Type Ia supernovae (SNe Ia) are thought to be the result of thermonuclear explosions in white dwarfs (WDs). Commonly considered formation pathways include two merging WDs (the double degenerate channel), and a single WD accreting material from a H or He donor (the single degenerate channel). Since the predicted SNe Ia rates from WD in binaries are thought to be insufficient to explain the observed SNe Ia rate, it is important to study similar interactions in higher-order multiple star systems such as triple systems. We use the evolutionary population synthesis code Multiple Stellar Evolution (MSE) to study stellar evolution, binary interactions and gravitational dynamics of the triple-star systems. Also, unlike previous studies, prescriptions are included to simultaneously take into account the single and double degenerate channels, and we consider triples across the entire parameter space (including those with tight inner binaries). We explore the impact of typically ignored or uncertain physics such as fly-bys and CE prescription parameters on our results. The majority of systems undergo circular mergers to explode as SNe Ia, while eccentric collisions contribute to $0.4-4$ per cent of SNe Ia events. The time-integrated SNe Ia rate from the triple channel is found to be $(3.60 \pm 0.04) \times {10^{-4}}\,\mathrm{M_{\odot}}^{-1}$ which is, surprisingly, similar to that of the isolated binary channel where the SNe Ia rate is $(3.2 \pm 0.1) \times {10^{-4}}\,\mathrm{M_{\odot}}^{-1}$. This implies that triples, when considering their entire parameter space, yield an important contribution to the overall SNe Ia rate.
Type Ia supernovae (SNe Ia) could arise from mergers of carbon-oxygen white dwarfs (WDs) triggered by Lidov-Kozai (LK) oscillations in hierarchical triple-star systems. However, predicted merger rates are several orders of magnitude lower than the observed SNe Ia rate. The low predicted rates can be attributed in part to the fact that many potential WD-merger progenitor systems, with high mutual orbital inclination, merge or interact before the WD stage. Recently, evidence was found for the existence of natal kicks imparted on WDs with a typical magnitude of 0.75 km/s. In triples, kicks change…
The fraction of stars which are in binaries or triples at the time of stellar death and the fraction of these systems which survive the supernova (SN) explosion are crucial constraints for evolution models and predictions for gravitational wave source populations. These fractions are also subject to direct observational determination. Here we search 10 supernova remnants (SNR) containing compact objects with proper motions for unbound binaries or triples using Gaia EDR3 and new statistical methods and tests for false positives. We confirm the one known example of an unbound binary, HD 37424 in…
The progenitor systems of Type-Ia supernovae (SNe Ia) are yet unknown. The collisional-triple SN Ia progenitor model posits that SNe Ia result from head-on collisions of binary white dwarfs (WDs), driven by dynamical perturbations by the tertiary stars in mild-hierarchical triple systems. To reproduce the Galactic SN Ia rate, at least ~30-55 per cent of all WDs would need to be in triple systems of a specific architecture. We test this scenario by searching the Gaia DR2 database for the postulated progenitor triples. Within a volume out to 120 pc, we search around Gaia-resolved double WDs with…
Recent studies on hypervelocity stars (HVSs) have generated a need to understand the high velocity limits of binary systems. If runaway binary systems with high movement speeds well in excess of 200km/s were to exist, it would have implications on how HVS candidates are selected, and our current understanding of how they form needs to be reinforced. In this paper, we explore the possibility that such high velocity runaway binaries (HVRBs) can be engendered by supernova explosions of the tertiary in close hierarchical triple systems. We find that such explosions can lead to significant remnant …
We have studied the sensitivity to variations in the the triple alpha and 12C(a,g)16O reaction rates of the production of 26Al, 44Ti, and 60Fe in core-collapse supernovae. We used the KEPLER code to model the evolution of 15, 20, and 25 solar mass stars to the onset of core collapse and simulated the ensuing supernova explosion using a piston model for the explosion. Calculations were performed for the Anders and Grevesse (1989) and Lodders (2003) abundances. Over a range of twice the experimental uncertainty, sigma, for each helium-burning rate, the production of 26Al, 60Fe, and their ratio v…
Dynamical scattering of binaries and triple systems of stars, planets, and compact objects may produce highly inclined triple systems subject to Kozai-Lidov (KL) oscillations, potentially leading to collisions, mergers, Type Ia supernovae, and other phenomena. We present the results of more than 400 million gravitational scattering experiments of binary-binary, triple-single, and triple-binary scattering. We compute the cross sections for all possible outcomes and explore their dependencies on incoming velocity, mass, semi-major axis, and eccentricity, including analytic fits and discussion of…
