Binary Systems Research Articles

Tidal Love numbers from EFT of black hole perturbations with timelike scalar profile

We study static tidal Love numbers (TLNs) of a static and spherically symmetric black hole for odd-parity metric perturbations.We describe black hole perturbations using the effective field theory (EFT), formulated on an arbitrary background with a timelike scalar profile in the context of scalar-tensor theories.In particular, we obtain a static solution for the generalized Regge-Wheeler equation order by order in a modified-gravity parameter and extract the TLNs uniquely by analytic continuation of the multipole index ℓ to non-integer values.For a stealth Schwarzschild black hole, the TLNs are vanishing as in the case of Schwarzschild solution in general relativity.We also study the case of Hayward black hole as an example of non-stealth background, where we find that the TLNs are non-zero (or there is a logarithmic running).This result suggests that our EFT allows for non-vanishing TLNs and can in principle leave a detectable imprint on gravitational waves from inspiralling binary systems, which opens a new window for testing gravity in the strong-field regime.

Discovery of 226 [formula omitted] Scuti and [formula omitted] Doradus Stars near NGC 6871 with TESS

We present the discovery of 269 pulsating variable stars of δ Scuti, γ Doradus, and Maia types in the vicinity of the open cluster NGC 6871, using data from the Transiting Exoplanet Survey Satellite (TESS). Our small-scale regional survey centered on the δ Scuti star V1821 Cyg in the open cluster NGC 6871, covering a radius of one degree. The results include a remarkable total of 1512 newly classified variable stars, comprising the following categories: 105 δ Scuti stars, 121 γ Doradus stars, 50 Maia variables, 198 eclipsing binary systems, with 12 exhibiting pulsating or rotating components, 500+ rotating variable stars, and dozens of other types. Out of 1512 newly discovered variable stars, 108 are confirmed members of NGC 6871 with a membership probability exceeding 50%. Notably, dedicated Fourier analyses were applied to eight representative stars from the newly discovered variables. Among these, one star exhibits a rich and complex pulsation spectrum characterized by amplitude variations in dominant pulsations. To contextualize the new pulsators, we plotted them in the Hertzsprung–Russell diagrams alongside the largest known group of class member stars. Surprisingly, both δ Scuti and γ Doradus stars occupy nearly the same region in the diagrams, hinting at a potential unified pulsation mechanism. This study contributes valuable insights into the variability census of NGC 6871 and sheds light on the pulsation behavior of different stellar types. Further investigations into the physical properties and evolutionary status of these stars are warranted.

Asteroid pairs: Survey of the inner main belt

Context. An asteroid pair forms when an asteroid splits into two unbound fragments because of collision, rotational fission, or binary system decay. The two components of the asteroid pair share similar physical properties and their orbits converge when integrated into the past. Currently, 268 asteroid pairs are known, and new pairs are discovered alongside the continuous discovery of new asteroids. Aims. We conducted a survey in the inner asteroid belt to find new asteroid pairs, estimated their age, and classified their physical properties. As presently no M-type asteroid pairs are known, we also conducted a specialized survey of them. Methods. We preselected asteroid pair candidates based on their distances in the five-dimensional space of osculating orbital elements. We created multiple clones within the uncertainties of their orbital elements and conducted their backtrack integration into the past. We searched for convergence of their clones at close spatial points with small relative velocities, the distribution of which determines the pair formation age. Results. We find 40 new asteroid pairs, thus increasing the total number of known pairs by 15%. One of the newly discovered pairs, 469759 - 2016 QZ 123, with an age of 2.6−0.2+0.7 kyr is now the third-youngest known asteroid pair. We studied the influence of the mutual gravitation of pair components on the process of their evolution and successfully observed the gravitational catching of the two pair members in the past. As a byproduct of pair search, we find eight asteroids connected in a cluster with an age of 76−25+15 kyr that belongs to the Phocaea family and incorporates one previously known asteroid pair. We confirm the convergence of ten asteroid pairs discovered in our previous research and improve their age estimates. We observed a deficiency of M-type asteroid pairs, and therefore conducted a dedicated search for M-type pairs, but found none.

