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

2018 ◽  
Vol 14 (S346) ◽  
pp. 55-58
Author(s):  
Zheng-Wei Liu ◽  
T. M. Tauris ◽  
F. K. Röpke ◽  
T. J. Moriya ◽  
M. Kruckow ◽  
...  
Keyword(s):  
Binary Systems ◽  
Main Sequence ◽  
Three Dimensional ◽  
Core Collapse ◽  
Chemical Contamination ◽  
Binary Separation ◽  
Hydrodynamical Simulations ◽  
Many Core ◽  
The Impact

AbstractThe 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, are in general not dramatic.

scholarly journals A systematic study of proto-neutron star convection in three-dimensional core-collapse supernova simulations

2020 ◽  
Vol 492 (4) ◽  
pp. 5764-5779 ◽  
Author(s):  
Hiroki Nagakura ◽  
Adam Burrows ◽  
David Radice ◽  
David Vartanyan
Keyword(s):  
Neutron Star ◽  
Systematic Study ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Core Collapse ◽  
Core Collapse Supernova ◽  
Tau Neutrinos ◽  
The Impact ◽  
Proto Neutron Star

ABSTRACT This paper presents the first systematic study of proto-neutron star (PNS) convection in three dimensions (3D) based on our latest numerical fornax models of core-collapse supernova (CCSN). We confirm that PNS convection commonly occurs, and then quantify the basic physical characteristics of the convection. By virtue of the large number of long-term models, the diversity of PNS convective behaviour emerges. We find that the vigour of PNS convection is not correlated with CCSN dynamics at large radii, but rather with the mass of PNS − heavier masses are associated with stronger PNS convection. We find that PNS convection boosts the luminosities of νμ, ντ, $\bar{\nu }_{\mu }$, and $\bar{\nu }_{\tau }$ neutrinos, while the impact on other species is complex due to a competition of factors. Finally, we assess the consequent impact on CCSN dynamics and the potential for PNS convection to generate pulsar magnetic fields.

scholarly journals Three-dimensional simulations of the interaction between the nova ejecta, accretion disk, and companion star

2018 ◽  
Vol 613 ◽  
pp. A8 ◽  
Author(s):  
Joana Figueira ◽  
Jordi José ◽  
Enrique García-Berro ◽  
Simon W. Campbell ◽  
Domingo García-Senz ◽  
...  
Keyword(s):  
Accretion Disk ◽  
White Dwarf ◽  
Binary Systems ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Potential Effect ◽  
Model Parameters ◽  
Chemical Contamination ◽  
Particle Hydrodynamics ◽  
The Impact

Context. Classical novae are thermonuclear explosions hosted by accreting white dwarfs in stellar binary systems. Material piles up on top of the white dwarf star under mildly degenerate conditions, driving a thermonuclear runaway. The energy released by the suite of nuclear processes operating at the envelope, mostly proton-capture reactions and β+-decays, heats the material up to peak temperatures ranging from 100 to 400 MK. In these events, about 10−3–10−7 M⊙, enriched in CNO and, sometimes, other intermediate-mass elements (e.g., Ne, Na, Mg, and Al) are ejected into the interstellar medium. Aims. To date, most of the efforts undertaken in the modeling of classical nova outbursts have focused on the early stages of the explosion and ejection, ignoring the interaction of the ejecta, first with the accretion disk orbiting the white dwarf and ultimately with the secondary star. Methods. A suite of 3D, smoothed-particle hydrodynamics (SPH) simulations of the interaction between the nova ejecta, accretion disk, and stellar companion were performed to fill this gap; these simulations were aimed at testing the influence of the model parameters—that is, the mass and velocity of the ejecta, mass and the geometry of the accretion disk—on the dynamical and chemical properties of the system. Results. We discuss the conditions that lead to the disruption of the accretion disk and to mass loss from the binary system. In addition, we discuss the likelihood of chemical contamination of the stellar secondary induced by the impact with the nova ejecta and its potential effect on the next nova cycle.

scholarly journals Long-term evolution of surviving companion stars of Type Iax supernovae

2020 ◽  
Vol 500 (1) ◽  
pp. 301-309
Author(s):  
Zheng-Wei Liu ◽  
Yaotian Zeng
Keyword(s):  
Stellar Evolution ◽  
Main Sequence ◽  
Three Dimensional ◽  
Late Time ◽  
One Dimensional ◽  
Term Evolution ◽  
Post Impact ◽  
Explosion Mechanism ◽  
Hydrodynamical Simulations

