arXiv subjects

Sufen Guo

Publications and source records attributed to Sufen Guo.

At least 19 recordsLinked to original sources

arXiv2026

First double red giant Algol system with active mass transfer

Double red giant stars are very important for studies of the stability of mass transfer, common-envelope evolution, and the formation of double white dwarfs with short orbital periods. However, no double red giant system undergoing mass transfer has yet been found. We present the discovery of a close Algol-type binary system composed of two red giant stars. This is the first known semi-detached system observed during the very short phase when the accretor has expanded into a red giant just before entering the common envelope phase. The $H_\alpha$ line suggests that the system has recently lost some material, which is now moving toward us. We present a consistent analysis of all the available spectroscopic and photometric observations of this system, constraining its orbital parameters and the fundamental properties of the components. Our findings are supported by a binary evolution model that successfully reproduces the currently observed parameters. The model suggests that the system will eventually merge into a single star.

astro-ph.SR↗

arXiv2026

A Possible Triple Formation Scenario of Binary Black Hole Merge With One In Pair-instability Supernova Mass Gap

Observations of binary black hole (BBH) mergers detected by LIGO -- such as GW170729, GW190620, GW190706, GW230107, GW230820, and GW230928 -- feature high effective spins and primary black holes that fall squarely into the pair-instability supernova (PISN) mass gap ($\sim 45-130 \, M_{\odot}$). These events pose a significant challenge to standard stellar and binary evolution theories. To address this, we propose an isolated hierarchical triple stellar evolution channel. In this framework, tidal synchronization in tight inner binaries drives chemically homogeneous evolution (CHE), entirely bypassing giant expansion. A subsequent triple common envelope (TCE) evolution, triggered by the tertiary companion, rapidly drives the inner BBH to coalescence. Our model can provide a detailed evolutionary pathway that elegantly reproduces the properties of these GWs, such as GW190706. Assuming a low-metallicity environment ($Z = 0.001$), our framework predicts a volumetric merger rate of approximately $0.011 \, \mathrm{Gpc}^{-3}\mathrm{yr}^{-1}$ at $z \approx 0.68$, accounting for $22\%$ of the empirical rate for this mass regime in the GWTC-4 catalog. This study demonstrates that primordial triple interactions are a highly efficient avenue for populating the PISN mass gap.

astro-ph.HE↗

arXiv2026

Testing the cosmological principle with quasars

The inferred velocity is consistent at the 1.56 {\sigma} level with the value of 370 km/s from a purely kinematic interpretation of the CMB dipole. Based on the motion direction component analysis, we have not found any significant deviation from cosmological principle in current released quasars data. The cosmological principle posits that the universe is homogeneous and isotropic on the large scales. In history, the cosmological principle was confirmed by various cosmological observations from CMB to large scale structure. However, several new challenges to the cosmological principle were reported in recent years, particularly in radio observations from overdispersed radio source counts to quasars. Here, we firstly present studies on the peculiar velocity of large-scale anisotropy by measuring the dipole signal from the DESI DR1 catalogue with a sample of 1,176,570 quasars (0.8 < z < 3.0). Our analysis reveals the peculiar velocity of $|v| = 443.8 \pm 204.1$ km/s towards $(l, b) = (107.4^\circ \pm 86.8^\circ, 28.4^\circ \pm 45.2^\circ)$ in Galactic coordinates.The motion direction deviates from the CMB dipole (264.02$^\circ$, 48.253$^\circ$). The inferred velocity is consistent at the 1.56 $\sigma$ level with the value of 370 km/s from a purely kinematic interpretation of the CMB dipole. Based on the motion direction component analysis, we have not found any significant deviation from cosmological principle in current released quasars data.

astro-ph.CO↗

arXiv2026

Mass distribution of neutron stars in binary systems

It is known that the mass distribution of the known neutron stars (NSs) exhibits a bimodal pattern. The origin of this distribution remains a subject of debate. We constructed a super-Eddington accretion model for accreting neutron stars and investigated the mass growth and distribution of these stars using the population synthesis method. We find, in our model, the mass growth of NSs depends on the binary orbital period and the mass of the donor star. Our results can successfully account for the bimodal distribution of NS masses. The peak distribution of NS masses at around ~ 1.8 Msun primarily originates from NS binary systems where the donor star mass is less than ~ 1.6 Msun and the orbital period is shorter than 20 days; while, NS systems that may undergo common envelope evolution and these NSs can account for the mass peak at 1.4 Msun.