We investigate several aspects of black hole formation in failing core-collapse supernovae using 1D general-relativistic hydrodynamic simulations. We use the open-source code GR1D and incorporate into it nucleon-nucleon Bremsstrahlung, a crucial neutrino pair-production channel. We focus on how various thermal effects can influence the postbounce supernova evolution towards black hole formation. By performing simulations with and without nucleon-nucleon Bremsstrahlung, we investigate the sensitivity of black hole formation to thermal support in the protoneutron star. We also investigate delaye…
We examine a triple-star evolution that might lead to core collapse supernovae (CCSNe) in stellar populations that are too old to allow for single or binary evolution to form CCSNe, i.e., where the most massive stars that evolve off the main sequence have masses of ~4-5Mo. In the scenario we examine the most massive star in the triple system, of mass ~4-5Mo, transfers mass to an inner binary system at an orbital separation of ~100-1000Ro. The initial orbital separation of the inner binary is ~10-50Ro. The inner binary accretes most of the mass that the primary star loses and the two stars expa…
[Abridged]We investigate the long-term secular dynamics and Lidov-Kozai(LK) eccentricity oscillations of quadruple systems composed of two binaries at quadrupole and octupole order in the perturbing Hamiltonian. We show that the fraction of systems reaching high eccentricities is enhanced relative to triple systems, over a broader range of parameter space. We show that this fraction grows with time, unlike triple systems evolved at quadrupole order. This is fundamentally because with their additional degrees of freedom, quadruple systems do not have a maximal set of commuting constants of the …
We have found that individual presolar silicon carbide (SiC) dust grains from supernovae show a positive correlation between 49Ti and 28Si excesses, which is attributed to the radioactive decay of the short-lived (t1/2=330 day) 49V to 49Ti in the inner highly 28Si-rich Si/S zone. The 49V-49Ti chronometer constrains that these supernova SiC dust grains formed at least two years after their parent stars exploded. This result supports recent dust condensation calculations that predict a delayed formation of carbonaceous and SiC grains in supernovae. The astronomical observation of continuous buil…
We infer the progenitor mass distribution for 22 historic core-collapse supernovae (CCSNe) using a Bayesian hierarchical model. For this inference, we use the local star formation histories to estimate the age for each supernova (SN). These star formation histories often show multiple bursts of star formation; our model assumes that one burst is associated with the SN progenitor and the others are random bursts of star formation. The primary inference is the progenitor age distribution. Due to the limited number of historic SNe and highly uncertain star formation at young ages, we restrict our…
Double neutron star (DNS) systems are produced from massive binaries. A supernova (SN) explosion of an extremely stripped star is expected to occur at the final stage of DNS formation. This type of SN is called ultra-stripped SN (USSN). A recent research reveals that a type Ic SN, iPTF 14gqr (SN 2014ft) has low ejecta mass ($\approx0.2~\mathrm{M}_\odot$) and its progenitor has a helium envelope with its mass $\sim0.01~\mathrm{M}_\odot$. Then this SN is interpreted as an USSN, and this is the first discovery of the USSN. Furthermore, the observation of iPTF 14gqr provides us with some informati…
Physical collisions and close approaches between stars play an important role in the formation of exotic stellar systems. Standard theories suggest that collisions are rare, occurring only via random encounters between stars in dense clusters. We present a different formation pathway, the triple evolution dynamical instability (TEDI), in which mass loss in an evolving triple star system causes orbital instability. The subsequent chaotic orbital evolution of the stars triggers close encounters, collisions, exchanges between the stellar components, and the dynamical formation of eccentric compac…
Because core-collapse supernovae are the explosions of massive stars, which have relatively short lifetimes, they occur almost exclusively in galaxies with active star formation. On the other hand, the Type Ibn supernova PS1-12sk exploded in an environment much more typical of thermonuclear (Type Ia) supernovae: on the outskirts of the brightest elliptical galaxy in a galaxy cluster. The lack of any obvious star formation at that location presented a challenge to models of Type Ibn supernovae as the explosions of very massive Wolf-Rayet stars. Here we present a supplementary search for star fo…
The millisecond pulsar in a triple system (PSR J0337+1715, recently discovered by Ransom et al.) is an unusual neutron star with two orbiting white dwarfs. The existence of such a system in the Galactic field poses new challenges to stellar astrophysics for understanding evolution, interactions and mass-transfer in close multiple stellar systems. In addition, this system provides the first precise confirmation for a very wide-orbit system of the white dwarf mass-orbital period relation. Here we present a self-consistent, semi-analytical solution to the formation of PSR J0337+1715. Our model co…
