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9 Publications matching the given criteria: (Clear all filters)
Published year: 20239
The young massive SMC cluster NGC 330 seen by MUSE. III. Stellar parameters and rotational velocities

Abstract

Not specified

Authors: J. Bodensteiner, H. Sana, P. L. Dufton, C. Wang, N. Langer, G. Banyard, L. Mahy, A. de Koter, S. E. de Mink, C. J. Evans, Y. Götberg, V. Hénault-Brunet, L. R. Patrick, F. R. N. Schneider

Date Published: 1st Dec 2023

Publication Type: Journal

Clumping and X-rays in cooler B supergiant stars

Abstract

Not specified

Authors: M. Bernini-Peron, W. L. F. Marcolino, A. A. C. Sander, J. -C. Bouret, V. Ramachandran, J. Saling, F. R. N. Schneider, L. M. Oskinova, F. Najarro

Date Published: 1st Sep 2023

Publication Type: Journal

X-Shooting ULLYSES: Massive stars at low metallicity. I. Project description

Abstract (Expand)

Observations of individual massive stars, super-luminous supernovae, gamma-ray bursts, and gravitational wave events involving spectacular black hole mergers indicate that the low-metallicity Universe … is fundamentally different from our own Galaxy. Many transient phenomena will remain enigmatic until we achieve a firm understanding of the physics and evolution of massive stars at low metallicity (Z). The Hubble Space Telescope has devoted 500 orbits to observing ∼250 massive stars at low Z in the ultraviolet (UV) with the COS and STIS spectrographs under the ULLYSES programme. The complementary X-Shooting ULLYSES (XShootU) project provides an enhanced legacy value with high-quality optical and near-infrared spectra obtained with the wide-wavelength coverage X-shooter spectrograph at ESO’s Very Large Telescope. We present an overview of the XShootU project, showing that combining ULLYSES UV and XShootU optical spectra is critical for the uniform determination of stellar parameters such as effective temperature, surface gravity, luminosity, and abundances, as well as wind properties such as mass-loss rates as a function of Z. As uncertainties in stellar and wind parameters percolate into many adjacent areas of astrophysics, the data and modelling of the XShootU project is expected to be a game changer for our physical understanding of massive stars at low Z. To be able to confidently interpret James Webb Space Telescope spectra of the first stellar generations, the individual spectra of low-Z stars need to be understood, which is exactly where XShootU can deliver. Table B.1 and full Table B.2 are available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (ftp://130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/675/A154 Based on observations collected at the European Southern Observatory under ESO programme 106.211Z.001.

Authors: Jorick S. Vink, A. Mehner, P. A. Crowther, A. Fullerton, M. Garcia, F. Martins, N. Morrell, L. M. Oskinova, N. St-Louis, A. ud-Doula, A. A. C. Sander, H. Sana, J. -C. Bouret, B. Kubátová, P. Marchant, L. P. Martins, A. Wofford, J. Th. van Loon, O. Grace Telford, Y. Götberg, D. M. Bowman, C. Erba, V. M. Kalari, M. Abdul-Masih, T. Alkousa, F. Backs, C. L. Barbosa, S. R. Berlanas, M. Bernini-Peron, J. M. Bestenlehner, R. Blomme, J. Bodensteiner, S. A. Brands, C. J. Evans, A. David-Uraz, F. A. Driessen, K. Dsilva, S. Geen, V. M. A. Gómez-González, L. Grassitelli, W. -R. Hamann, C. Hawcroft, A. Herrero, E. R. Higgins, D. John Hillier, R. Ignace, A. G. Istrate, L. Kaper, N. D. Kee, C. Kehrig, Z. Keszthelyi, J. Klencki, A. de Koter, R. Kuiper, E. Laplace, C. J. K. Larkin, R. R. Lefever, C. Leitherer, D. J. Lennon, L. Mahy, J. Maíz Apellániz, G. Maravelias, W. Marcolino, A. F. McLeod, S. E. de Mink, F. Najarro, M. S. Oey, T. N. Parsons, D. Pauli, M. G. Pedersen, R. K. Prinja, V. Ramachandran, M. C. Ramírez-Tannus, G. N. Sabhahit, A. Schootemeijer, S. Reyero Serantes, T. Shenar, G. S. Stringfellow, N. Sudnik, F. Tramper, L. Wang

Date Published: 1st Jul 2023

Publication Type: Journal

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

Abstract

Not specified

Authors: Fabian R. N. Schneider, Philipp Podsiadlowski, Eva Laplace

Date Published: 15th Jun 2023

Publication Type: Journal

The contribution of binary star formation via core fragmentation on protostellar multiplicity

Abstract (Expand)

Context. Observations of young multiple star systems find a bimodal distribution in companion frequency and separation. The origin of these peaks has often been attributed to binary formation via core …been attributed to binary formation via core and disc fragmentation. However, theory and simulations suggest that young stellar systems that form via core fragmentation undergo significant orbital evolution. Aims. We investigate the influence of the environment on the formation and orbital evolution of multiple star systems, and how core fragmentation contributes to the formation of close (20 − 100 AU) binaries. We use multiple simulations of star formation in giant molecular clouds and compare them to the multiplicity statistics of the Perseus star-forming region. Methods. Simulations were run with the adaptive mesh refinement code RAMSES with sufficient resolution to resolve core fragmentation beyond 400 AU and dynamical evolution down to 16.6 AU, but without the possibility of resolving disc fragmentation. The evolution of the resulting stellar systems was followed over millions of years. Results. We find that star formation in lower gas density environments is more clustered; however, despite this, the fractions of systems that form via dynamical capture and core fragmentation are broadly consistent at ∼40% and ∼60%, respectively. In all gas density environments, we find that the typical scale at which systems form via core fragmentation is 10 3 − 3.5  AU. After formation, we find that systems that form via core fragmentation have slightly lower inspiral rates (∼10 −1.68  AU yr −1 measured over the first 10 000 yr) compared to dynamical capture (∼10 −1.32  AU yr −1 ). We then compared the simulation with the conditions most similar to the Perseus star-forming region to determine whether the observed bimodal distribution can be replicated. We find that it can be replicated, but it is sensitive to the evolutionary state of the simulation. Conclusions. Our results indicate that a significant number of low-mass close binaries with separations from 20 − 100 AU can be produced via core fragmentation or dynamical capture due to efficient inspiral, without the need for a further contribution from disc fragmentation.

Authors: Rajika L. Kuruwita, Troels Haugbølle

Date Published: 1st Jun 2023

Publication Type: Journal

Nucleosynthesis of Binary-stripped Stars

Abstract (Expand)

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 F and K being more significantly produced by binary-stripped stars than single stars. We find that the 12C/13C could be used as an indicator of the conservativeness of mass transfer, as 13C is preferentially ejected during mass transfer while 12C 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 that 44V and 52Mn are strong probes of the explosion model, while for binary-stripped stars it is 48Cr. Our findings highlight that binary-stripped stars are not equivalent to two single stars and that detailed stellar modeling is needed to predict their final nucleosynthetic yields.

Authors: R. Farmer, E. Laplace, Jing-ze Ma, S. E. de Mink, S. Justham

Date Published: 12th May 2023

Publication Type: Journal

Gravitational wave emission from dynamical stellar interactions

Abstract

Not specified

Authors: Javier Morán-Fraile, Fabian R. N. Schneider, Friedrich K. Röpke, Sebastian T. Ohlmann, Rüdiger Pakmor, Theodoros Soultanis, Andreas Bauswein

Date Published: 1st Apr 2023

Publication Type: Journal

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