ABSTRACT The nature of the progenitors and explosion mechanism of Type Iax supernovae (SNe Iax) remain a mystery. The single-degenerate (SD) systems that involve the incomplete pure deflagration explosions of near-Chandrasekhar-mass white dwarfs (WDs) have recently been proposed for producing SNe Iax in which non-degenerate companions are expected to survive from SN explosions. In this work, we concentrate on the main-sequence (MS) donor SD progenitor systems. By mapping the computed companion models from three-dimensional hydrodynamical simulations of ejecta-companion interaction into a one-dimensional stellar evolution code mesa, we investigate the long-term appearance and observational signatures of surviving MS companions of SNe Iax by tracing their post-impact evolution. Depending on different MS companion models, it is found that the shocked surviving companion stars can significantly expand and evolve to be more luminous (5–$500\, L_{\odot }$) for a time-scale of 10–104 yr. Comparing with the late-time light curve of an observed SN Iax (SN 2005hk), it is suggested that surviving MS companions of SNe Iax would expect to be visible about 1000 d after the explosion when SN itself has been faded.

scholarly journals Guanxi, Trust, and Long-Term Orientation in Chinese Business Markets

2005 ◽  
Vol 13 (2) ◽  
pp. 28-56 ◽  
Author(s):  
Don Y. Lee ◽  
Philip L. Dawes
Keyword(s):  
Hong Kong ◽  
Interpersonal Relationships ◽  
Chinese Culture ◽  
Three Dimensional ◽  
Business Markets ◽  
Latent Construct ◽  
Chinese Business ◽  
The Government ◽  
The Impact

This research focuses on buying firms’ trust in a supplier's salesperson and posits that this type of trust is determined by characteristics of the salesperson, the interpersonal relationships between a salesperson and the buying firm's boundary personnel, and characteristics of personal interactions between these two parties. More important, the authors discuss the concept of interpersonal relationships in the context of Chinese culture and model it as a three-dimensional latent construct, which, in some literature, is called guanxi. A key aspect of this research is that the authors investigate the impact of each dimension of guanxi on salesperson trust separately. Moreover, the authors consider the buying firm's trust in the supplying firm and its long-term orientation toward the supplier the consequences of salesperson trust. To test the model, the authors use data collected from 128 buying organizations in Hong Kong. The sampled firms are from both the government and private sectors.

scholarly journals Heart of darkness: the influence of galactic dynamics on quenching star formation in galaxy spheroids

2020 ◽  
Vol 495 (1) ◽  
pp. 199-223 ◽  
Author(s):  
Jindra Gensior ◽  
J M Diederik Kruijssen ◽  
Benjamin W Keller
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Formation Rate ◽  
Free Fall ◽  
Galactic Centre ◽  
Causal Connection ◽  
Isolated Galaxies ◽  
Stellar Halo ◽  
Hydrodynamical Simulations ◽  
The Impact

ABSTRACT Quenched galaxies are often observed to contain a strong bulge component. The key question is whether this reflects a causal connection – can star formation be quenched dynamically by bulges or the spheroids of early-type galaxies? We systematically investigate the impact of these morphological components on star formation, by performing a suite of hydrodynamical simulations of isolated galaxies containing a spheroid. We vary the bulge mass and scale radius, while the total initial stellar, halo, and gas mass are kept constant, with a gas fraction of 5 per cent. In addition, we consider two different sub-grid star formation prescriptions. The first follows most simulations in the literature by assuming a constant star formation efficiency per free-fall time, whereas in the second model it depends on the gas virial parameter, following high-resolution simulations of turbulent fragmentation. Across all simulations, central spheroids increase the gas velocity dispersion towards the galactic centre. This increases the gravitational stability of the gas disc, suppresses fragmentation and star formation, and results in galaxies hosting extremely smooth and quiescent gas discs that fall below the galaxy main sequence. These effects amplify when using the more sophisticated, dynamics-dependent star formation model. Finally, we discover a pronounced relation between the central stellar surface density and star formation rate (SFR), such that the most bulge-dominated galaxies show the strongest deviation from the main sequence. We conclude that the SFR of galaxies is not only set by the balance between accretion and feedback, but carries a (sometimes dominant) dependence on the gravitational potential.

scholarly journals Irradiation Effects in Compact Binaries

2002 ◽  
Vol 187 ◽  
pp. 253-258
Author(s):  
Martin E. Beer ◽  
Philipp Podsiadlowski
Keyword(s):  
Binary Systems ◽  
Three Dimensional ◽  
Close Binary ◽  
Close Binaries ◽  
External Irradiation ◽  
Black Hole Binaries ◽  
Compact Binaries ◽  
Critical Configurations ◽  
Main Effects