astro-ph.SR↗

arXiv2026

Astrometric properties of reference frame sources as a function of redshift

Previous studies based on the latest realisation of the International Celestial Reference Frame (ICRF3) have suggested a correlation between astrometric properties (such as the radio-optical offset) and redshift for active galactic nuclei (AGNs). We extend these investigations by using a large, all-sky sample of approximately 22,000 compact radio sources from the Radio Fundamental Catalogue (RFC) to examine this relationship in a systematic and statistically robust manner. We compiled redshifts for about 10,000 RFC sources over the range 0 < z < 5 by combining data from the Dark Energy Spectroscopic Instrument Data Release 1 and the Sloan Digital Sky Survey Data Release 17/19 with additional datasets from the NASA/IPAC Extragalactic Database. Cross-matching with Gaia Data Release 3 yielded a sample of 4,068 RFC objects with reliable spectroscopic redshifts and classifications, including galaxies and quasi-stellar objects (QSOs). We analysed the redshift dependence of their radio astrometric properties from very long baseline interferometry (VLBI) and their optical astrometric properties from Gaia. We find that the VLBI astrometric properties show no significant dependence on redshift within the achieved level of precision. In contrast, several optical astrometric quantities exhibit clear redshift-dependent behaviour. The median absolute radio-optical offsets decrease markedly over 0 < z < 0.5, where galaxies dominate the sample, decline more gradually over 0.5 < z < 1.3, and exhibit a mild increase at z > 1.3, where QSOs dominate. Similar behaviour is observed for several Gaia astrometric quantities, including astrometric uncertainties, proper motions, and G magnitudes. These behaviours can be largely explained by the dependence of Gaia astrometric performance on G magnitude and by the evolution of the G magnitude with redshift.

astro-ph.IM↗

arXiv2026

Evolution of cataclysmic variables under different magnetic braking prescriptions

Context. The evolution of cataclysmic variables (CVs) - interacting binaries where a low-mass donor transfers matter to a white dwarf via an accretion disk - is critically controlled by magnetic braking (MB). Significant uncertainties persist regarding how distinct MB formalisms influence CV evolutionary pathways. Aims. We performed systematic simulations of CV evolution under five MB prescriptions using the MESA code: the classical Skumanich law and the Matt, Reiners & Mohanty (RM12), intermediate, and convection-boosted formalisms. Primary objectives included investigating their impact on orbital period distributions, mass-transfer rates, donor star evolution, and period gap characteristics. Methods. Evolutionary sequences were computed across all MB frameworks. We analyzed their effects on key observables: orbital period evolution, accretion rates, and period gap morphology. Results. Magnetic braking prescription selection fundamentally determines whether CV systems develop the characteristic period gap. The intermediate prescription provides optimal consistency with observations of nonmagnetic CVs, simultaneously reproducing the gap location and donor properties. Strong braking models (e.g., Skumanich) produce clear detachment phases, while self-consistent regulation models (Matt12 and RM12) maintain weak angular momentum loss and fail to form a gap, making them more prone to magnetic CVs. Conclusions. The presence or absence of the period gap is primarily governed by the strength and behavior of MB before the donor becomes fully convective. Future studies must further incorporate the regulatory effects of magnetic fields on donor structure to accurately predict the period distribution characteristics of magnetic CVs.

astro-ph.SR↗

arXiv2025

Formation of the Dormant Black Holes with Luminous Companions from Binary or Triple Systems

