The interaction of core-collapse supernova ejecta with a stellar companion

The progenitors of many core-collapse supernovae (CCSNe) are expected to be in binary systems. By performing a series of three-dimensional hydrodynamical simulations, we investigate how CCSN explosions affect their binary companion. We find that the amount of removed stellar mass, the resulting impact velocity, and the chemical contamination of the companion that results from the impact of the SN ejecta, strongly increases with decreasing binary separation and increasing explosion energy. Also, it is foud that the impact effects of CCSN ejecta on the structure of main-sequence (MS) companions, and thus their long term post-explosion evolution, is in general not be dramatic.Comment: 5 pages, 3 figures, poster contribution: IAU Symposium 346 "High Mass X-ray Binaries: illuminating the passage from massive binaries to merging compact objects", Vienna, Austria, 27-31 August 2018. arXiv admin note: substantial text overlap with arXiv:1509.0363

The interaction of core-collapse supernova ejecta with a companion star

The progenitors of many CCSNe are expected to be in binary systems. After the SN explosion, the companion may suffer from mass stripping and be shock heated as a result of the impact of the SN ejecta. If the binary system is disrupted, the companion is ejected as a runaway and hypervelocity star. By performing a series of 3D hydrodynamical simulations of the collision of SN ejecta with the companion star, we investigate how CCSN explosions affect their companions. We use the BEC code to construct the detailed companion structure at the time of SN explosion. The impact of the SN blast wave on the companion is followed by means of 3D SPH simulations using the Stellar GADGET code. For main-sequence (MS) companions, we find that the amount of removed mass, impact velocity, and chemical contamination of the companion that results from the impact of the SN ejecta, strongly increases with decreasing binary separation and increasing explosion energy. Their relationship can be approximately fitted by power laws, which is consistent with the results obtained from impact simulations of SNe~Ia. However, we find that the impact velocity is sensitive to the momentum profile of the outer SN ejecta and, in fact, may decrease with increasing ejecta mass, depending on the modeling of the ejecta. Because most companions to Ib/c CCSNe are in their MS phase at the moment of the explosion, combined with the strongly decaying impact effects with increasing binary separation, we argue that the majority of these SNe lead to inefficient mass stripping and shock heating of the companion star following the impact of the ejecta. Our simulations show that the impact effects of Ib/c SN ejecta on the structure of MS companions, and thus their long-term post-explosion evolution, is in general not dramatic. We find that at most 10% of their mass is lost, and their resulting impact velocities are less than 100 km/s.Comment: Accepted for publication in Astronomy and Astrophysics, some minor typographical errors are fixed, the affiliation of second author is correcte

Can Neutron Star Mergers Alone Explain the r-process Enrichment of the Milky Way?

© 2023. The Author(s). Published by the American Astronomical Society. This is an open access article under the terms of the Creative Commons Attribution License, https://creativecommons.org/licenses/by/4.0/Comparing Galactic chemical evolution models to the observed elemental abundances in the Milky Way, we show that neutron star mergers can be a leading r-process site only if at low metallicities such mergers have very short delay times and significant ejecta masses that are facilitated by the masses of the compact objects. Namely, black hole–neutron star mergers, depending on the black hole spins, can play an important role in the early chemical enrichment of the Milky Way. We also show that none of the binary population synthesis models used in this Letter, i.e., COMPAS, StarTrack, Brussels, ComBinE, and BPASS, can currently reproduce the elemental abundance observations. The predictions are problematic not only for neutron star mergers, but also for Type Ia supernovae, which may point to shortcomings in binary evolution models.Peer reviewe

Ein Mikroventil und ein Verfahren zur Herstellung desselben

Ein Mikroventil weist einen Ventilsitz mit einer Ventiloeffnung und eine Ventilklappe zum Verschliessen der Ventiloeffnung des Mikroventils mit einem Abdeckabschnitt der Ventilklappe auf. In einem geschlossenen Zustand des Mikroventils befindet sich der Abdeckabschnitt der Ventilklappe in einer Ventilsitzebene. Die Ventilklappe ist in einer Schicht einstueckig gebildet wobei die Schicht derart eingespannt ist dass zumindest ein Teil der Schicht in dem geschlossenen Zustand aus der Ventilsitzebene ausgelenkt ist und die Ventilklappe auf den Ventilsitz gedrueckt wird