Supernovae (SNe) should both frequently have a binary companion at death and form significant amounts of dust. This implies that any binary companion must lie at the center of an expanding dust cloud and the variable obscuration of the companion as the SN remnant (SNR) expands will both unambiguously mark the companion and allow the measurement of the dust content through absorption rather than emission for decades after the explosion. However, sufficiently hot and luminous companions can suppress dust formation by rapidly photo-ionizing the condensible species in the ejecta. This provides a m…
We consider dust formation during the ejection of the hydrogen envelope of a red supergiant during a failed supernova (SN) creating a black hole. While the dense, slow moving ejecta are very efficient at forming dust, only the very last phases of the predicted visual transient will be obscured. The net grain production consists of ~0.01 solar masses of very large grains (10 to 1000 microns). This means that failed SNe could be the source of the very large extrasolar dust grains identified by Ulysses, Galileo and radar studies of meteoroid re-entry trails rather than their coming from an ejecti…
The formation of Black Hole (BH) Low-Mass X-ray Binaries (LMXB) poses a theoretical challenge, as low-mass companions are not expected to survive the common-envelope scenario with the BH progenitor. Here we propose a formation mechanism that skips the common-envelope scenario and relies on triple-body dynamics. We study the evolution of hierarchical triples, following the secular dynamical evolution up to the octupole-level of approximation, including general relativity, tidal effects and post-main-sequence evolution, such as mass loss, changes to stellar radii and supernovae. During the dynam…
Most back hole and neutron star progenitors are found in triples or higher multiplicity systems. Here, we present a new triple stellar evolution code, ${\tt TSE}$, which simultaneously takes into account the physics of the stars and their gravitational interaction. ${\tt TSE}$ is used to simulate the evolution of massive stellar triples in the galactic field from the zero-age-main-sequence until they form compact objects. To this end, we implement initial conditions that incorporate the observed high correlation between the orbital parameters of early-type stars. We show that the interaction w…
In the last decade there has been a remarkable increase in our knowledge about core-collapse supernovae (CC-SNe), and the birthplace of neutron stars, from both the observational and the theoretical point of view. Since the 1930's, with the first systematic supernova search, the techniques for discovering and studying extragalactic SNe have improved. Many SNe have been observed, and some of them, have been followed through efficiently and with detail. Furthermore, there has been a significant progress in the theoretical modelling of the scenario, boosted by the arrival of new generations of su…
The rate of type Ia supernovae (SNe Ia) in a galaxy depends not only on stellar mass, but also on star formation history. Here we show that two simple observational quantities ($g-r$ or $u-r$ host galaxy color, and $r$-band luminosity), coupled with an assumed delay time distribution (the rate of SNe Ia as a function of time for an instantaneous burst of star formation), are sufficient to accurately determine a galaxy's SN Ia rate, with very little sensitivity to the precise details of the star formation history. Using this result, we compare observed and predicted color distributions of SN Ia…
The inclusion of molecular physics is an important piece that tends to be missing from the puzzle when modeling the spectra of supernovae (SNe). Molecules have both a direct impact on the spectra, particularly in the infrared, and an indirect one as a result of their influence on certain physical conditions, such as temperature. In this paper, we aim to investigate molecular formation and non-local thermodynamic equilibrium (NLTE) cooling, with a particular focus on CO, the most commonly detected molecule in supernovae. We also aim to determine the dependency of supernova chemistry on physical…
We present ultraviolet line identifications of near maximum-light HST observations of SN 2011fe using synthetic spectra generated from both SYNOW and $\texttt{PHOENIX}$. We find the spectrum to be dominated by blends of iron group elements Fe, Co, and Ni (as expected due to heavy line blanketing by these elements in the UV) and for the first time identify lines from C IV and Si IV in a supernova spectrum. We also find that classical delayed detonation models of Type Ia supernovae are able to accurately reproduce the flux levels of SN 2011fe in the UV. Further analysis reveals that photionizati…
We use the star formation history map of the Large Magellanic Cloud to study the sites of the eight smallest (and presumably youngest) supernova remnants in the Cloud: SN 1987A, N158A, N49, and N63A (core collapse remnants), 0509-67.5, 0519-69.0, N103B, and DEM L71 (Type Ia remnants). The local star formation histories provide unique insights into the nature of the supernova progenitors, which we compare with the properties of the supernova explosions derived from the remnants themselves and from supernova light echoes. We find that all the core collapse supernovae that we have studied are ass…