Cm(III) speciation in the presence of citrate from neutral to hyperalkaline conditions and the effect of calcium

We investigated the binary Cm-citrate system using time-resolved laser fluorescence spectroscopy (TRLFS), parallel factor analysis (PARAFAC), and quantum chemical calculations. Evidence collectively suggests the stepwise coordination and deprotonation of citrate alcohol groups in Cm-cit complexes with two bound citrate moieties upon increasing pH, which is supported by a bathochromic shift in emission spectra, an observed increase in lifetime measurements, and lower energy minima for citrate alcohol involvement versus hydrolysis of the Cm-citrate species. Our PARAFAC results agree with a 3-component model for the Cm-citrate system and offer pure component decompositions, yielding fraction species across the studied pH range that have a correlated slope = 1 as a function of pH. For the first time, evidence of ternary Ca-Cm-citrate complexes was revealed by TRLFS with increasing calcium concentration at fixed pHm. The formation of these ternary complexes was substantiated with density functional theory (DFT) calculations on simple model systems of the complexes. Shared citrate carboxylate groups between calcium and curium were proposed for all three ternary Ca-Cm-cit complexes based on DFT-determined Ca–O and Cm–O distances. Moreover, we found that the ternary complex with both alcohol groups deprotonated is most stable when it shares both two carboxylate and two alcohol groups between Ca and Cm. The presence of shared functional groups highlights the enhanced stability of these ternary complexes. Additional work is warranted to further constrain the stoichiometry, stability constants and dependence on ionic strength of these complexes for purposes of thermodynamic modeling of repository settings.

Creating a Gender-inclusive Learning Environment in Spanish Language Classrooms

Non-binary speakers often struggle to describe themselves within the binary gender system of Spanish. This is even more of a challenge for learners of Spanish who are used to describing themselves in English without having to identify their gender. Our study investigates how we can create a more inclusive learning experience in our Spanish language classrooms. To answer our research question, we conducted a needs analysis through the distribution of an online survey and a series of 20-minute interviews with students and instructors of Spanish in Western Canada. Through these methods, we determined what participants already know about gender-neutral and inclusive language, and what they want or need to know to be able to use and teach inclusive language. Participants were also given the opportunity to share their suggestions and ideas as to how to create a more inclusive learning environment. The key findings indicated that both instructors and students need education and training, and access to teaching and learning resources to normalize the use of gender-inclusive language in the Spanish classroom, which in return will help foster a learning space that is inclusive of all students.

Organo magadiites for diclofenac adsorption: influence of the surfactant chain.

The presence of drugs in aquatic environments has been considered a global challenge and several remediation technologies have been proposed, including adsorption. In this study, new diclofenac adsorbents were obtained from the reaction of sodium magadiite (Na-Mag) with surfactants dodecylpyridinium chloride hydrate (C12pyCl) and hexadecylpyridinium chloride monohydrate (C16pyCl)), 1-hexadecyltrimethylammonium bromide (C16Br), and dodecyltrimethylammonium bromide (C12Br). The synthesis was carried out in the microwave at 50°C for 5min using surfactant amounts of 100% and 200% in relation to the cation exchange capacity of Na-Mag. The elemental analysis indicated that surfactants with a longer organic chain were more incorporated into Na-Mag, whose values were 1.42 and 1.32mmolg-1 for C16pyMag200% and C16Mag200%, respectively. X-ray diffraction results suggested formation of intercalated products with basal space in the range of 2.81-4.00nm. Diclofenac was quickly adsorbed on all organophilic magadiites, at an equilibrium time of 1min. Drug capacity adsorption was influenced by the arrangement and packing density of organic cations, the basal distance, and the organic contents of the samples at high drug concentrations. Alkylpyridinium magadiites exhibited maximum adsorption capacities higher than alkylammonium magadiites, of 96.4, 100.7, 131.7, and 166.1mgg-1 for C12pyMag100%, C12pyMag200%, C16pyMag100%, and C16pyMag200%, respectively, at pH 6.0 and 30°C. Diclofenac removal by samples was not affected by the presence of ibuprofen, which was also removed from binary system by organophilic magadiites reaching removal of 76.5% and 86.9% by C16pyMag100% and C16pyMag200%, respectively. Regeneration studies demonstrated a drug removal percentage of 83-92% for C16pyMag and C16Mag after three cycles of adsorption.