Recently, a class of dormant black hole binaries with luminous companions (dBH-LC) has been observed, such as $Gaia$ BH1, BH2, and BH3. Unlike previously discovered X-ray BH binaries, this type of dBH-LC has relatively long orbital periods (typically more than several tens to a few hundred days) and shows very weak X-ray emission. Therefore, studying the formation and evolution of the whole dBH-LC population is also a very interesting problem. Our aim is to study the contribution of massive stars to the dBH-LC population under different evolutionary models (isolated binary evolution (IBE) and hierarchical triple evolution), and different formation channels (such as mass transfer, common envelope evolution). Using the Massive Objects in Binary Stellar Evolution (MOBSE) code, the Triple Stellar Evolution (TSE) code, and the latest initial multiple-star distributions, we model the populations of massive stars. Finally, we calculate the orbital properties, mass distributions, and birthrates of the BH-LC populations formed under these different conditions. In the Milky Way, we calculate that the birthrate of dBH-LC formed through IBE is about 4.35$\times$$10^{-5}$ ${\rm yr}^{-1}$, while the birthrate through triple evolution is about 1.47$\times$$10^{-3}$ ${\rm yr}^{-1}$. This means that the birthrate from triple evolution is one to two orders of magnitude higher than that from IBE. We find that in triple evolution, the main formation channel of dBH-LC is post-merger binaries formed from inner binary mergers triggered by von Zeipel$-$Lidov$-$Kozai oscillations.

astro-ph.SR↗

arXiv2025

Explanation of the Mass Distribution of Binary Black Hole Mergers

Gravitational wave detectors are observing an increasing number of binary black hole (BBH) mergers, revealing a bimodal mass distribution of BBHs, which hints at diverse formation histories for these systems. Using the rapid binary population synthesis code MOBSE, we simulate a series of population synthesis models that include chemically homogeneous evolution (CHE). By considering metallicity-specific star formation and selection effects, we compare the intrinsic merger rates and detection rates of each model with observations. We find that the observed peaks in the mass distribution of merging BBHs at the low-mass end (10\msun) and the high-mass end (35\msun) are contributed by the common envelope channel or stable mass transfer channel (depending on the stability criteria for mass transfer) and the CHE channel, respectively, in our model. The merger rates and detection rates predicted by our model exhibit significant sensitivity to the choice of physical parameters. Different models predict merger rates ranging from 15.4 to $96.7\,\rm{Gpc^{-3}yr^{-1}}$ at redshift $z$ = 0.2, and detection rates ranging from 22.2 to 148.3$\mathrm{yr^{-1}}$ under the assumption of a detectable redshift range of $z \le$ 1.0.

astro-ph.HE↗

arXiv2025

The influence of rotation and metallicity on the explodability of massive stars

During the late stages of massive stellar evolution, failed supernovae (FSN) may form through core-collapse processes. The traditional evaluation criterion $ξ_{2.5}$ $=$ 0.45, primarily established using non-rotating progenitor models, suffers from significant inaccuracies when applied to rotating pre-supernova systems. The effects of metallicity and rotation on the explodability landscapes of massive stars lack robust quantification. We aim to investigate how rotation and metallicity influence the explodability of massive stars. We investigate how rotation and metallicity affect stellar explodability using MESA simulations with initial rotational velocities of $0$, $300$, and $600~\mathrm{km,s^{-1}}$ at three metallicities ($Z_{\odot}$, $1/10,Z_{\odot}$, $1/50,Z_{\odot}$). Core-collapse phases are simulated with GR1D to determine critical heating efficiencies. Our results yield revised $ξ_{2.5}$ criteria: 0.45 for non-rotating models; 0.48 for $300~\mathrm{km,s^{-1}}$; 0.47 for $600~\mathrm{km,s^{-1}}$ at solar metallicity; and 0.59 for low-metallicity models. Chemically homogeneous evolution in rapidly rotating low-metallicity stars significantly raises the compactness limit for successful explosions and narrows the zero-age main sequence mass range for failed supernovae. Rotation substantially affects the explodability of low-metallicity massive stars, underscoring the importance of incorporating rotational effects in models of core-collapse supernova progenitors.

astro-ph.SR↗

arXiv2025

New symbiotic stars or candidates in LAMOST low resolution spectra

Symbiotic stars are among the most crucial binary systems for studying binary star interactions and Type Ia supernova progenitors. Based on the unique observational characteristics of symbiotic stars, strong H I, He I emission lines, giant spectral features, and the presence of [O III], He II, O VI, and other emission lines with ionization potentials exceeding 35 eV, and the Gaia information, we search for new symbiotic stars using the low-resolution spectroscopic survey data from LAMOST. Thirty-six binary systems have been selected as symbiotic stars or candidates, in which the five known symbiotic stars are included. Among them five systems (ZTF J005917.52+315605.4, ATO J094137.5+075304, LAMOST J200310.90+360822.6, LAMOST J072528.18+342530.4, and V* V758 Cyg) have been found as new symbiotic stars. Notably, LAMOST J072528.18+342530.4 and V* V758 Cyg were also confirmed as new symbiotic stars in a recent study. For the remaining 26 candidates, classification is based solely on the presence of [O III] emission lines (with ionization potentials > 35 eV) and the absence of He II high-excitation emission lines. Further observations are needed to confirm their nature as symbiotic stars.