We present results of a systematic study of failing core-collapse supernovae and the formation of stellar-mass black holes (BHs). Using our open-source general-relativistic 1.5D code GR1D equipped with a three-species neutrino leakage/heating scheme and over 100 presupernova models, we study the effects of the choice of nuclear equation of state (EOS), zero-age main sequence (ZAMS) mass and metallicity, rotation, and mass-loss prescription on BH formation. We find that the outcome, for a given EOS, can be estimated, to first order, by a single parameter, the compactness of the stellar core at …
In dense stars such as collapsing cores of supernovae and neutron stars, nuclear "pasta" such as rod-like and slab-like nuclei are speculated to exist. However, whether or not they are actually formed in supernova cores is still unclear. Here we solve this problem by demonstrating that a lattice of rod-like nuclei is formed from a bcc lattice by compression. We also find that the formation process is triggered by an attractive force between nearest neighbor nuclei, which starts to act when their density profile overlaps, rather than the fission instability. We also discuss the connection betwe…
The scaling of the rate of type Ia Supernovae (SNIa) with the parent galaxies' color provides information on the distribution of the delay times (DTD) of the SNIa progenitors. We show that this information appears to depend on the photometric bands used to trace the stellar age distribution and mass-to-light ratio in the parent galaxies. Using both (U-V) and (B-K) colors to constrain the star formation history, we model the SNIa rate as a function of morphological galaxy type for different DTDs. The comparison with the observed rate per unit B and K band luminosity yields consistent results, a…
We present evolutionary pathways for creating hot subdwarf OB (sdOB) stars from hierarchical triple configurations. We use the population synthesis code Multiple Stellar Evolution (MSE) to follow the stellar, binary, and gravitational dynamical evolution of triple-star systems. To ascertain the effect of the outer tertiary, we also consider the evolution of the inner binary with the tertiary component removed. We find we are able to create sdOB stars in single, binary and triple configurations. We also demonstrate that it is possible to form sdOBs in systems which undergo triple common envelop…
There is currently a severe discrepancy between theoretical models of dust formation in core-collapse supernovae (CCSNe), which predict $\gtrsim 0.01$ M$_\odot$ of ejecta dust forming within $\sim 1000$ days, and observations at these epochs, which infer much lower masses. We demonstrate that, in the optically thin case, these low dust masses are robust despite significant observational and model uncertainties. For a sample of 11 well-observed CCSNe, no plausible model reaches carbon dust masses above $10^{-4}$ M$_\odot$, or silicate masses above $\sim 10^{-3}$ M$_\odot$. Optically thick model…
In supernova cores, nuclear "pasta" phases such as triangular lattice of rod-like nuclei and layered structure of slab-like nuclei are considered to exist. However, it is still unclear whether or not they are actually formed in collapsing supernova cores. Using {\it ab-initio} numerical simulations called the Quantum Molecular Dynamics (QMD), we here solve this problem by demonstrating that a lattice of rod-like nuclei is formed from a bcc lattice by compression. We also find that, in the transition process, the system undergoes zigzag configuration of elongated nuclei, which are formed by a f…
We present an investigation of the optical spectra of 264 low-redshift (z < 0.2) Type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory, an untargeted transient survey. We focus on velocity and pseudo-equivalent width measurements of the Si II 4130, 5972, and 6355 A lines, as well those of the Ca II near-infrared (NIR) triplet, up to +5 days relative to the SN B-band maximum light. We find that a high-velocity component of the Ca II NIR triplet is needed to explain the spectrum in ~95 per cent of SNe Ia observed before -5 days, decreasing to ~80 per cent at maximum. The averag…
Infrared (IR) observations of core collapse supernovae (CCSNe) have been used to infer the mass of dust that has formed in their ejecta. A plot of inferred dust masses versus supernova (SN) ages shows a trend of increasing dust mass with time, spanning a few decades of observations. This trend has been interpreted as evidence for the slow and gradual formation of dust in CCSNe. Observationally, the trend exhibits a $ t^2$ behavior, exactly what is expected from an expanding optically thick ejecta. In this case, the observed dust resides in the infrared (IR)-thin "photosphere" of the ejecta, an…
