 2.15 mu m), and two Ce II lines in the H band ($ 1.66, and 1.71 mu m) were used to derive the abundances of F, Mg, and Ce, respectively. F, Mg, and Ce abundances were derived for 14 stars from 6 OCs, as well as for 8 field stars. The F and Ce abundances were investigated as a function of metallicity, age, and galactocentric distance. We also compared our findings with different Galactic chemical evolution models. Our results indicate that asymptotic giant branch stars and massive stars, including a subset of fast rotators (whose rotation speed likely increases as metallicity decreases), are necessary to explain the cosmic origin of F. This finding is consistent with and, with the large sample size, reinforces the conclusion of our previous study.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":" 112","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141833685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling the birthplaces of NGC 2070's massive stars, tracked with MUSE and revealed with JWST","authors":"N. C. L. F. A. Potsdam, Georg-August-Universitat Gottingen","doi":"10.1051/0004-6361/202347528","DOIUrl":"https://doi.org/10.1051/0004-6361/202347528","url":null,"abstract":"The formation of massive O-type stars cannot be simply explained as a scaled-up version of the accretion mechanisms observed in lower-mass stars. Understanding these processes necessitates systematic studies of their early stages, which are challenging to identify. Forming massive stars remain embedded in their dense nursery clouds, and IR instruments with high spatial resolution capabilities are needed to better observe them. Despite these challenges, MUSE optical observations of the massive cluster NGC 2070 successfully detected potential star-forming regions through spatially resolved electron density maps. To further explore these regions, the James Webb Space Telescope (JWST) utilized its NIRCam and MIRI instruments to penetrate optically obscured areas. This study examines two specific regions in the southeast part of the NGC 2070 MUSE density map, where tracks of highly dense point sources were identified. NIRCam, partially overlapped with MIRI, resolved these MUSE findings, revealing a procession of stellar point sources in the projected images. The detections are associated with elongated clouds, suggesting greater proper motions compared to the surrounding interstellar medium. These findings may indicate the presence of runaway candidates in the early stages of their evolution that are following common escape routes. This would support the notion that dynamical ejection is an efficient mechanism for the formation of massive runaway stars during early stages and likely plays a significant role in the origin of O-type field stars. However, additional data are required to confirm this scenario and rule out other ionizing feedback mechanisms, such as those observed in the formation of pillar-like structures around HII regions in the Milky Way. MUSE electron density mapping effectively captures the complexity of NGC 2070's interstellar medium and highlights targets for subsequent spectroscopic follow-ups, as demonstrated by the JWST data in the two fields studied.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":" 91","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141833794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The MeerKAT Fornax Survey. III. Ram-pressure stripping of the tidally interacting galaxy NGC 1427A in the Fornax cluster","authors":"P. Serra, T. Oosterloo, P. Kamphuis, G. Józsa, W. D. de Blok, G.L. Bryan, J. V. van Gorkom, E. Iodice, D. Kleiner, A. Loni, S. I. Loubser, F. Maccagni, D. Molnar, R. Peletier, D. J. Pisano, M. Ramatsoku, M.W.L. Smith, M. Verheijen, N. Zabel","doi":"10.1051/0004-6361/202450114","DOIUrl":"https://doi.org/10.1051/0004-6361/202450114","url":null,"abstract":"We present MeerKAT Fornax Survey observations of NGC 1427A, a blue irregular galaxy with a stellar mass of $ located near the centre of the Fornax galaxy cluster. Thanks to the excellent resolution (1 to 6 kpc spatially, 1.4 in velocity) and column density sensitivity ($ $ to $ $ cm$^ $ depending on resolution), our data deliver new insights on the long-debated interaction of this galaxy with the cluster environment. We confirm the presence of a broad, one-sided, starless tail stretching from the outer regions of the stellar body and pointing away from the cluster centre. We find the tail to have 50 more and to be 3 times longer (70 