astro-ph.SR↗

arXiv2025

The mixing of internal gravity waves and lithium production in intermediate-mass AGB stars

Context: Intermediate-mass asymptotic giant branch (AGB) stars influence Galactic lithium evolution by ejecting surface material (including Li) via stellar winds. Internal gravity waves (IGW), excited by convective motions, drive turbulent mixing in non-convective regions, altering stellar surface and wind chemistry. Aims: Investigate IGW-induced extra-mixing in the radiative zone between thermal pulses and convective envelopes of AGB stars and its impact on Li production. Derive the total Li contribution from intermediate-mass AGB stars using stellar models and initial mass functions. Methods: Construct stellar models (from zero-age main sequence to AGB end) with MESA, incorporating IGW-induced mixing and element diffusion. Calculate Li yields for stars of varying masses and metallicities using grids and population synthesis. Results: IGW triggers extra-mixing during He-shell flashes, transporting Be-7 from the radiative zone to the convective envelope, where it decays into Li-7. The positive effect of IGW on Li yield decreases with initial stellar mass but increases with metallicity. Most AGB stars (3.5-7.5 solar masses) produce positive Li yields. The total Li yield with IGW mixing (approximately 15 solar masses) is twice that without, contributing about 10 percent to Galactic Li. Conclusions: Through this extra-mixing mechanism induced by IGW, AGB stars can achieve a maximum A(Li) exceeding 5 and intermediate-mass AGB stars significantly contribute to Li in the Galactic ISM. These findings underscore the crucial role of IGW in stellar evolution, particularly in enhancing Li production.

astro-ph.SR↗

arXiv2025

The new compact triple system: discovery of bright third star around contact binary using LAMOST-MRS spectra and photometry

We present a study of the third star orbiting around known contact eclipsing binary J04+25 using spectra from the LAMOST medium-resolution survey (MRS) and publicly available photometry. This is a rare case of a hierarchical triple, where the third star is significantly brighter than the inner contact subsystem. We successfully extracted radial velocities for all three components, using the binary spectral model in two steps. Third star radial velocities have high precision and allow direct fitting of the orbit. The low precision of radial velocity measurements in the contact system is compensated by large number statistics. We employed a template matching technique for light curves to find periodic variation due to the light time travel effect (LTTE) using several photometric datasets. Joint fit of third star radial velocities and LTTE allowed us to get a consistent orbital solution with $P_3=941.40\pm0.03$ day and $e_3=0.059\pm0.007$. We made estimations of the masses $M_{\rm 12,~3}\sin^3{i_3}=1.05\pm0.02,~0.90\pm0.02~M_\odot$ in a wide system and discussed possible determination of an astrometric orbit in the future data release of Gaia. Additionally, we propose an empirical method for measuring a period and minimal mass of contact systems, based on variation of the projected rotational velocity ($V\sin{i}$) from the spectra.

astro-ph.SR↗

arXiv2025

Orbital Parameters of 665 Double-lined Spectroscopic Binaries in the LAMOST Medium-Resolution Survey

The period, mass ratio, eccentricity, and other orbital parameters are fundamental for investigating binary star evolution. However, the number of binaries with known orbital parameters remains limited. Utilizing the LAMOST-MRS survey, we derived orbital solutions for 665 SB2 binaries by fitting the radial velocities of 1119 SB2 systems with at least six observations, employing a modified version of Thejoker optimized for SB2 binaries. To ensure the reliability of the results, four selection criteria were applied: reduced chi-square, normalized mean absolute error, maximum phase gap, and RV distribution metric. After applying these criteria, 665 reliable orbits were retained. Comparison with Kepler, TESS, and ZTF light curve data shows excellent agreement, with discrepancies in some cases attributed to shorter pulsation periods observed in light curves. Additionally, good consistency is found between our periods and those of SB1 systems in Gaia data. These orbital solutions contribute to understanding binary star evolution and the statistical properties of binary populations.