Efficient co-removal of aqueous Cr(VI) and ciprofloxacin by alkali lignin-derived carbon supported nanoscale zero-valent iron via adsorption and redox synergistic mechanisms

Developing an efficient co-removal strategy is crucial for the treatment of combined contaminants with heavy metals and antibiotics due to their great threat to sustainable advancement and ecological preservation. Herein, the efficient co-removal of aqueous hexavalent chromium (Cr(VI)) and ciprofloxacin (CIP) is achieved via a newly developed composite of nanoscale zero-valent iron particles embedded into alkali lignin-derived carbon (nZVI/ALC) without external assistance (such as light, advanced oxidants). nZVl/ALC demonstrates superior co-removal efficiencies of Cr(VI) (99.9 %) and CIP (89.9 %) with high removal kinetic rate constants of 1.595 and 0.779 min−1, respectively. The underlying mechanisms involving the co-removal of Cr(VI) and CIP verify that Cr(VI) ions are adsorbed onto the skeleton of nZVI/ALC originating from the electrostatic interaction, and CIP molecules adsorbed on nZVl/ALC act as a bridge, complexing with the Cr(VI) ions to promote Cr(VI) removal. Meanwhile, the CIP adsorption by nZVI/ALC involves hydrogen bonding, π-π interaction, and complexation. The coexisting Cr(VI) ions are transformed into Cr(III) components with abundant electron transfer, leading to the generation of more •O2– radicals, thus the self-generating reactive oxygen species (•OH, •O2– and 1O2) in ambient-air condition promote CIP degradation in the binary system. The CIP molecules’ degradation pathways mainly include piperazine ring cracking, piperazine epoxidation, quinolone ring opening and defluorination according to the analysis of HPLC-MS and FuKui function, along with the gradual reduction in toxicity throughout the degradation process of CIP molecules. This study offers a new insight on the co-removal of Cr(VI) and CIP, which would provide promising guidance for the remediation of compound wastewater with heavy metals and antibiotics.

Myocardial Ischemic Syndromes: A New Nomenclature to Harmonize Evolving International Clinical Practice Guidelines.

Since the 1960s, cardiologists have adopted several binary classification systems for acute myocardial infarction (MI) that facilitated improved patient management. Conversely, for chronic stable manifestations of myocardial ischemia, various classifications have emerged over time, often with conflicting terminology-eg, "stable coronary artery disease" (CAD), "stable ischemic heart disease," and "chronic coronary syndromes" (CCS). While the 2019 European guidelines introduced CCS to impart symmetry with "acute coronary syndromes" (ACS), the 2023 American guidelines endorsed the alternative term "chronic coronary disease." An unintended consequence of these competing classifications is perpetuation of the restrictive terms "coronary" and 'disease', often connoting only a singular obstructive CAD mechanism. It is now important to advance a more broadly inclusive terminology for both obstructive and non-obstructive causes of angina and myocardial ischemia that fosters conceptual clarity and unifies dyssynchronous nomenclatures across guidelines. We, therefore, propose a new binary classification of "acute myocardial ischemic syndromes" and "non-acute myocardial ischemic syndromes," which comprises both obstructive epicardial and non-obstructive pathogenetic mechanisms, including microvascular dysfunction, vasospastic disorders, and non-coronary causes. We herein retain accepted categories of ACS, ST-segment elevation MI, and non-ST segment elevation MI, as important subsets for which revascularization is of proven clinical benefit, as well as new terms like ischemia and MI with non-obstructive coronary arteries. Overall, such a more encompassing nomenclature better aligns, unifies, and harmonizes different pathophysiologic causes of myocardial ischemia and should result in more refined diagnostic and therapeutic approaches targeted to the multiple pathobiological precipitants of angina pectoris, ischemia, and infarction.