We investigate the formation of dust grains in the ejecta of Type Ia supernovae (SNe Ia), adopting the carbon-deflagration W7 model. In the calculations of dust formation, we apply the nucleation and grain growth theory and consider the two cases with and without formation of CO and SiO molecules. The results of the calculations show that for the sticking probability of alpha_j=1, C, silicate, Si, and FeS grains can condense at early times of ~100--300 days after the explosion, whereas Fe and SiC grains cannot form substantially. Due to the low gas density in SNe Ia with no H-envelope, the ave…
We study the spinning down time scale of rapidly rotating white dwarfs (WDs) in the frame of the core-degenerate (CD) scenario for type Ia supernovae (SNe Ia). In the CD scenario the Chandrasekhar or super-Chandrasekhar mass WD is formed at the termination of the common envelope phase or during the planetary nebula phase, from a merger of a WD companion with the hot core of a massive asymptotic giant branch star. In the CD scenario the rapidly rotating WD is formed shortly after the stellar formation episode, and the delay from stellar formation to explosion is basically determined by the spin…
Core-collapse supernovae are considered to be important contributors to the primitive dust enrichment of the interstellar medium in the high-redshift universe. Theoretical models of dust formation in stellar explosions have so far provided controversial results and a generally poor fit to the observations of dust formation in local supernovae. We present a new methodology for the calculation of carbonaceous dust formation in young supernova remnants. Our new technique uses both the nucleation theory and a chemical reaction network to allow us to compute the dust growth beyond the molecular lev…
In the core-degenerate (CD) scenario for the formation of Type Ia supernovae (SNe) the Chandrasekhar or super-Chandrasekhar mass white dwarf (WD) is formed at the termination of the common envelope phase or during the planetary nebula phase, from a merger of a WD companion with the hot core of a massive asymptotic giant branch (AGB) star. The WD is destructed and accreted onto the more massive core. In the CD scenario the rapidly rotating WD is formed shortly after the stellar formation episode, and the delay from stellar formation to explosion is basically determined by the spin-down time of …
Revisiting the formation of molecules and dust in core collapse supernovae
Université de Montpellier, CNRS（蒙彼利埃大学，法国国家科学研究中心）；Consejo Superior de Investigaciones Cientificas, Instituto de Fisica Fundamental（西班牙高等科学研究理事会，基础物理研究所）
$η$ Carinae is an extraordinary massive star famous for its 19th century Great Eruption and the surrounding Homunculus nebula ejected in that event. The cause of this eruption has been the centre of a long-standing mystery. Recent observations, including light-echo spectra of the eruption, suggest that it most likely resulted from a stellar merger in an unstable triple system. Here we present a detailed set of theoretical calculations for this scenario; from the dynamics of unstable triple systems and the mass ejection from close binary encounters, to the mass outflow from the eruption caused …
The time delay between the formation of a population of stars and the onset of type Ia supernovae (SNe Ia) sets important limits on the masses and nature of SN Ia progenitors. Here we use a new observational technique to measure this time delay by comparing the spatial distributions of SNe Ia to their local environments. Previous work attempted such analyses encompassing the entire host of each SN Ia, yielding inconclusive results. Our approach confines the analysis only to the relevant portions of the hosts, allowing us to show that even so-called "prompt" SNe Ia that trace star-formation on …
Recent investigations of the WD + MS channel of Type Ia supernovae (SNe Ia) imply that this channel may be the main contribution to the old population (>1Gyr) of SNe Ia. In the WD + MS channel, the WD could accrete material from a main-sequence or a slightly evolved star until it reaches the Chandrasekhar mass limit. The companions in this channel would survive after SN explosion and show distinguishing properties. In this Letter, based on SN Ia production regions of the WD + MS channel and three formation channels of WD + MS systems, we performed a detailed binary population synthesis study t…
We study the implementation of mechanical feedback from supernovae (SNe) and stellar mass loss in galaxy simulations, within the Feedback In Realistic Environments (FIRE) project. We present the FIRE-2 algorithm for coupling mechanical feedback, which can be applied to any hydrodynamics method (e.g. fixed-grid, moving-mesh, and mesh-less methods), and black hole as well as stellar feedback. This algorithm ensures manifest conservation of mass, energy, and momentum, and avoids imprinting 'preferred directions' on the ejecta. We show that it is critical to incorporate both momentum and thermal e…
The formation of very wide binaries, such as the alpha Cen system with Proxima (also known as alpha Centauri C) separated from alpha Centauri (which itself is a close binary A/B) by 15000 AU, challenges current theories of star formation, because their separation can exceed the typical size of a collapsing cloud core. Various hypotheses have been proposed to overcome this problem, including the suggestion that ultra-wide binaries result from the dissolution of a star cluster - when a cluster star gravitationally captures another, distant, cluster star. Recent observations have shown that very …