astro-ph.SR↗

arXiv2025

The Impact of Neutrino Magnetic Moments on the Evolution of the Helium Flash and Lithium-Rich Red Clump Stars

The detection of the neutrino magnetic moment (NMM,$μ_v$) is one of the most significant challenges in physics. The additional energy loss due to NMM can significantly influence the He flash evolution in low-mass stars. Using the MESA code, we investigated the impact of NMM on the He flash evolution in low-mass stars. We found that NMM leads to an increase in both the critical He core mass required for the He flash and the luminosity of TRGB. For a typical $Z = 1 Z_{\odot}$ , $M$ = 1.0 $M_{\odot}$, and $μ_v = 3 \times 10^{-12} μ_{\mathrm{B}}$ model, the He core mass increases by $\sim 5\%$, and the TRGB luminosity increases by $\sim 35\%$ compared to the model without NMM. However, contrary to previous conclusions, our model indicates that the He flash occurs earlier, rather than delayed, with increasing NMM values. This is because the additional energy loss from NMM accelerates the contraction of the He core, releases more gravitational energy that heats the H shell and increases the hydrogen burning rate, thereby causing the He core to reach the critical mass faster and advancing the He flash. An increase in NMM results in a higher peak luminosity for the first He flash, a more off-center ignition position, and sub-flashes with higher luminosities, shorter intervals, and higher frequency. We found that the internal gravity wave (IGW) mixing generated by the He flash can induce sufficient mixing in the radiative zone, turning the overshoot region into a low-Dmix bottleneck within the stellar interior. The increase in NMM in the model narrows the overshoot bottleneck region, enabling Li to enter the surface convection zone more quickly, thereby enhancing the enrichment effect of IGW mixing on surface Li. For models incorporating both NMM and IGW mixing, the reduction in the overshoot bottleneck region allows them to effectively produce super Li-rich red clump star samples.

astro-ph.SR↗

arXiv2025

The neutrino luminosity and energy spectrum of nova outburst

The nova outburst can produce a large number of neutrinos, whether it is the nuclear reaction process during the explosion or the shock wave acceleration proton process. We study the low-energy nuclear and thermal neutrino luminosity of novae with CO white dwarf (WD) mass ranging from 0.6 to 1.1 $\rm M_{\odot}$ with different accretion rates $\dot{M}$, core temperatures $(T_{\mathrm{C}})$, and mixing degrees. We find that during the accretion phase, low-energy neutrinos are mainly produced by pp chains and plasma decay, and photon luminosity is greater than low-energy nuclear and thermal neutrino luminosity. During the thermonuclear runaway (TNR) phase, low-energy neutrinos are mainly produced by the CNO cycle and photon-neutrino, and the low-energy nuclear and thermal neutrino luminosity far exceeds the photon luminosity. We find that the more massive the WD, the shorter the cycle time and the higher the low-energy nuclear neutrino luminosity. The higher the accretion rate, the lower the low-energy nuclear neutrino luminosity. If the accretion mixing effect is not taken into account, the outburst interval becomes longer, the low-energy nuclear neutrino luminosity will be increased. And for the cooler nova model $(T_{\mathrm{C}}=1\times10^{7}\rm K)$, the low-energy nuclear neutrino luminosity will be lower during the accretion phase and higher at the TNR. We also predict the neutrino luminosity and energy spectrum of the upcoming recurrent nova T Coronae Borealis (T CrB). We estimate that the next T CrB outburst has a low-energy nuclear neutrino peak luminosity of $2.7\times10^{8}\ \rm L_{ν,\odot}$ and a low-energy nuclear neutrino outburst duration of 88 days. In addition, we predict that the high-energy hadronic neutrino flux produced by T CrB nova can not be observed by the current-generation IceCube.

