Binary Parameters Research Articles

A machine-learning method to derive the parameters of contact binaries

Abstract Contact binary stars are important research objects in astrophysics. The calculation speed of deriving the parameters of contact binaries with the Wilson–Devinney program and the Phoebe with Markov chain Monte Carlo (MCMC) program is relatively slow. It is unrealistic to derive the parameters in batches with the program for sky survey data. We obtain a neural network model of supervised learning with the training of synthetic light curves with Phoebe. We calculate the parameters of eight special targets from the simulated data and the Kepler data. Then, we generate the new light curve to fit the light curve of the special target base on these parameters. The correlation index R2 of the fitting result is more than 0.98. The method can be used to fit the target which has orbital inclinations greater than 50°. By fitting the Kepler data and the observed data on the ground, the method has a good generalization ability to these targets, which have some noise and some starspots. The calculation speed of one light curve with this method is less than seconds. We can derive the parameters quickly in batches to undertake some statistical work for sky survey data with the method.

Observability of inflated companion stars after supernovae in massive binaries

ABSTRACT We carry out a systematic study of the response of companion stars in massive binaries after being impacted by supernova (SN) ejecta. A total of 720 1D stellar evolution calculations are performed to follow the inflation and contraction of the star in response to the energy injection and how it depends on various parameters. We find that the maximum luminosity achieved during the inflated phase is only dependent on the stellar mass and we derive an analytic formula to describe the relation. There is also a tight correlation between the duration of expansion and the intersected energy. These correlations will be useful to constrain pre-SN binary parameters from future detections of inflated companions. We also discuss the possible outcomes of the binary system when the companion inflation is taken into account. Based on simple binary population synthesis, we estimate that ∼1–3 per cent of stripped-envelope SNe may have observable inflated companions. Finally, we apply our models to the observed companion of SN 2006jc and place strong constraints on the possible pre-SN binary parameters.

Modeling solubility of amino acids and peptides in water and in water+2-propanol mixtures: PC-SAFT vs. gE models

Amino acids and peptides are essential components for many industrial branches. Knowledge on the solubility behavior is required in purification processes, which often involve crystallization as main unit operation. Since the determination of experimental solubility data is expensive, thermodynamic modeling is meaningful towards reducing the experimental effort. Modeling is usually based on a solid-liquid equilibrium condition that requires the melting properties of the solids. For amino acids and peptides such data is now available, and three gE models (Wilson, NRTL, UNIQUAC) were applied in this work to model solubility in water as well as in water + 2-propanol. The new melting properties were used as input data and binary parameters for each model were fitted to experimental solubility data of the amino acids and peptides in water. Modeling solubility in water + 2-propanol required additional parameters. Binary parameters between water and 2-propanol were fitted to vapor-liquid-equilibrium data, and binary parameters between amino acid and 2-propanol as well as between peptide and 2-propanol were fitted to solubility data in water + 2-propanol mixtures. In general, the gE models allowed describing the solubility in water, while some inaccuracies were observed for the temperature dependence of the modeled solubility. Further, the decrease of solubility upon 2-propanol addition was modeled qualitatively correct using the gE models. The Wilson model was less accurate than NRTL and UNIQUAC, where the latter yielded similar results. The results were finally compared to PC-SAFT, which shows a dramatically improved modeling accuracy while using less binary parameters.

Energy-efficient heterogeneous azeotropic distillation coupling with pressure swing distillation for the separation of IPA/DIPE/Water mixture

Isopropyl alcohol/diisopropylether/water mixture is commonly produced in the IPA production process. Improvement of the separation of water-rich mixture is crucial to achieve green production of IPA. Conventional extractive distillation proposed in recent literature was reproduced by revised VLLE binary parameters to ensure the accuracy of simulation results. A newly proposed energy-efficient process is developed based on the idea of liquid-liquid separation coupling with pressure-swing distillation in this work. Thorough consideration in different distillation regions on the complex residue curve map and optimization of the process parameters using sequential iterative method lead to a simple configuration of separation process without needing of foreign component as entrainer. Further heat-integrated strategies are analyzed and implemented in the proposed system to ensure the good energy-efficiency of the process. The final heat-integrated novel design flowsheet can save up to 33.0% in total operating cost and 23.0% in total annual cost as compared to extractive-distillation system proposed in recent literature, showing the potential of this energy-efficient configuration applied on mixture with the most complicated residue curve map.