Delayed Emission from Luminous Blue Optical Transients in Black Hole Binary Systems

At least three members of the recently identified class of fast luminous blue optical transients show evidence of late-time electromagnetic activity in great excess of what was predicted by an extrapolation of the early time emission. In particular, AT2022tsd displays fast, bright optical fluctuations approximately a month after the initial detection. Here we propose that these transients are produced by exploding stars in black hole binary systems and that the late-time activity is due to the accretion of clumpy ejecta onto the companion black hole. We derive the energetics and timescales involved, compute the emission spectrum, and discuss whether the ensuing emission is diffused or not in the remnant. We find that this model can explain the observed range of behaviors for reasonable ranges of the orbital separation and the ejecta velocity and clumpiness. Close separation and clumpy, high-velocity ejecta result in bright variable emission, as seen in AT2022tsd. A wider separation and smaller ejecta velocity, conversely, give rise to fairly constant emission at a lower luminosity. We suggest that high-cadence, simultaneous, panchromatic monitoring of future transients should be carried out to better understand the origin of the late emission and the role of binarity in the diversity of explosive stellar transients.

Adiabatic Mass Loss in Binary Stars. IV. Low- and Intermediate-mass Helium Binary Stars

The unstable mass transfer situation in binary systems will asymptotically cause the adiabatic expansion of the donor star and finally lead to the common envelope phase. This process could happen in helium binary systems once the helium donor star fills its Roche-lobe. We have calculated the adiabatic mass-loss model of naked helium stars with a mass range of 0.35 M ⊙–10 M ⊙, and every mass sequence evolved from the helium-zero-age main sequence to the cooling track of white dwarf or carbon ignition. In consideration of the influence of stellar wind, massive helium stars are not considered in this paper. Comparing the stellar radius with the evolution of the Roche-lobe under the assumption of conservative mass transfer, we give the critical mass ratio q crit = M He/M accretor as the binary stability criteria of low- and intermediate-mass helium binary stars. On the helium main sequence, the result shows 1.0 < q crit < 2.6, which is more unstable than the classical result of polytropic model q crit = 3. After the early helium Hertzsprung Gap, the q crit quickly increases even larger than 10 (more stable compared with the widely used result of q crit = 4), which is dominated by the expansion of the radiative envelope. Our result could be useful for these quick mass transfer binary systems such as AM CVns, ultra-compact X-ray binaries, and helium novae, and it could guide the binary population synthesis for the formation of special objects such as type Ia supernova and gravitational wave sources.

Charge-dependent CALPHAD analysis of defect chemistry and carrier concentration for space charge layers

The development of conductive materials plays a crucial role in improving the efficiency of electrochemical processes. In polycrystalline materials, space charge layers (SCLs) adjacent to grain boundaries (GBs) often dictate charge transport behavior. This study explores relaxing the charge neutrality constraint in the CALculation of PHAse Diagrams (CALPHAD) approach as a new method to model the electrical conductivity effects of SCLs. A new charge-dependent defect chemistry analysis is applied to the wustite, magnetite, and hematite phases in the Fe–O binary system. Using pycalphad, charge-dependent results for the molar Gibbs energies, Brouwer diagrams, and charge carrier concentrations were determined for each phase at 1273K within the oxygen partial pressure stability ranges. With a negative charge of 0.16 × 10−19 C, the hematite and magnetite phases exhibit an increased charge carrier concentration. The opposite trend was observed for wustite. While further work is needed to quantify the electrical conductivity effects of the SCLs and GBs with this approach, it provides a robust thermodynamic foundation to rapidly develop and optimize conductive materials.