kpc) than in previous observations. In fact, we detect scattered clouds out to 300 kpc from the galaxy in the direction of the tail --- possibly the most ancient remnant of the passage of NGC 1427A through the intracluster medium of Fornax. Both the velocity gradient along the tail and the peculiar kinematics of in the outer region of the stellar body are consistent with the effect of ram pressure given the line-of-sight motion of the galaxy within the cluster. However, several properties cannot be explained solely by ram pressure and suggest an ongoing tidal interaction. This includes: the close match between dense and stars within the disturbed stellar body; the abundant kinematically anomalous and the inversion of the velocity gradient near the base of the tail. We rule out an interaction with the cluster tidal field, and conclude that NGC 1427A is the result of a high-speed galaxy encounter or of a merger started at least 300 Myr ago, where ram pressure shapes the distribution and kinematics of the in the perturbed outer stellar body and in the tidal tails.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"112 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141834378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"VVVX survey dusts off a new intermediate-age star cluster in the Milky Way disk","authors":"E. R. Garro, D. Minniti, J. Alonso-Garc'ia, J. G. Fern'andez-Trincado, M. G'omez, T. Palma, R. Saito, C. Obasi","doi":"10.1051/0004-6361/202450870","DOIUrl":"https://doi.org/10.1051/0004-6361/202450870","url":null,"abstract":"In the last decade, many new star clusters have been discovered in heavily obscured regions of the Milky Way bulge and disk. Our primary long-term objective is to seek out additional star clusters in the poorly studied regions of the Milky Way, where detections pose significant challenges. The aim of this pursuit is to finalize the Milky Way's globular and open cluster system census and to gain a comprehensive understanding of both the formation and evolution of these systems and our Galaxy as a whole. We report the discovery of a new star cluster, named Garro 03. We investigated this new target using a combination of near-infrared and optical databases. We employed the VISTA Variables in the Via Láctea Survey and Two Micron All Sky Survey data in the near-infrared, and the Gaia Data Release 3 and the DECam Plane Survey datasets in the optical passband. We constructed density maps and vector proper motion diagrams in order to highlight our target. We performed a photometrical analysis in order to derive its main physical parameters. Garro 03 is located at equatorial coordinates RA = 14:01:29.3 and Dec = $-$65:30:57.0. From our photometric analysis we find that this cluster is not heavily affected by extinction with $A_ Ks 0.04$ mag and $A_G = 1.54 0.02$ mag. It is located at heliocentric distance of $14.1 kpc, which places Garro 03 at $10.6$ kpc from the Galactic centre and Z = $-0.89$ kpc below the Galactic plane. We also calculated the mean cluster proper motion of ($ alpha ast delta 0.27$) mas $. We derived an age of 3 Gyr and metallicity Fe/H 0.2$ by the isochrone-fitting method, employing the PARSEC models. The total luminosity was derived in the $K_s$ and V bands, finding Ks 1.10$ mag and $M_V =-4.06$ mag. Finally, the core and tidal radii were measured constructing the Garro 03 radial density profile and fitting the King model. We obtained $r_c = 3.07 0.98$ pc and $r_t = 19.36 15.96$ pc, respectively. We photometrically confirm the cluster nature for Garro 03, located in the Galactic disk. It is a distant, low-luminosity, metal-rich star cluster of intermediate age. We also searched for possible signatures (streams or bridges) between Garro 03 and Garro 01, but we exclude a companionship with the present analysis. We need spectroscopic data to classify it as an old open cluster or a young globular cluster, and to understand its origin","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141834736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From traffic jams to roadblocks: The outer regions of TW Hya with ALMA Band 8","authors":"S. Das, N. Kurtovic, M. Flock","doi":"10.1051/0004-6361/202450278","DOIUrl":"https://doi.org/10.1051/0004-6361/202450278","url":null,"abstract":"Current ALMA surveys often underestimate protoplanetary disk sizes as many disks have extended low surface-brightness regions that fall below ALMA's detection limits. To effectively capture faint millimeter continuum