Cultural evolution leads to vocal iconicity in an experimental iterated learning task

Abstract Experimental and cross-linguistic studies have shown that vocal iconicity is prevalent in words that carry meanings related to size and shape. Although these studies demonstrate the importance of vocal iconicity and reveal the cognitive biases underpinning it, there is less work demonstrating how these biases lead to the evolution of a sound symbolic lexicon in the first place. In this study, we show how words can be shaped by cognitive biases through cultural evolution. Using a simple experimental setup resembling the game telephone, we examined how a single word form changed as it was passed from one participant to the next by a process of immediate iterated learning. About 1,500 naïve participants were recruited online and divided into five condition groups. The participants in the control-group received no information about the meaning of the word they were about to hear, while the participants in the remaining four groups were informed that the word meant either big or small (with the meaning being presented in text), or round or pointy (with the meaning being presented as a picture). The first participant in a transmission chain was presented with a phonetically diverse word and asked to repeat it. Thereafter, the recording of the repeated word was played for the next participant in the same chain. The sounds of the audio recordings were then transcribed and categorized according to six binary sound parameters. By modelling the proportion of vowels or consonants for each sound parameter, the small-condition showed increases of front unrounded vowels and the pointy-condition increases of acute consonants. The results show that linguistic transmission is sufficient for vocal iconicity to emerge, which demonstrates the role non-arbitrary associations play in the evolution of language.

V680 Mon – a young mercury–manganese star in an eclipsing heartbeat system

ABSTRACT Chemically peculiar stars in eclipsing binary systems are rare objects that allow the derivation of fundamental stellar parameters and important information on evolutionary status and the origin of the observed chemical peculiarities. Here we present an investigation of the known eclipsing binary system BD+09 1467 = V680 Mon. Using spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and own observations, we identify the primary component of the system as a mercury–manganese (HgMn/CP3) star (spectral type kB9 hB8 HeB9 V HgMn). Furthermore, photometric time series data from the Transiting Exoplanet Survey Satellite (TESS) indicate that the system is a ‘heartbeat star’, a rare class of eccentric binary stars with short-period orbits that exhibit a characteristic signature near the time of periastron in their light curves due to the tidal distortion of the components. Using all available photometric observations, we present an updated ephemeris and binary system parameters as derived from a modelling of the system with the elisa code, which indicate that the secondary star has an effective temperature of Teff = $8300_{-200}^{+200}$ (spectral type ∼A4). V680 Mon is only the fifth known eclipsing CP3 star, and the first one in a heartbeat binary. Furthermore, our results indicate that the star is located on the zero-age main sequence and a possible member of the open cluster NGC 2264. As such, it lends itself perfectly for detailed studies and may turn out to be a keystone in the understanding of the development of CP3 star peculiarities.

Population synthesis on ultra-luminous X-ray sources with an accreting neutron star: Wind Roche-lobe overflow cases

Very recently, wind Roche-lobe overflow (WRLOF) has been suggested as a possible mass transfer mechanism for ultra-luminous X-ray sources (ULXs) and, to date, two neutron-star (NS) ULXs (i.e., NGC 7793 P13 and NGC 300 ULX-1) are remarkable and hard to understand in the current, usual RLOF picture. In this work, we test if the two sources could fit into the WRLOF paradigm. By using an evolutionary population synthesis method, we modeled the population of NS ULXs with (super)giant donors, taking the WRLOF accretion mode into account. We find that the population of wind-fed NS ULXs in the WRLOF mode is distinct in numbers and binary parameters from that in the traditional Bondi-Hoyle-Lyttleton mode, and it is strongly metallicity dependent. The number of NS ULXs with (super)giant donors can be enhanced greatly, by one or two orders of magnitude, depending on the metallicity adopted. Sources with massive (∼15−40 M⊙) (super)giant donors dominate wind-fed NS ULXs in the very low metallicities, while sources in near solar cases are dominated by a red supergiant with a lower mass M2 < 10 M⊙ instead. Moreover, the two NS ULXs can be well reproduced in the WRLOF paradigm, which significantly enriches our understanding of the nature of ULXs and the population. We also present the current distributions of binary parameters of wind-fed NS ULXs, which may be further testified by future high-resolution optical and X-ray observations of these populations.