The interaction of core-collapse supernova ejecta with a companion star

Context. The progenitors of many core-collapse supernovae (CCSNe) are expected to be in binary systems. After the SN explosion in a binary, the companion star may suffer from mass stripping and be shock heated as a result of the impact of the SN ejecta. If the binary system is disrupted by the SN explosion, the companion star is ejected as a runaway star, and in some cases as a hypervelocity star. Aims. By performing a series of three-dimensional (3D) hydrodynamical simulations of the collision of SN ejecta with the companion star, we investigate how CCSN explosions affect their binary companion. Methods. We use the BEC stellar evolution code to construct the detailed companion structure at the moment of SN explosion. The impact of the SN blast wave on the companion star is followed by means of 3D smoothed particle hydrodynamics (SPH) simulations using the STELLAR GADGET code. Results. For main-sequence (MS) companion stars, we find that the amount of removed stellar mass, the resulting impact velocity, and the chemical contamination of the companion that results from the impact of the SN ejecta strongly increases with decreasing binary separation and increasing explosion energy. Their relationship can be approximately fitted by power laws, which is consistent with the results obtained from impact simulations of Type Ia SNe. However, we find that the impact velocity is sensitive to the momentum profile of the outer SN ejecta and, in fact, may decrease with increasing ejecta mass, depending on the modeling of the ejecta. Because most companion stars to Type Ib/c CCSNe are in their MS phase at the moment of the explosion, combined with the strongly decaying impact effects with increasing binary separation, we argue that the majority of these SNe lead to inefficient mass stripping and shock heating of the companion star following the impact of the ejecta. Conclusions. Our simulations show that the impact effects of Type Ib/c SN ejecta on the structure of MS companion stars, and thus their long-term post-explosion evolution, is in general not dramatic. We find that at most 10% of their mass is lost and their resulting impact velocities are less than 100 km s-1

Packaging of bio-MEMS: strategies, technologies and applications

International audienceBiomicroelectromechanical systems (bio-MEMS) are MEMS which are designed for medical or biological applications. As with other MEMS, bio-MEMS frequently, have to be packaged to provide an interface to the macroscale world of the user. Bio-MEMS can be roughly divided in two groups. Bio-MEMS can be pure technical systems applied in a biological environment or technical systems which integrate biological materials as one functional component of the system. In both cases, the materials which have intimate contact to biological matter have to be biocompatible to avoid unintentional effects on the biological substances, which in case of medical implants, could harm the patient. In the case of biosensors, the use of nonbiocompatible materials could interfere with the biological subcomponents which would affect the sensor's performance. Bio-MEMS containing biological subcomponents require the use of “biocompatible” technologies for assembly and packaging; e.g., high temperatures occurring, for instance, during thermosonic wire bonding and other thermobonding processes would denature the bioaffinity layers on biosensor chips. This means that the use of selected or alternative packaging and assembly methods, or new strategies, is necessary for a widerange of bio-MEMSapplications. This paper provides an overview of some of the strategies, technologies, and applications in the field of bio-MEMS packaging. It includes the following: 1) strategies for the partitioning of subsystems with integrated microsystems for (bio)chemical analysis/synthesis; 2) methods for microassembly of bio-MEMS; 3) technologies for bonding of polymer bio-MEMS components; 4) packaging of miniature medical devices; 5) packaging of biosensors for in vitro applications; 6) packaging of micropumps as a bio-MEMS component. The applications discussed are derived from different fields to demonstrate the plethora of bio-MEMS considerations. In commercial production, packaging is possibly the major cost factor of bio-MEMS-based products, and its development requires special attention