Evolution and final fate of massive post-common-envelope binaries

Mergers of neutron stars (NSs) and black holes (BHs) are nowadays observed routinely thanks to gravitational-wave (GW) astronomy. In the isolated binary-evolution channel, a common-envelope (CE) phase of a red supergiant (RSG) and a compact object is crucial to sufficiently shrink the orbit and thereby enable a merger via GW emission. Here, we use the outcomes of two three-dimensional (3D) magneto-hydrodynamic CE simulations of an initially 10.0 solar-mass RSG with a 5.0 solar-mass BH and a 1.4 solar-mass NS, respectively, to explore the further evolution and final fate of the post-CE binaries. Notably, the 3D simulations reveal that the post-CE binaries are likely surrounded by circumbinary disks (CBDs), which contain substantial mass and angular momentum to influence the subsequent evolution. The binary systems in MESA modelling undergo another phase of mass transfer (MT) and we find that most donor stars do not explode in ultra-stripped supernovae (SNe), but rather in Type Ib/c SNe. The final orbits of our models with the BH companion are too wide, and NS kicks are actually required to sufficiently perturb the orbit and thus facilitate a merger via GW emission. Moreover, by exploring the influence of CBDs, we find that mass accretion from the disk widens the binary orbit, while CBD-binary resonant interactions can shrink the separation and increase the eccentricity depending on the disk mass and lifetime. Efficient resonant contractions may even enable NS/BH to merge with the remnant He stars before a second SN explosion, which may be observed as gamma-ray burst-like transients, luminous fast blue optical transients and Thorne-\.Zytkow objects. For the surviving post-CE binaries, the CBD-binary interactions may significantly increase the GW-induced double compact merger fraction. We conclude that accounting for CBD may be crucial to better understand observed GW mergers.Comment: 19 pages, 19 figures, 1 table. Submitted to A&A, comments welcom

Metadata standards and practical guidelines for specimen and DNA curation when building barcode reference libraries for aquatic life

DNA barcoding and metabarcoding is increasingly used to effectively and precisely assess and monitor biodiversity in aquatic ecosystems. As these methods rely on data availability and quality of barcode reference libraries, it is important to develop and follow best practices to ensure optimal quality and traceability of the metadata associated with the reference barcodes used for identification. Sufficient metadata, as well as vouchers, corresponding to each reference barcode must be available to ensure reliable barcode library curation and, thereby, provide trustworthy baselines for downstream molecular species identification. This document (1) specifies the data and metadata required to ensure the relevance, the accessibility and traceability of DNA barcodes and (2) specifies the recommendations for DNA harvesting and for the storage of both voucher specimens/samples and barcode data.info:eu-repo/semantics/publishedVersio

Bringing Stellar Evolution & Feedback Together: Summary of proposals from the Lorentz Center Workshop, 2022

Stars strongly impact their environment, and shape structures on all scales throughout the universe, in a process known as ``feedback''. Due to the complexity of both stellar evolution and the physics of larger astrophysical structures, there remain many unanswered questions about how feedback operates, and what we can learn about stars by studying their imprint on the wider universe. In this white paper, we summarize discussions from the Lorentz Center meeting `Bringing Stellar Evolution and Feedback Together' in April 2022, and identify key areas where further dialogue can bring about radical changes in how we view the relationship between stars and the universe they live in.Comment: Accepted to the Publications of the Astronomical Society of the Pacifi

Trends in the epidemiology of catheter-related bloodstream infections; towards a paradigm shift, Spain, 2007 to 2019