Misaligned Twin Molecular Outflows from the Class 0 Protostellar Binary System VLA 1623A Unveiled by ALMA

Abstract We present the results of ALMA observations toward the low-mass Class 0 binary system VLA 1623Aab in the Ophiuchus molecular cloud in 12CO, 13CO, and C18O(2–1) lines. Our 12CO (J = 2–1) data reveal that the VLA 1623 outflow consists of twin spatially overlapped outflows/jets. The redshifted northwestern jet exhibits three cycles of wiggle with a spatial period of 1360 ± 10 au, corresponding to a time period of 180 yr. The wiggle-like structure is also found in the position–velocity (PV) diagram, showing an amplitude in the velocity of about 0.9 km s−1. Both the period and velocity amplitude of the wiggle are roughly consistent with those expected from the binary parameters, i.e., the orbital period (460 ± 20 yr) and the Keplerian velocity (2.2 km s−1). Our 13CO and C18O images show a dense gas nature in the two centimeter/millimeter sources, VLA 1623B and W, and its relation to the outflows, and strongly support the previous interpretation that both are shocked cloudlets. The driving sources of the twin molecular outflows are, therefore, likely to be the VLA 1623Aab binary. The outflow axes of the two molecular outflows are estimated to be inclined by 70° to each other across the plane of sky, implying that protostellar disks are also misaligned by . Such nature together with a small binary separation of 34 au in one of the youngest protobinary systems seems difficult to explain by disk fragmentation in quiescent environments. Other effects such as turbulence probably play roles.

Exact computation of maximum rank correlation estimator

SummaryIn this paper we provide a computation algorithm to get a global solution for the maximum rank correlation estimator using the mixed integer programming (MIP) approach. We construct a new constrained optimization problem by transforming all indicator functions into binary parameters to be estimated and show that it is equivalent to the original problem. We also consider an application of the best subset rank prediction and show that the original optimization problem can be reformulated as MIP. We derive the nonasymptotic bound for the tail probability of the predictive performance measure. We investigate the performance of the MIP algorithm by an empirical example and Monte Carlo simulations.

Binarized graph neural network

Recently, there have been some breakthroughs in graph analysis by applying the graph neural networks (GNNs) following a neighborhood aggregation scheme, which demonstrate outstanding performance in many tasks. However, we observe that the parameters of the network and the embedding of nodes are represented in real-valued matrices in existing GNN-based graph embedding approaches which may limit the efficiency and scalability of these models. It is well-known that binary vector is usually much more space and time efficient than the real-valued vector. This motivates us to develop a binarized graph neural network to learn the binary representations of the nodes with binary network parameters following the GNN-based paradigm. Our proposed method can be seamlessly integrated into the existing GNN-based embedding approaches to binarize the model parameters and learn the compact embedding. Extensive experiments indicate that the proposed binarized graph neural network, namely BGN, is orders of magnitude more efficient in terms of both time and space while matching the state-of-the-art performance.

A statistical approach to evaluate the influence of geometric parameters on fracture of the cell walls in porous aluminum alloy

Fracture of a cell wall causes compressive stress drop in compression of porous metals with unidirectional pores. If such a phenomenon occurs, energy absorption and its efficiency will decrease. This research investigated the dependency of the fractures on initial geometry and the influence of geometric parameters on fractures by statistical analyses. Numerical simulations of compression tests were conducted using the finite element method for eleven specimens with different geometries to efficiently collect data on the occurrence of fractures during compression. A total of eight geometric quantitative parameters were defined for each cell wall which describe the shape of it, its location in the specimen, and the shape of its surrounding cell walls. An additional binary parameter was used to monitor the occurrence of the fracture in the structure. A total of 568 data points were analyzed by a support vector machine and a logistic regression. The prediction results of the support vector machine achieved approximately 0.7 in F1 score, which indicates that the fracture location highly depends on initial geometry. Odds ratios of the logistic regression model show that five out of eight input parameters have a significant influence on the fractures at a significance level of 0.05. Furthermore, it was revealed that cell walls with small relative thickness and relatively small angle, connected to upper and lower cell walls with larger angles, and located near the side surfaces, are more likely to fracture.