emission in these outer regions, increased sensitivity is required. In order to gain insights on the connection between disk structure and planet formation, we aim to uncover continuum emission in the outer regions of the disk around TW Hya. Additionally, we aim to investigate the evolution of this disk by studying its dust properties. We present Atacama Large Millimeter Array (ALMA) observations of TW Hya at 0.65 mm with sim 0.5 arcsecond angular resolution, together with high angular resolution archival observations at 0.87 mm, 1.3 mm, 2.1 mm and 3.1 mm. We constrain the outer disk emission with both image-plane retrieval, and visibility-plane modeling with non-parametric and parametric fitting tools. Our results confirm emission in the outer disk regions of TW Hya (60 au leq R leq 110 au) at 0.65 mm, 0.87 mm and 1.3 mm. With image-plane retrieval we resolve the new continuum gap and ring, namely D79 and B86, at 0.87 mm and 1.3 mm. With visibility-plane modeling we also detect this substructure at 0.65 mm in the form of a quasi-constant emission at the 1sigma level Furthermore, it has a high spectral index of 3.7, which may indicate dust grain sizes ll 1 mm. It may be a dust trap or a traffic jam, that has a flux density of sim 60 mJy and a mass (1.59 $M_ that accounts for up to 2 of the dust disk at 0.65 mm. We confirm the existence of a faint ring in the outer regions of TW Hya at multiple millimeter wavelengths. With visibility-plane modeling, we are able to set constrains that are 3 times better than the resolution of our Band 8 observations.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"39 S173","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141835451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extended gamma-ray emission from particle escape in pulsar wind nebulae. Application to HESS J1809-193 and HESS J1825-137","authors":"Pierrick Martin, Louis de Guillebon, Eliot Collard, Ines Mertz, L. Mohrmann, G. Principe, M. Lemoine-Goumard, A. Marcowith, R. Terrier, Miroslav Filipovi'c","doi":"10.1051/0004-6361/202450254","DOIUrl":"https://doi.org/10.1051/0004-6361/202450254","url":null,"abstract":"There is growing evidence from gamma-ray observations at high and very high energies that particle escape is a key aspect shaping the morphological properties of pulsar wind nebulae (PWNe) at various evolutionary stages. We aim to provide a simple model for the gamma-ray emission from these objects including the transport of particles across the different components of the system. We applied it to sources HESS J1809$-$193 and HESS J1825$-$137. We developed a multi-zone framework applicable to dynamically young PWNe, taking into account the diffusive escape of relativistic electron-positron pairs out of the nebula into the parent supernova remnant (SNR) and their confinement downstream of the magnetic barrier of the forward shock until an eventual release into the surrounding interstellar medium (ISM). For a wide range of turbulence properties in the nebula, the GeV-TeV inverse-Compton radiation from pairs that escaped into the remnant can be a significant if not dominant contribution to the emission from the system. It may dominate the pion-decay radiation from cosmic rays accelerated at the forward shock and advected downstream of it. In the TeV-PeV range, the contribution from particles escaped into the ISM can exceed by far that of the SNR+PWN components. Applied to HESS J1809$-$193 and HESS J1825$-$137, we found that spatially extended GeV-TeV emission components can be accounted for mostly from particles escaped into the ISM, while morphologically more compact components above $50-100$ are ascribed to the PWNe. In these two cases, the model suggests high turbulence in the nebula and a forward shock accelerating cosmic rays up to $ at most. The model provides the temporal and spectral properties of the flux of particles originally energized by the pulsar wind and ultimately released in the ISM. It can be used to constrain the transport of particles in the vicinity of pulsar-PWN-SNR systems from broadband gamma-ray observations, or in studies of the contribution of pulsar-related systems to the local positron flux.