Altres ajuts: Departament de Salut. Generalitat de Catalunya ("Pla estratègic de recerca i innovació en salut (PERIS) 2019-2021"); Ministerio de Asuntos Económicos y Transformación Digital; Red Española de Investigación en Patología Infecciosa (REIPI).Background: Catheter-related bloodstream infections (CRBSI) are frequent healthcare-associated infections and an important cause of death. Aim: To analyse changes in CRBSI epidemiology observed by the Infection Control Catalan Programme (VINCat). Methods: A cohort study including all hospital-acquired CRBSI episodes diagnosed at 55 hospitals (2007-2019) in Catalonia, Spain, was prospectively conducted. CRBSI incidence rates were adjusted per 1,000patientdays. To assess the CRBSI rate trend per year, negative binomial models were used, with the number of events as the dependent variable, and the year as the main independent variable. From each model, the annual rate of CRBSI diagnosed per 1,000patientdays and the incidence rate ratio (IRR) with its 95% confidence intervals (CI) were reported. Results: During the study, 9,290 CRBSI episodes were diagnosed (mean annual incidence rate:0.20episodes/1,000patientdays). Patients' median age was 64.1years; 36.6% (3,403/9,290) were female. In total, 73.7% (n=6,845) of CRBSI occurred in non-intensive care unit (ICU) wards, 62.7% (n=5,822) were related to central venous catheter (CVC), 24.1% (n=2,236) to peripheral venous catheters (PVC) and 13.3% (n=1,232) to peripherally-inserted central venous catheters (PICVC). Incidence rate fell over the study period (IRR:0.94;95%CI:0.93-0.96), especially in the ICU (IRR:0.88;95%CI:0.87-0.89). As a whole, while episodes of CVC CRBSI fell significantly (IRR:0.88;95%CI:0.87-0.91), peripherally-inserted catheter CRBSI (PVC and PICVC) rose, especially in medical wards (IRR PICVC:1.08;95%CI:1.05-1.11; IRR PVC: 1.03; 95% 1.00-1.05). Conclusions: Over the study, CRBSIs associated with CVC and diagnosed in ICUs decreased while episodes in conventional wards involving peripherally-inserted catheters increased. Hospitals should implement preventive measures in conventional wards

Bimodal black-hole mass distribution and chirp masses of binary black-hole mergers

In binary black-hole mergers from isolated binary-star evolution, both black holes are from progenitor stars that have lost their hydrogen-rich envelopes by binary mass transfer. Envelope stripping is known to affect the pre-supernova core structures of such binary-stripped stars and thereby their final fates and compact remnant masses. In this paper, we show that binary-stripped stars give rise to a bimodal black-hole mass spectrum with characteristic black-hole masses of about $9\,\mathrm{M}_\odot$ and $16\,\mathrm{M}_\odot$ across a large range of metallicities. The bimodality is linked to carbon and neon burning becoming neutrino-dominated, which results in interior structures that are difficult to explode and likely lead to black hole formation. The characteristic black-hole masses from binary-stripped stars have corresponding features in the chirp-mass distribution of binary black-hole mergers: peaks at about $8$ and $14\,\mathrm{M}_\odot$, and a dearth in between these masses. Current gravitational-wave observations of binary black-hole mergers show evidence for a gap at $10\text{--}12\,\mathrm{M}_\odot$ and peaks at $8$ and $14\,\mathrm{M}_\odot$ in the chirp-mass distribution. These features are in agreement with our models of binary-stripped stars. In the future, they may be used to constrain the physics of late stellar evolution and supernova explosions, and may even help measure the cosmological expansion of the Universe.Comment: 20 pages (including appendix with tabulated data; main text: 8 pages), 6 figures; accepted for publication in ApJ Letter

Bimodal Black Hole Mass Distribution and Chirp Masses of Binary Black Hole Mergers

In binary black hole mergers from isolated binary-star evolution, both black holes are from progenitor stars that have lost their hydrogen-rich envelopes by binary mass transfer. Envelope stripping is known to affect the pre-supernova core structures of such binary-stripped stars and thereby their final fates and compact remnant masses. In this paper, we show that binary-stripped stars give rise to a bimodal black hole mass spectrum with characteristic black hole masses of about 9 M _⊙ and 16 M _⊙ across a large range of metallicities. The bimodality is linked to carbon and neon burning becoming neutrino dominated, which results in interior structures that are difficult to explode and likely lead to black hole formation. The characteristic black hole masses from binary-stripped stars have corresponding features in the chirp-mass distribution of binary black hole mergers: peaks at about 8 and 14 M _⊙ and a dearth in between these masses. Current gravitational-wave observations of binary black hole mergers show evidence for a gap at 10–12 M _⊙ and peaks at 8 and 14 M _⊙ in the chirp-mass distribution. These features are in agreement with our models of binary-stripped stars. In the future, they may be used to constrain the physics of late stellar evolution and supernova explosions and may even help measure the cosmological expansion of the universe

Nucleosynthesis of binary-stripped stars.