Spin-orbit misalignments in tertiary-induced binary black-hole mergers: Theoretical analysis

Black-hole (BH) binary mergers driven by gravitational perturbations of tertiary companions constitute an important class of dynamical formation channels for compact binaries detected by LIGO/VIRGO. Recent works have examined numerically the combined orbital and spin dynamics of BH binaries that undergo large Lidov-Kozai (LK) eccentricity oscillations induced by a highly inclined companion and merge via gravitational wave radiation. However, the extreme eccentricity variations make such systems difficult to characterize analytically. In this paper, we develop an analytical formalism for understanding the spin dynamics of binary BHs undergoing LK-induced mergers. We show that, under certain conditions, the eccentricity oscillations of the binary can be averaged over to determine the long-term behavior of the BH spin in a smooth way. In particular, we demonstrate that the final spin-orbit misalignment angle $\theta_{\rm sl}$ is often related to the binary's primordial spin orientation through an approximate adiabatic invariant. Our theory explains the "$90^\circ$ attractor" (as found in recent numerical studies) for the evolution of $\theta_{\rm sl}$ when the initial BH spin is aligned with the orbital axis and the octupole LK effects are negligible -- such a "$90^\circ$ attractor" would lead to a small binary effective spin parameter $\chi_{\rm eff}\sim 0$ even for large intrinsic BH spins. We calculate the deviation from adiabaticity in closed form as a function of the initial conditions. We also place accurate constraints on when this adiabatic invariant breaks down due to resonant spin-orbit interactions. We consider both stellar-mass and supermassive BH tertiary companions, and provide simple prescriptions for determining analytically the final spin-orbit misalignment angles of the merging BH binaries.

All-sky search in early O3 LIGO data for continuous gravitational-wave signals from unknown neutron stars in binary systems

Rapidly spinning neutron stars are promising sources of continuous gravitational waves. Detecting such a signal would allow probing of the physical properties of matter under extreme conditions. A significant fraction of the known pulsar population belongs to binary systems. Searching for unknown neutron stars in binary systems requires specialized algorithms to address unknown orbital frequency modulations. We present a search for continuous gravitational waves emitted by neutron stars in binary systems in early data from the third observing run of the Advanced LIGO and Advanced Virgo detectors using the semicoherent, GPU-accelerated, binaryskyhough pipeline. The search analyzes the most sensitive frequency band of the LIGO detectors, 50–300 Hz. Binary orbital parameters are split into four regions, comprising orbital periods of three to 45 days and projected semimajor axes of two to 40 light seconds. No detections are reported. We estimate the sensitivity of the search using simulated continuous wave signals, achieving the most sensitive results to date across the analyzed parameter space.5 MoreReceived 23 December 2020Accepted 3 February 2021DOI:https://doi.org/10.1103/PhysRevD.103.064017© 2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasGravitational wave detectionGravitational wave sourcesGravitational wavesPhysical SystemsBinary starsNeutron stars & pulsarsGravitation, Cosmology & Astrophysics

Axisymmetric models for neutron star merger remnants with realistic thermal and rotational profiles

Merging neutron stars are expected to produce hot, metastable remnants in rapid differential rotation, which subsequently cool and evolve into rigidly rotating neutron stars or collapse to black holes. Studying this metastable phase and its further evolution is essential for the prediction and interpretation of the electromagnetic, neutrino, and gravitational signals from such a merger. In this work, we model binary neutron star merger remnants and propose new rotation and thermal laws that describe post-merger remnants. Our framework is capable to reproduce quasi-equilibrium configurations for generic equations of state, rotation and temperature profiles, including nonbarotropic ones. We demonstrate that our results are in agreement with numerical relativity simulations concerning bulk remnant properties like the mass, angular momentum, and the formation of a massive accretion disk. Because of the low computational cost for our axisymmetric code compared to full 3+1-dimensional simulations, we can perform an extensive exploration of the binary neutron star remnant parameter space studying several hundred thousand configurations for different equation of states.