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"36 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141835657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The neutral gas phase nearest to supermassive black holes. A massive neutral-atom- and molecule-rich broad line region in an active galactic nucleus","authors":"Wing-Fai Thi, Pantelis Papadopoulos","doi":"10.1051/0004-6361/202449905","DOIUrl":"https://doi.org/10.1051/0004-6361/202449905","url":null,"abstract":"Broad line regions (BLRs) are known to contain gravitationally bound gas within a\u0000 r$ $(few) times ($10^2$-$10^3$) Schwarszchild radii ($ S $) near supermassive black holes\u0000 (SMBHs) in active galactic nuclei (AGNs). Photo-ionized by a strong non-stellar AGN continuum, this gas emits\u0000 luminous ultraviolet/optical/near-infrared lines from ionized hydrogen (and other multi-ionized atoms) that have the widest velocity profiles observed in galaxies, uniquely indicating the deep gravitational wells of SMBHs. Nearly all BLR studies focus on its ionized gas phase (hereafter BLR$^ $), with typical masses of\u0000 only $ $(few) times (10-100), $ odot $, despite strong indications\u0000 of neutral BLR gas reservoirs (hereafter, BLR0) with $ BLR^ odot We used the photoionization code CLOUDY with its chemistry augmented using three-body reactions, to explore 1D models of dustless BLRs,\u0000 focusing on the BLR0 conditions and the abundances of its most prevalent neutral atoms and molecules. A (neutral-atom-) and molecule-rich BLR0 gas phase is found to be underlying the BLR$^ $. The latter \u0000 occupies only a thin outer layer of AGN-irradiated gas column densities, while the former contains the bulk of the BLR gas mass. Atomic carbon and oxygen as well as the CO molecule can reach substantial abundances in\u0000 the BLR0, while their lines at infrared (IR) and submillimeter (submm) wavelengths can yield new probes of the\u0000 BLR physical conditions and dynamics, unhindered by the dust absorption from outer AGN tori that\u0000 readily absorb the BLR$^ $ optical and far-ultraviolet (FUV) lines. We find that neutral-atom-rich and even molecule-rich gas can exist in the BLR0. The corresponding spectral lines from\u0000 neutral atoms and molecules promise a new spectral window of gas dynamics in the vicinity of SMBHs unhindered\u0000 by dust absorption. This may even offer the prospect of conducting novel tests of general relativity in strongly curved spacetime.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"13 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141835881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling the nature of two dwarf novae: CRTS J080846.2+313106 and V416 Dra","authors":"Arti Joshi, M'arcio Catelan, S. Scaringi, Axel D. Schwope, G. Anupama, Nikita Rawat, D. Sahu, Mridweeka Singh, R. Dastidar, Rama Venkata Subramanian, Srinivas M. Rao","doi":"10.1051/0004-6361/202348307","DOIUrl":"https://doi.org/10.1051/0004-6361/202348307","url":null,"abstract":"We present the analysis of optical photometric and spectroscopic observations of two non-magnetic cataclysmic variables, namely CRTS J080846.2+313106 and V416 Dra. We find CRTS J080846.2+313106 to vary with a period of 4.9116pm 0.0003 h, which was not found in earlier studies and which we provisionally suggest is the orbital period of the system. In both long-period systems, the observed dominant signal at the second harmonic of the orbital frequency and the orbital modulation during quiescence are suggestive of ellipsoidal variation from changing aspects of the secondary, with an additional contribution from the accretion stream or hotspot. However, during the outburst, the hotspot itself is overwhelmed by the increased brightness, which is possibly associated with the accretion disc. The mid-eclipse phase for V416 Dra occurs earlier and the width of the eclipse is greater during outbursts compared to quiescence, suggesting an increased accretion disc radius during outbursts. Furthermore, from our investigation of the accretion disc eclipse in V416 Dra, we find that a total disc eclipse is possible during quiescence, whereas the disc seems to be partially obscured during outbursts, which further signifies that the disc may grow in size as the outburst progresses. The optical spectra of CRTS J080846.2+313106 and V416 Dra are typical of dwarf novae during quiescence, and they both show a significant contribution from the M2-4V secondary. The light curve patterns, orbital periods, and spectra observed in the two systems look remarkably similar, and seem to resemble the characteristics of U Gem-type dwarf novae.