Detection of Two Totally Eclipsing B-type Binaries with Extremely Low Mass Ratios

The detection of O- and B-type stars with extremely low-mass companions is very important for understanding the formation and evolution of binary stars. However, finding them remains a challenge because the low-mass components in such systems contribute such small flux to the total. During our search for pulsations among O- and B-type stars using the Transiting Exoplanet Survey Satellite (TESS) data, we found two short-period and B-type (B9) eclipsing binaries with orbital periods of 1.61613 and 2.37857 days. Photometric solutions of the two close binaries were derived by analyzing the TESS light curves with the Wilson–Devinney method. It is discovered that both of them are detached binaries with extremely low mass ratios of 0.067(2) for TIC 260342097 and 0.140(3) for TIC 209148631. The determined mass ratio indicates that TIC 260342097 is one of the lowest mass ratios among known B-type binary systems. We showed that the two systems have total eclipses with a broad and flat secondary minimum, suggesting that the photometric parameters could be derived reliably. The absolute parameters of the two binaries are estimated and it is found that the secondary components in the two systems are overluminous and oversize when compared with the normal low-mass and cool main-sequence (MS) stars. These findings may imply that the two systems are composed of a B-type MS primary and a cool pre-MS secondary with orbital periods shorter than 2.5 days. They are valuable targets to test theories of binary star formation and evolution.

Structural, morphological, and magnetic properties of carbon-modified nanocrystalline Pr5Co19 alloys

Nanocrystalline rare-earth (R) and transition metal (T) alloys are known for their outstanding magnetic properties, which are driven by the combination of (R) and (T) magnetic moments. Adding carbon (C) has been proven to alter these magnetic properties. In the present work, we use X-ray diffraction, transmission electron microscopy, and atom probe tomography to investigate and characterize the impact of carbon addition on the crystalline structure, morphology, and chemical distribution of Pr5Co19 and its carbides Pr5Co19Cx. The nanocrystalline Pr5Co19 compound was synthesized by high-energy ball milling and the addition of carbon was performed by a solid-solid reaction between Pr5Co19 and C10H14. TEM study revealed that after carbonation the microstructure is refined, and the mean grain size decreases from 126 nm in Pr5Co19 to 65 nm with a carbon of content 1.5. Three-dimensional APT was performed to characterize the chemical composition of Pr-Co binary systems. The analyzed Pr5Co19C1.5 sample reveals an irregular nano-lamella structure decorated by carbon atoms, the distance between the lamellas varying from 8 to 20 nm. An under-stoichiometry of Co was found in the C-rich lamellas. Fundamental magnetic properties such as saturation magnetization Ms, exchange field Hex and magnetic susceptibility χ of the Pr5Co19 and its carbides were calculated using the random magnetic anisotropy (RMA) method.

Enhanced removal of acidic dyes (AB1 and MO) from binary systems using anion exchange membrane BII: kinetic, isotherm, and thermodynamic analyses.

In the current work, the adsorption of acid black 1 (AB1), a hair dye, and methyl orange (MO) on anion exchange membrane BII (AEM-BII) in a binary system was studied experimentally. The effects study for contact time, adsorbent's and adsorbates' concentration, and temperature of aqueous media on the AB1 and MO removal, AEM-BII recovery, and reusability were also investigated. The highest removal was observed at optimum conditions, 150-min contact time and 5g L-1 of adsorbent for AB1 (91.2%) and MO (83.4%). Adsorption kinetics was estimated by pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetics. The experimental findings were fitted well by PSO kinetics with an adsorption capacity of 19.45 ± 0.93 and 19.34 ± 0.84mgg-1 for ABI and MO, respectively. Moreover, the adsorption isotherm study confirmed that AB1 and MO adsorption by AEM-BII from the binary system was followed by Langmuir isotherms. Adsorption thermodynamics revealed that adsorption of both AB1 and MO by AEM-BII was endothermic and spontaneous. Moreover, the desorption phenomenon of ABI and MO from the loaded AEM-BII showed that dye removal from AEM-BII was found to be 74.95%, demonstrating AEM-BII can be considered as good adsorbent for acidic dyes from the binary system.