astro-ph.SR↗

arXiv2024

Identifying Hierarchically Triple Star Systems with Gaia DR3 and LAMOST

Triple star systems are critical for understanding stellar dynamics and compact objects in astrophysics, yet confirmed hierarchical triples identified via spectroscopy remain limited. In this study, we identified 23 triple systems by cross-matching the Gaia DR3 non-single star catalog with LAMOST DR10 spectroscopic data; 18 of them are new discoveries. For two well-observed triples, we performed radial velocity curve fitting and light curve analysis to determine their orbital parameters, with inner and outer periods of 1.26 days and 656 days for one triple, and 3.42 days and 422 days for the other. We compared the results with other studies. We also analyzed the radial velocities (RVs) of these 23 triples, revealing a range of $V$ from approximately 40~km~s$^{-1}$ to 210~km~s$^{-1}$. Due to spectral resolution and detection limitations, velocity differences below 45~km~s$^{-1}$ in binaries and below 90~km~s$^{-1}$ in the inner binaries of triple systems are challenging to detect. Consequently, our detection range for inner orbital periods is restricted to 0.2--20 days, with the highest efficiency for periods under 10 days. These findings underscore the advantage of spectroscopic observations for identifying triple systems with short inner orbital periods.

astro-ph.SR↗

arXiv2024

When LAMOST meets Gaia DR3 Exploring the metallicity of open clusters

Context. Open clusters (OCs) are valuable probes of stellar population characteristics. Their age and metallicity provide insights into the chemical enrichment history of the Milky Way. By studying the metallicity of OCs, we can explore the spatial distribution of composition across the Galaxy and understand stellar birth radii through chemical tagging. However, inferring the original positions of OCs remains a challenge. Aims. This study investigates the distribution of metallicity in the solar neighborhood using data from Gaia DR3 and LAMOST spectra. By measuring accurate ages and metallicities, we aim to derive birth radii and understand stellar migration patterns. Methods. We selected 1131 OCs within 3 kpc of the Sun from Gaia DR3 and LAMOST DR8 low-resolution spectra (R=1800). To correct the LAMOST data, we incorporated high-resolution spectra from GALAH DR3 (R=28000) using an artificial neural network. The average metallicity of the OCs was derived from reliable [Fe/H] values of their members. We examined the metallicity distribution across the Galaxy and calculated birth radii based on age and metallicity. Results. The correction method reduces the systematic offset in LAMOST data. We found a metallicity gradient as a function of Galactocentric distance and guiding radii. Comparisons with chemo-dynamic simulations show that observed metallicity values are slightly lower than predicted when uncertainties are ignored, but the metallicity gradients align with previous studies. We also inferred that many OCs near the Sun likely originated from the outer Galactic disk.

astro-ph.GA↗

arXiv2024

A possible formation scenario of the Gaia BH1: inner binary merger in triple systems

Based on astrometric measurements and spectral analysis from $Gaia$ DR3, two quiescent black hole (BH) binaries, $Gaia$ BH1 and BH2, have been identified. Their origins remain controversial, particularly for $Gaia$ BH1. By considering a rapidly rotating ($ω/ω_{\rm crit} = 0.8$) and strongly magnetized ($B_{\rm 0} = 5000$ G) merger product, we find that, at typical Galactic metallicity, the merger product can undergo efficient chemically homogeneous evolution (CHE). This results in the merger product having a significantly smaller radius during its evolution compared to that of a normally evolving massive star. Under the condition that the initial triple stability is satisfied, we use the Multiple Stellar Evolution (MSE) code and the MESA code to identify an initial hierarchical triple that can evolve into $Gaia$ BH1. It initially consists of three stars with masses of 9.03 $M_{\odot}$, 3.12 $M_{\odot}$, and 1 $M_{\odot}$, with inner and outer orbital periods of 2.21 days and 121.92 days, and inner and outer eccentricities of 0.41 and 0.45, respectively. This triple initially experiences triple evolution dynamics instability (TEDI) followed by Roche lobe overflow (RLOF). During RLOF, the inner orbit shrinks, and tidal effects gradually suppress the TEDI. Eventually, the inner binary undergoes a merger through contact (or collision). Finally, using models of rapidly rotating and strongly magnetic stars, along with standard core-collapse supernova (SN) or failed supernova (FSN) models, we find that a PMB consisting of an 12.11 $M_{\odot}$ merger product and a 1 $M_{\odot}$ companion star (originally an outer tertiary) can avoid RLOF. After a SN or FSN with a low ejected mass of $\sim$0.22 $M_{\odot}$ and a low kick velocity ($46^{+25}_{-33}$ ${\rm km/s}$ or $9^{+16}_{-8}$ ${\rm km/s}$), the PMB can form $Gaia$ BH1 in the Galactic disk.

astro-ph.SR↗