Modeling of Phase Equilibria and Surface Tension for N,N-Dimethylcyclohexylamine + Alcohol Mixtures at Different Temperatures

Surface tension and phase equilibria of N,N-dimethylcyclohexylamine (DMCA) mixtures with alcohol (propanol, iso-propanol, butanol, and iso-butanol) were modeled over the whole range of composition and different temperature ranging from (288.15 to 308.15) K. The predictive results of the Peng–Robinson equation of state with quadratic mixing rule indicated that the DMCA + alcohol mixtures are not azeotropic and that the bubble curve is linear, except for the DMCA + ethanol mixture. The surface tension of the binary mixtures was modeled with linear gradient theory, parachor method, Shereshefsky method, and Lamperski method. The linear gradient theory used as adjustment approach improved the results of surface tension prediction and correctly modeled this thermodynamic property for all mixtures, the flexibility of parachor method as an adjustment approach improved the predictive results for some mixtures, Shereshefsky method was able to successfully model the surface tension of the DMCA + ethanol, DMCA + propanol, and DMCA + butanol mixtures, and Lamperski method was able to successfully model the surface tension of the DMCA + propanol and DMCA + butanol mixtures, while the DMCA + ethanol and DMCA + isobutanol mixtures had an acceptable statistical deviation. Furthermore, Lamperski method was the best predicted model to model surface tension of the binary mixtures. Based on Shereshefsky model, the standard Gibbs energy of adsorption and the free energy change in the surface region were calculated. The free energy change was used to obtain the number of molecular layers in the surface region. Also, with Shereshefsky method it was obtained that alcohol is not absorbed at the surface which was also confirmed with Lamperski method. Finally, it is important to note that phase equilibria and surface tension of the DMCA + alcohol mixtures is modeled with theoretical approaches for the first time. On the other hand, for future experimental measurements of phase equilibria, our results could serve as an initial approximation of equilibrium, and the correlations obtained for the binary parameters of the linear gradient theory and parachor method can be used to predict surface tension at other temperatures outside the range 288.15 to 308.15 K.

Thermodynamic properties and thermodynamic modelling for aqueous mixed system containing lithium metaborate and sodium metaborate

The pH values, solubilities and water activities in the system LiB(OH)4–NaB(OH)4–H2O at 323.15 K were investigated. The mole fractions of boron species were calculated in the aqueous borate solutions, and the distribution and relevant mechanism were also discussed. The solubility diagrams in the ternary system were drawn at 323.15 K. The phase diagram consists of two single salt regions for LiB(OH)4 and NaB(OH)4·2H2O, one invariant point co-saturated with the above salts. On the basis of the Pitzer model, the Pitzer binary parameters and mixing parameters were fitted with the water activities, saturated vapour pressure and solubilities in the ternary system. The dissolution equilibrium constants (Ksp) of LiB(OH)4 and NaB(OH)4·2H2O were calculated using the experimental solubility data. The calculated solubilities with the parameters and Ksp agree well with the experimental data.

The Long-term Evolution of Main-sequence Binaries in DRAGON Simulations

Abstract We present a comprehensive investigation of main-sequence binaries in the DRAGON simulations, which are the first one-million-particle direct N-body simulations of globular clusters. We analyze the orbital parameters of the binary samples in two of the DRAGON simulations, D1-R7-IMF93 and D2-R7-IMF01, focusing on their secular evolution and correlations up to 12 Gyr. These two models have different initial stellar mass functions: Kroupa 1993 (D1-R7-IMF93) and Kroupa 2001 (D2-R7-IMF01); and different initial mass-ratio distributions: random paring (D1-R7-IMF93) and a power law (D1-R7-IMF93). In general, the mass ratio of a population of binaries increases over time due to stellar evolution, which is less significant in D2-R7-IMF01. In D1-R7-IMF93, primordial binaries with a mass ratio q ≈ 0.2 are most common, and the frequency linearly declines with increasing q at all times. Dynamical binaries of both models have higher eccentricities and larger semimajor axes than primordial binaries. They are preferentially located in the inner part of the star cluster. Secular evolution of binary orbital parameters does not depend on the initial mass-ratio distribution, but is sensitive to the initial binary distribution of the system. At t = 12 Gyr, the binary fraction decreases radially outwards, and mass segregation is present. A color difference of 0.1 mag in F330W − F814W and 0.2 mag in NUV − y between the core and the outskirts of both clusters is seen, which is a reflection of the binary radial distribution and the mass segregation in the cluster. The complete set of data for primordial and dynamical binary systems at all snapshot intervals is made publicly available.