Carbon is produced during the helium burning phase of sufficiently massive stars through the triple alpha process. The $0^+$ energy level of the carbon nucleus allows for resonant nuclear reactions, which act to greatly increase the carbon yields compared to the non-resonant case. Many authors have argued that small changes to the energy level of this resonance would lead to a significantly lower carbon abundance in the universe, and this sensitivity is often considered an example of fine-tuning. By considering spallation reactions occuring during the process of planet formation, this paper pr…
We present the evolution of rotational directions of circumstellar disks in a triple protostar system simulated from a turbulent molecular cloud core with no magnetic field. We find a new formation pathway of a counter-rotating circumstellar disk in such triple systems. The tertiary protostar forms via the circumbinary disk fragmentation and the initial rotational directions of all the three circumstellar disks are almost parallel to that of the orbital motion of the binary system. Their mutual gravito-hydrodynamical interaction for the subsequent $\sim10^4\thinspace\rm{yr}$ greatly disturbs t…
We identify a "supernova rate problem": the measured cosmic core-collapse supernova rate is a factor of ~ 2 smaller (with significance ~ 2 sigma) than that predicted from the measured cosmic massive-star formation rate. The comparison is critical for topics from galaxy evolution and enrichment to the abundance of neutron stars and black holes. We systematically explore possible resolutions. The accuracy and precision of the star formation rate data and conversion to the supernova rate are well supported, and proposed changes would have far-reaching consequences. The dominant effect is likely t…
We present a study of the properties of the host galaxies of unusual transient objects of two types, both being sub-luminous compared with the major classes of supernovae. Those of one type exhibit unusually strong calcium features, and have been termed 'Ca-rich'. Those of the second type, with SN2002cx as the prototype and SN2008ha as the most extreme example to date, have some properties in common with the first, but show typically lower ejecta velocities, and different early spectra. We confirm important differences in the environments of the two types, with the Ca-rich transients preferent…
We demonstrate that using up to seven stellar abundance ratios can place observational constraints on the star formation histories (SFHs) of Local Group dSphs, using the Sculptor dSph as a test case. We use a one-zone chemical evolution model to fit the overall abundance patterns of $α$ elements (which probe the core-collapse supernovae that occur shortly after star formation), $s$-process elements (which probe AGB nucleosynthesis at intermediate delay times), and iron-peak elements (which probe delayed Type Ia supernovae). Our best-fit model indicates that Sculptor dSph has an ancient SFH, co…
We have studied the sensitivity of supernova production of the gamma emitting nuclei 26Al, 44Ti and 60Fe to variations of the rates of the triple alpha and 12C(alpha, gamma) reactions. Over a range of twice their experimental uncertainties we find variations in the production of 60Fe by more than a factor of five. Smaller variations, about a factor of two to three, were observed for 26Al and 44Ti. The yields of these isotopes change significantly when the abundances of Lodders (2003) are used instead of those of Anders and Grevesse (1989). These sensitivities will limit conclusions based on a …
We analyze the first giant molecular cloud (GMC) simulation to follow the formation of individual stars and their feedback from jets, radiation, winds, and supernovae, using the STARFORGE framework in the GIZMO code. We evolve the GMC for $\sim 9 \rm Myr$, from initial turbulent collapse to dispersal by feedback. Protostellar jets dominate feedback momentum initially, but radiation and winds cause cloud disruption at $\sim 8\%$ star formation efficiency (SFE), and the first supernova at $8.3 \rm Myr$ comes too late to influence star formation significantly. The per-freefall SFE is dynamic, acc…
We review the observational evidence for dust formation in Wolf-Rayet binary systems and in Type II Supernova ejecta. Existing theoretical models describing the condensation of solids in carbon-rich Wolf-Rayet stars and in Supernovae close by and at high redshift are discussed. We describe new modeling of carbon- and oxygen-based grain nucleation using a chemical kinetic approach applied to the ejecta of massive pair-instability Supernovae in the early universe. Finally, dust formation processes in colliding wind regions of WC binary systems are discussed.
The role of triple evolution in the formation of LISA double white dwarfs
Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理研究所）；Radboud University（拉德堡德大学）；Anton Pannekoek Institute for Astronomy, University of Amsterdam（阿姆斯特丹大学安东·潘内科克天文研究所）；Ludwig-Maximilians-Universität München（慕尼黑路德维希-马克西米利安大学）