AbstractIrradiation of the secondaries in close binary systems affects their appearance and can drastically change their internal structure and hence long-term evolution. In this paper we review the main effects of external irradiation in close binaries with compact primaries, such as the distortion of the shape of the secondary and the conditions for the occurrence of outer critical configurations, and apply these to normal X-ray binaries, including systems such as HZ Her/Her X-l, Vela X-l and black-hole binaries during outburst (e.g. Nova Sco). Particular emphasis will be given to the role of circulation driven by the external heating and the radiative surface stress. We have developed a three-dimensional fluid dynamics code for modelling these effects. We present initial results of self-consistent calculations for the circulation in irradiated systems and show how the inclusion of these effects is vital to the understanding and interpretation of any system where external irradiation of the secondary is significant.

scholarly journals Wind accretion in Cygnus X-1

2020 ◽  
Vol 637 ◽  
pp. A66 ◽  
Author(s):  
E. Meyer-Hofmeister ◽  
B. F. Liu ◽  
E. Qiao ◽  
R. E. Taam
Keyword(s):  
Black Hole ◽  
Stellar Wind ◽  
Binary Systems ◽  
Three Dimensional ◽  
Stable States ◽  
X Ray ◽  
Hard State ◽  
Hard Spectrum ◽  
Low Mass ◽  
Hydrodynamical Simulations

Context. Cygnus X-1 is a black hole X-ray binary system in which the black hole captures and accretes gas from the strong stellar wind emitted by its supergiant O9.7 companion star. The irradiation of the supergiant star essentially determines the flow properties of the stellar wind and the X-ray luminosity from the system. The results of three-dimensional hydrodynamical simulations of wind-fed X-ray binary systems reported in recent work reveal that the ionizing feedback of the X-ray irradiation leads to the existence of two stable states with either a soft or a hard spectrum. Aims. We discuss the observed radiation of Cygnus X-1 in the soft and hard state in the context of mass flow in the corona and disk, as predicted by the recent application of a condensation model. Methods. The rates of gas condensation from the corona to the disk for Cygnus X-1 are determined, and the spectra of the hard and soft radiation are computed. The theoretical results are compared with the MAXI observations of Cygnus X-1 from 2009 to 2018. In particular, we evaluate the hardness-intensity diagrams (HIDs) for its ten episodes of soft and hard states which show that Cygnus X-1 is distinct in its spectral changes as compared to those found in the HIDs of low-mass X-ray binaries. Results. The theoretically derived values of photon counts and hardness are in approximate agreement with the observed data in the HID. However, the scatter in the diagram is not reproduced. Improved agreement could result from variations in the viscosity associated with clumping in the stellar wind and corresponding changes of the magnetic fields in the disk. The observed dipping events in the hard state may also contribute to the scatter and to a harder spectrum than predicted by the model.

scholarly journals The impact of fallback on the compact remnants and chemical yields of core-collapse supernovae

2020 ◽  
Vol 495 (4) ◽  
pp. 3751-3762 ◽  
Author(s):  
Conrad Chan ◽  
Bernhard Müller ◽  
Alexander Heger
Keyword(s):  
Binding Energy ◽  
Gamma Ray ◽  
Three Dimensional ◽  
Explosion Energy ◽  
Core Collapse ◽  
Abundance Patterns ◽  
Small Set ◽  
The Impact ◽  
Disc Formation ◽  
Three Dimensional Simulations

ABSTRACT Fallback in core-collapse supernovae plays a crucial role in determining the properties of the compact remnants and of the ejecta composition. We perform three-dimensional simulations of mixing and fallback for selected non-rotating supernova models to study how explosion energy and asymmetries correlate with the remnant mass, remnant kick, and remnant spin. We find that the strongest kick and spin are imparted by partial fallback in an asymmetric explosion. Black hole (BH) kicks of several hundred $\mathrm{km}\, \mathrm{s}^{-1}$ and spin parameters of $\mathord {\sim }0.25$ can be obtained in this scenario. If the initial explosion energy barely exceeds the envelope binding energy, stronger fallback results, and the remnant kick and spin remain small. If the explosion energy is high with respect to the envelope binding energy, there is little fallback with a small effect on the remnant kick, but the spin-up by fallback can be substantial. For a non-rotating $12\, \mathrm{M}_\odot$ progenitor, we find that the neutron star is spun up to millisecond periods. The high specific angular momentum of the fallback material can also lead to disc formation around BHs. Fallback may thus be a pathway towards millisecond-magnetar or collapsar-type engines for hypernovae and gamma-ray bursts that does not require rapid progenitor rotation. Within our small set of simulations, none reproduced the peculiar layered fallback necessary to explain the metal-rich iron-poor composition of many carbon-enhanced metal-poor (CEMP) stars. Models with different explosion energy and different realizations of asymmetries may, however, be compatible with CEMP abundance patterns.