<p>The cosmic origin of the elements, the fundamental chemical building blocks of the Universe, is still uncertain. Binary interactions play a key role in the evolution of many massive stars, yet their impact on chemical yields is poorly understood. Using the MESA stellar evolution code we predict the chemical yields ejected in wind mass loss and the supernovae of single and binary-stripped stars. We do this with a large 162 isotope nuclear network at solar-metallicity. We find that binary-stripped stars are more effective producers of the elements than single stars, due to their increased mass loss and an increased chance to eject their envelopes during a supernova. This increased production by binaries varies across the periodic table, with \fluorine[] and \potassium[] being more significantly produced by binary-stripped stars than single stars. We find that the \carbon[12]/\carbon[13] could be used as an indicator of the conservativeness of mass transfer, as \carbon[13] is preferentially ejected during mass transfer while \carbon[12] is preferentially ejected during wind mass loss. We identify a number of gamma-ray emitting radioactive isotopes that may be used to help constrain progenitor and explosion models of core-collapse supernovae with next-generation gamma-ray detectors. For single stars we find \vanadium[44] and \manganese[52] are strong probes of the explosion model, while for binary-stripped stars it is \chromium[48]. Our findings highlight that binary-stripped stars are not equivalent to two single stars and that detailed stellar modelling is needed to predict their final nucleosynthetic yields.</p><p> </p><p>MESA version: 12115</p><p> </p><p>This dataset contains the inlists, output from MESA, scripts, and data tables used in this publication.</p><p> </p><p>The tables folder contains the chemical yields for all models, isotopes, and mass loss processes.</p><p> </p><p>Accepeted for publication in ApJ</p&gt

Possible regular phenomena in EXO 2030+375

In the last 10 yr, since its last giant outburst in 2006, regular X-ray outbursts (type I) were detected every periastron passage in the Be X-ray binary EXO 2030+375. Recently, however, it was reported that the source started to show a peculiar behavior: its X-ray flux decreased significantly and type I outbursts were missed in several cases. At the same time, the spin frequency of the neutron star, which had been increasing steadily since the end of the 2006 giant outburst, reached a plateau. Very recent observations indicate that the source is now starting to spin down. These observed phenomena have a striking similarity with those which took place 21 yr ago, just before the source displayed a sudden orbital phase shift of the outburst peak (1995). This historical event occurred at the time exactly between the two giant outbursts (1985 and 2006). These phenomena suggest the system to have an underlying periodicity of 10.5 yr between orbital phase shifts and/or giant outbursts. The suggested periodicity may reflect some long-period dynamics in the circumstellar disk of the Be star, due, e.g., to the Kozai-Lidov effect. A model generating such a periodic change of the Be disk, namely Kozai-Lidov oscillations in the Be disk, is discussed. If this behavior is really periodical, another phase shift of the X-ray outburst peak is predicted to occur around 2016 December

Bringing Stellar Evolution and Feedback Together:Summary of Proposals from the Lorentz Center Workshop

Stars strongly impact their environment, and shape structures on all scales throughout the universe, in a process known as “feedback.” Due to the complexity of both stellar evolution and the physics of larger astrophysical structures, there remain many unanswered questions about how feedback operates and what we can learn about stars by studying their imprint on the wider universe. In this white paper, we summarize discussions from the Lorentz Center meeting “Bringing Stellar Evolution and Feedback Together” in 2022 April and identify key areas where further dialog can bring about radical changes in how we view the relationship between stars and the universe they live in.</p