Vapour-liquid equilibria of systems containing deep eutectic solvent based on choline chloride and glycerol

Deep eutectic solvents (DES) have been recently proposed as potential entrainers for extractive distillation to obtain anhydrous ethanol. However, the lack of thermodynamic data of mixtures containing DESs still hampers studies of their application in separation processes. In this work, the DES based on choline chloride and glycerol (ChCl:G) at the molar ratio of 1:2 was proposed as extracting solvent for ethanol dehydration. Therefore, the vapour-liquid equilibrium (VLE) of the pseudo-binary systems {water - ChCl:G(1:2.000) & ethanol - ChCl:G(1:2.000)} were measured at 11.3 kPa. The pseudo-ternary VLE data of {ethanol–water-ChCl:G(1:2.000)} were also obtained, keeping the concentration of ChCl:G(1:2.000) nearly constant (x3 = 0.50). The experimental VLE data were correlated to non-random two-liquid (NRTL) and universal quasichemical (UNIQUAC) models aiming to calculate the interaction binary parameters. Through the overall average errors, it was concluded that the UNIQUAC model describes better the binary systems {ethanol - ChCl:G(1:2.000)} (0.465%) while NRTL is more suitable to describe the system {water - ChCl:G(1:2.000)} (0.113%). However, the pseudo-ternary system {ethanol – water – ChCl:G (1:2.000)} could not be successfully represented by the coefficients obtained from the binary data. In addition, the VLE results of the pseudo-ternary system demonstrated that ChCl:G(1:2.000) increased the relative volatility of ethanol–water, indicating the potential use of ChCl:G(1:2.000) in the production of anhydrous ethanol through extractive distillation.

Gravitational waves from binary black hole mergers surrounded by scalar field clouds: Numerical simulations and observational implications

We show how gravitational-wave observations of binary black hole (BBH) mergers can constrain the physical characteristics of a scalar field cloud parameterized by mass $\tilde{\mu}$ and strength $\phi_0$ that may surround them. We numerically study the inspiraling equal-mass, non-spinning BBH systems dressed in such clouds, focusing especially on the gravitational-wave signals emitted by their merger-ringdown phase. These waveforms clearly reveal that larger values of $\tilde{\mu}$ or $\phi_0$ cause bigger changes in the amplitude and frequency of the scalar-field-BBH ringdown signals. We show that the numerical waveforms of scalar-field-BBHs can be modelled as chirping sine-Gaussians, with matches in excess of 95%. This observation enables one to employ computationally expensive Bayesian studies for estimating the parameters of such binaries. Using our chirping sine-Gaussian signal model we establish that observations of BBH mergers at a distance of 450 Mpc will allow to distinguish BBHs without any scalar field from those with a field strength $\phi_0 \gtrsim 5.5\times 10^{-3}$, at any fixed value of $\tilde \mu \in [0.3,0.8]$, with 90% confidence or better, in single detectors with Advanced LIGO/Virgo type sensitivities. This provides hope for the possibility of determining or constraining the mass of ultra-light bosons with gravitational-wave observations of BBH mergers.

Modeling compact binary signals and instrumental glitches in gravitational wave data

Transient non-Gaussian noise in gravitational wave detectors, commonly referred to as glitches, pose challenges for detection and inference of the astrophysical properties of detected signals when the two are coincident in time. Current analyses aim toward modeling and subtracting the glitches from the data using a flexible, morphology-independent model in terms of sine-Gaussian wavelets before the signal source properties are inferred using templates for the compact binary signal. We present a new analysis of gravitational wave data that contain both a signal and glitches by simultaneously modeling the compact binary signal in terms of templates and the instrumental glitches using sine-Gaussian wavelets. The model for the glitches is generic and can thus be applied to a wide range of glitch morphologies without any special tuning. The simultaneous modeling of the astrophysical signal with templates allows us to efficiently separate the signal from the glitches, as we demonstrate using simulated signals injected around real O2 glitches in the two LIGO detectors. We show that our new proposed analysis can separate overlapping glitches and signals, estimate the compact binary parameters, and provide ready-to-use glitch-subtracted data for downstream inference analyses.