scholarly journals Surround and Squash: the impact of superbubbles on the interstellar medium in Scorpius–Centaurus OB2

2018 ◽  
Vol 619 ◽  
pp. A120 ◽  
Author(s):  
Martin G. H. Krause ◽  
Andreas Burkert ◽  
Roland Diehl ◽  
Katharina Fierlinger ◽  
Benjamin Gaczkowski ◽  
...  
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Massive Star ◽  
Massive Stars ◽  
Three Dimensional ◽  
X Rays ◽  
Hot Gas ◽  
Sky Survey ◽  
Hydrodynamical Simulations ◽  
The Impact

Context. Feedback by massive stars shapes the interstellar medium and is thought to influence subsequent star formation. The details of this process are under debate. Aims. We exploited observational constraints on stars, gas, and nucleosynthesis ashes for the closest region with recent massive-star formation, Scorpius–Centaurus OB2, and combined them with three-dimensional (3D) hydrodynamical simulations in order to address the physics and history of the Scorpius–Centaurus superbubble. Methods. We used published cold gas observations of continuum and molecular lines from Planck, Herschel, and APEX. We analysed the Galactic All Sky Survey (GASS) to investigate shell structures in atomic hydrogen, and used Hipparcos and Gaia data in combination with interstellar absorption against stars to obtain new constraints for the distance to the Hi features. Hot gas is traced in soft X-rays via the ROSAT all sky survey. Nucleosynthesis ejecta from massive stars were traced with new INTEGRAL spectrometer observations via 26Al radioactivity. We also performed 3D hydrodynamical simulations for the Sco–Cen superbubble. Results. Soft X-rays and a now more significant detection of 26Al confirm recent (≈1 Myr ago) input of mass, energy, and nucleosynthesis ejecta, likely from a supernova in the Upper Scorpius (USco) subgroup. We confirm a large supershell around the entire OB association and perform a 3D hydrodynamics simulation with a conservative massive star population that reproduces the morphology of the superbubble. High-resolution GASS observations reveal a nested, filamentary supershell. The filaments are possibly related to the Vishniac clumping instability, but molecular gas (Lupus I) is only present where the shell coincides with the connecting line between the subgroups of the OB association, suggesting a connection to the cloud, probably an elongated sheet, out of which the OB association formed. Stars have formed sequentially in the subgroups of the OB association and currently form in Lupus I. To investigate the impact of massive star feedback on extended clouds, we simulate the interaction of a turbulent cloud with the hot, pressurised gas in a superbubble. The hot gas fills the tenuous regions of the cloud and compresses the denser parts. Stars formed in these dense clumps would have distinct spatial and kinematic distributions. Conclusions. The combined results from observations and simulations are consistent with a scenario where dense gas was initially distributed in a band elongated in the direction now occupied by the OB association. Superbubbles powered by massive stars would then repeatedly break out of the elongated parent cloud, and surround and squash the denser parts of the gas sheet and thus induce more star formation. The expected spatial and kinematic distribution of stars is consistent with observations of Sco–Cen. The scenario might apply to many similar regions in the Galaxy and also to active galactic nucleus (AGN)-related superbubbles.

scholarly journals The Impact of Starspots on Mass and Age Estimates for Pre-main Sequence Stars

2015 ◽  
Vol 10 (S314) ◽  
pp. 91-94
Author(s):  
Garrett Somers ◽  
Marc H. Pinsonneault
Keyword(s):  
Binary Systems ◽  
Main Sequence ◽  
Late Type ◽  
Main Sequence Stars ◽  
Eclipsing Binary ◽  
Lithium Depletion ◽  
The Impact ◽  
Age Estimates ◽  
Hr Diagram

AbstractWe investigate the impact of starspots on the evolution of late-type stars during the pre-main sequence (pre-MS). We find that heavy spot coverage increases the radii of stars by 4–10%, consistent with inflation factors in eclipsing binary systems, and suppresses the rate of pre-MS lithium depletion, leading to a dispersion in zero-age MS Li abundance (comparable to observed spreads) if a range of spot properties exist within clusters from 3-10 Myr. This concordance with data implies that spots induce a range of radii at fixed mass during the pre-MS. These spots decrease the luminosity and Teff of stars, leading to a displacement on the HR diagram. This displacement causes isochrone derived masses and ages to be systematically under-estimated, and can lead to the spurious appearance of an age spread in a co-eval population.

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