Binary solvent-reinforced poly (vinyl alcohol)/sodium alginate double network hydrogel as a highly ion-conducting, resilient, and self-healing gel polymer electrolyte for flexible supercapacitors

We present a reliable approach for producing high-performance ion-conducting gel polymer electrolytes (GPEs) based on the sodium chloride (NaCl)-integrated dual network hydrogel of poly (vinyl alcohol)/sodium alginate (PVA/SA) using a binary solvent system of ethylene glycol (EG) and water, providing exceptional ionic conductivity, mechanical strength, and self-healing properties. Different GPEs were produced via the freezing-thawing method using different v/v% of EG and water (named PVA/SA/EG). The best PVA/SA/EG GPE provided a maximum ionic conductivity of 25 mS cm−1, astonishing mechanical strength of 0.42 MPa, exceptional stretchability of 462 %, and remarkable self-healing properties. The binary solvent system- and water-based GPEs were utilized in the construction of symmetric supercapacitors (SSCs) using carbon cloth electrodes and their electrochemical performance were compared. At a current density of 0.5 mA cm−2, the SSC prepared using the best PVA/SA/EG GPE demonstrated a high specific capacity of 577.21 mF cm−2, maintained 94.5 % capacitance after 5000 cycles at 1 mA cm−2, and provided an energy density of 80.14 mWh cm−2 while operating at a power density of 293.3 mW cm−2. The flexible SSC prepared based on this GPE demonstrated outstanding flexibility, while no significant decline in capacitive performance and ionic conductivity was detected when it was bent.

A facile and effective strategy for modifying combustion of Zr/KClO4 via adding Si

As a commonly applied ignition composition, Zr/KClO4 has attracted various interests and plenty of efforts have been made to improve the combustion performance. In this study, Si nanoparticles were incorporated into Zr/KClO4 by sonication. Around 2.5× peak pressure and 9.2× reactivity were achieved by Si/50%Zr/KClO4 when compared to Zr/KClO4. In addition, the peak pressure and pressurization rate of Si/Zr/KClO4 ternary systems are all superior to ones of both Zr/KClO4 and Si/KClO4 binary systems. The synergetic effect of Si/Zr/KClO4 is a combination of shorter ignition delay of Zr/KClO4 and more gas production of Si/KClO4, which is also reflected on the higher flame propagation rate of Si/Zr-based thermites than composites with pure Si or Zr as the fuel. Meanwhile, the heat release during the redox reaction has been measured. The results show ∼700–1000 J/g higher energy release than Zr/KClO4, and higher combustion efficiency can be attained by ternary systems than binary ones. Thus, adding Si powders is an effective way to improve the energetic behavior of Zr/KClO4 ignition composition, and Si/Zr/KClO4 ternary composites can be a promising candidate for application in pyrotechnics.