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"80 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141835549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The evolution of accreting population III stars at 10^{-6} - 10^3 Ms yr^{-1}","authors":"D. Nandal, L. Zwick, D. Whalen, Lucio Mayer, S. Ekstrom, G. Meynet","doi":"10.1051/0004-6361/202449562","DOIUrl":"https://doi.org/10.1051/0004-6361/202449562","url":null,"abstract":"The first stars formed over five orders of magnitude in mass by accretion in primordial dark matter halos. We study the evolution of massive, very massive and supermassive primordial (Pop III) stars over nine orders of magnitude in accretion rate. We use the stellar evolution code GENEC to evolve accreting Pop III stars from 10$^ $ and study how these rates determine final masses. The stars are evolved until either the end central Si burning or they encounter the general relativistic instability (GRI). We also examine how metallicity affects the evolution of the star at one accretion rate. At rates below sim $2.5 $ the final mass of the star falls below that required for pair-instability supernovae. The minimum rate required to produce black holes with masses above 250 is $ $, well within the range of infall rates found in numerical simulations of halos that cool via H$_2$, $ $. At rates of $5 $ to $4 $, like those expected for halos cooling by both H$_2$ and Lyalpha , the star collapses after Si burning. At higher accretion rates the GRI triggers the collapse of the star during central H burning. Stars that grow at above these rates are cool red hypergiants with effective temperatures $log(T_ eff ) = 3.8$ and luminosities that can reach 10$^ At accretion rates of 100 - 1000 $ the gas encounters the general relativistic instability prior to the onset of central hydrogen burning and collapses to a black hole with a mass of sim 10$^6$ without ever having become a star. Our models corroborate previous studies of Pop III stellar evolution with and without hydrodynamics over separate, smaller ranges in accretion rate. They also reveal for the first time the critical transition rate in accretion above which catastrophic baryon collapse, like that which can occur during galaxy collisions in the high-redshift Universe, produces supermassive black holes via dark collapse.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141835900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Grids of stellar models with rotation. VIII. Models from 1.7 to 500 M⊙ at metallicity Z = 10-5","authors":"Yves Sibony, Kendall G. Shepherd, N. Yusof, Raphael Hirschi, Caitlan Chambers, Sophie Tsiatsiou, D. Nandal, Luca Sciarini, F. Moyano, J. B'etrisey, G. Buldgen, C. Georgy, S. Ekstrom, Patrick Eggenberger, G. Meynet","doi":"10.1051/0004-6361/202450180","DOIUrl":"https://doi.org/10.1051/0004-6361/202450180","url":null,"abstract":"Grids of stellar evolution models with rotation using the Geneva stellar evolution code ( Genec ) have been published for a wide range of metallicities. We introduce the last remaining grid of Genec models, with a metallicity of $Z=10^ $. We study the impact of this extremely metal-poor initial composition on various aspects of stellar evolution, and compare it to the results from previous grids at other metallicities. We provide electronic tables that can be used to interpolate between stellar evolution tracks and for population synthesis. Using the same physics as in the previous papers of this series, we computed a grid of stellar evolution models with Genec spanning masses between 1.7 and 500,$M_ with and without rotation, at a metallicity of Due to the extremely low metallicity of the models, mass-loss processes are negligible for all except the most massive stars. For most properties (such as evolutionary tracks in the Hertzsprung-Russell diagram, lifetimes, and final fates), the present models fit neatly between those previously computed at surrounding metallicities. However, specific to this metallicity is the very large production of primary nitrogen in moderately rotating stars, which is linked to the interplay between the hydrogen- and helium-burning regions. The stars in the present grid are interesting candidates as sources of nitrogen-enrichment in the early Universe. Indeed, they may have formed very early on from material previously enriched by the massive short-lived Population III stars, and as such constitute a very important piece in the puzzle that is the history of the Universe.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"30 47","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141835759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}