A New Puzzling Periodic Signal in GeV Energies of the γ-Ray Binary LS I+61°303

LS I+61°303 is a high-mass X-ray binary system comprising a massive Be star and a rapidly rotating neutron star. Its spectral energy distribution across multiwavelengths categorizes it as a γ-ray binary system. In our analysis of LS I+61°303 using Fermi Large Area Telescope observations, we not only confirmed the three previously discussed periodicities of orbital, superorbital, and orbital–superorbital beat periods observed in multiwavelength observations, but also identified an additional periodic signal. This newly discovered signal exhibits a period of ∼26.3 days at a ∼7σ confidence level. Moreover, the power spectrum peak of the new signal gradually decreases as the energy increases across the energy ranges of 0.1–0.3, 0.3–1.0, and 1.0–500.0 GeV. Interestingly, a potential signal with a similar period was found in data obtained from the Owens Valley Radio Observatory 40 m telescope. We suggest that the newly discovered periodic signal may originate from a coupling between the orbital period and the retrograde stellar precession period.

Chemistry and relevant thermophysical properties of Pb84.3Li15.7 liquid solutions: Updated view and identification of new and coherent values

The liquid breeding blanket concept of a fusion reactor is based on the employment of the eutectic Lead-Lithium solution (LLE), where Lithium, enriched in 6Li, has the purpose of regenerating Tritium by reacting with neutrons, while Lead enhances the process acting as neutrons multiplier. Anyway, despite the huge interest on this binary system, LLE is not characterized yet by a fully consolidated description of its basic thermophysical properties and, in many cases, the spread of values reported so far in literature remains still significant. The purpose of this paper is hence to check again the many data available in literature, with a special attention to the ones more recently published, trying to explain and solve their inhomogeneity. Taking into account the general features of the Pb-Li interaction and particularly the not ideal behaviour of the Pb-Li liquid solutions, the following thermophysical properties of the LLE are dealt in detail: specific heat; density and volumetric thermal expansion coefficient; thermal conductivity and diffusivity; electrical resistivity; Sieverts' constant of Hydrogen. Based on the deep analysis of all the reported experimentation and through the adoption of several comparison criteria, the most trustable correlation is sought for each of the above properties; additionally, when a robust correlation couldn't be retrieved, a new, optimized, one has been proposed, capable also to foresee correctly the effect of small composition variations and to assure the internal coherence among linked properties.Specific heat and density values resulted at the end accurately described and not needing for additional experimentation; thermal properties and electrical resistivity can be evaluated with decent confidence, even if their uncertainty could be somehow reduced by future investigations; for Sieverts' constant it has not possible yet to identify a unique, trustable correlation, anyway the range of values correctly assumed up to 900K has been significantly restricted.

The Completeness of Accreting Neutron Star Binary Candidates from the Chinese Space Station Telescope

Abstract A neutron star (NS) has many extreme physical conditions, and one may obtain some important information about an NS via accreting neutron star binary (ANSB) systems. The upcoming Chinese Space Station Telescope (CSST) provides an opportunity to search for a large sample of ANSB candidates. Our goal is to check the completeness of the potential ANSB samples from CSST data. In this paper, we generate some ANSBs and normal binaries under the CSST photometric system by binary evolution and binary population synthesis method and use a machine learning method to train a classification model. Although the Precision (94.56%) of our machine learning model is as high as before study, the Recall is only about 63.29%. The Precision/Recall is mainly determined by the mass transfer rate between the NSs and their companions. In addition, we also find that the completeness of ANSB samples from CSST photometric data by the machine learning method also depends on the companion mass and the age of the system. ANSB candidates with a low initial mass companion star (0.1 M ⊙ to 1 M ⊙) have a relatively high Precision (94.94%) and high Recall (86.32%), whereas ANSB candidates with a higher initial mass companion star (1.1 M ⊙ to 3 M ⊙) have similar Precision (93.88%) and quite low Recall (42.67%). Our results indicate that although the machine learning method may obtain a relatively pure sample of ANSBs, a completeness correction is necessary for one to obtain a complete sample.

Axion Halo around a Binary System of Dwarf Stars

The gravitational field of a clump of ultralight axion like particles (ALPs) in its core with a rotating binary system of dwarf stars is computed. It is established that the induced quadrupole mass moment of the clump is controlled parametrically by the Ma/M mass ratio of the axion clump and the binary core.