arXiv subjects

Wen-Xu Lin

Publications and source records attributed to Wen-Xu Lin.

6 recordsLinked to original sources

arXiv2026

Two Potential Exoplanets around A-type Stars Selected from 18 Planetary Candidates

We screen and analyze exoplanet candidates around A-type stars (defined as Teff between 7500 and 10,000 K) observed by the Transiting Exoplanet Survey Satellite to evaluate their likelihood of being genuine exoplanets. Our analysis involves transit signal searches, light-curve detrending, estimation of nearby-source contamination, and calculation of false-positive probabilities (FPPs). Among the 18 candidates analyzed, four exhibit relatively low FPP values (<15%). Two candidates are excluded from further analysis due to the lack of stellar parameter data. Six candidates show no clearly detectable transit signals, likely due to shallow or weak features, while six candidates exhibit relatively high FPP values, leaving their authenticity uncertain. Among the four low-FPP targets, two-TIC 48031665 and TIC 259230140-stand out as the most promising. TIC 48031665 shows a very shallow transit signal but has a very low FPP and minimal nearby starlight contamination. TIC 259230140 displays a clear U-shaped transit light curve typical of planetary transits, along with slightly higher yet still low FPP and contamination levels. These two objects are therefore considered the most promising candidates identified in this study.

astro-ph.EP↗

arXiv2025

Comprehensive Parameter Determination of Exoplanet through Asteroseismic Host Star Constraints

This study develops a robust framework for exoplanet characterization by leveraging asteroseismic constraints on host stars. Using precise photometric data from missions such as \textit{Kepler} and \textit{TESS}, we derive stellar parameters, including mass, radius, and age, with high accuracy through asteroseismic analysis. These stellar parameters are incorporated as priors in a Bayesian framework to refine planetary properties such as mass, radius, and orbital parameters. By applying Markov Chain Monte Carlo (MCMC) methods, we extract posterior distributions of planetary parameters, achieving significant improvements in precision and reliability. This approach is particularly effective for systems with evolved host stars, where precise stellar properties are essential for resolving uncertainties in planetary characterization. The results demonstrate the importance of asteroseismology in bridging stellar astrophysics and exoplanet science, enabling detailed studies of planetary system architectures and their dependence on host star properties. Our methodology underscores the synergy between stellar and planetary studies, paving the way for future research on exoplanet populations. This work provides a foundation for utilizing data from upcoming missions like \textit{PLATO}, ensuring continued advancements in the precision and scope of exoplanet characterization.

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arXiv2024

Decoding the Future of Exoplanets: Asteroseismic Confirmation of Subgiant and Red Giant Hosts

Asteroseismology has emerged as a powerful tool to unravel the intricate relationships between evolved stars and their planetary systems. In this study, we leverage this technique to investigate the evolutionary stages of five exoplanet host stars, each exhibiting solar-like oscillations. Building on our previous work that identified two host stars as red clump and red giant branch (RGB) stars, this study focuses on a new and broader sample. By precisely measuring asteroseismic parameters such as the period spacing of dipole gravity modes ($\Delta\Pi_{1}$), we provide definitive confirmation of these stars' evolutionary states as subgiants or RGB stars. These results are not only crucial for understanding the internal structures of evolved stars but also for predicting the eventual fate of their planetary companions, which may face engulfment as their host stars expand. This research highlights the profound role of asteroseismology in advancing our knowledge of planetary system evolution and opens new pathways for exploring how stellar evolution impacts planetary survival. Our findings set the stage for future studies on the dynamic fates of exoplanets, providing key insights into the intricate processes of stellar and planetary evolution.

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arXiv2024

Evolutionary states and triplicity of four massive semi-detached binaries with long-term decreasing orbital periods in the LMC

The massive semi-detached binary with a long-term decreasing orbital period may involve a rapid mass-transfer phase in Case A, and thus they are good astrophysical laboratories for investigating the evolution of massive binary stars. In this work, by using the long-term observational light curves from the OGLE project and other data in the low-metallicity LMC, four semi-detached massive binaries with long-term decreases in the orbital periods are detected from 165 EB-type close binaries. It is found that the more massive component in S07798 is filling its Roche lobe where the period decrease is caused by mass transfer from the primary to the secondary. However, the other three (S03065, S12631, S16873) are semi-detached binaries with a lobe-filling secondary where the mass transfer between the components should cause the period to increase if the angular momentum is conservative. The long-term period decreases in these three systems may be caused by the angular momentum loss. Additionally, the orbital periods of three systems (S03065, S07798, S16873) are detected to show cyclic variation with periods shorter than 11 years, which can be plausibly explained by the presence of close-in third bodies in these massive binaries. Based on all of these results, it is suggested that the detected four semi-detached binaries almost have multiplicity. The companion stars are crucial for the origin and evolution of these massive close binaries.

astro-ph.SR↗

arXiv2024

Revealing the Fate of Exoplanet Systems: Asteroseismic Identification of Host Star in the Red Clump or Red Giant Branch

Determining the evolutionary stage of stars is crucial for understanding the evolution of exoplanetary systems. In this context, Red Giant Branch (RGB) and Red Clump (RC) stars, stages in the later evolution of stars situated before and after the helium flash, harbor critical clues to unveiling the evolution of planets. The first step in revealing these clues is to confirm the evolutionary stage of the host stars through asteroseismology. However, up to now, host stars confirmed to be RGB or RC stars are extremely rare. In this investigation, we present a comprehensive asteroseismic analysis of two evolved stars, HD 120084 and HD 29399, known to harbor exoplanets, using data from the Transiting Exoplanet Survey Satellite (TESS). We have discovered for the first time that HD 120084 is a Red Clump star in the helium-core burning phase, and confirmed that HD 29399 is a Red Giant Branch star in the hydrogen-shell burning phase. Through the precise measurement of asteroseismic parameters such as $\nu_{max}$, $\Delta\nu$ and $\Delta\Pi_{1}$ we have determined the evolutionary states of these stars and derived their fundamental stellar parameters. The significance of this study lies in the application of automated techniques to measure asymptotic period spacings in red giants, which provides critical insights into the evolutionary outcomes of exoplanet systems. We demonstrate that asteroseismology is a potent tool for probing the internal structures of stars, thereby offering a window into the past and future dynamics of planetary orbits. The presence of a long-period giant planet orbiting HD 120084, in particular, raises intriguing questions about the potential engulfment of inner planets during the host star's expansion, a hypothesis that warrants further investigation.

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arXiv2024

Using Asteroseismology to Calibrate the Physical Parameters of Confirmed Exoplanets and Their Evolved Host Stars

Asteroseismology offers a profound window into stellar interiors and has emerged as a pivotal technique in exoplanetary research. This study harnesses the Transiting Exoplanet Survey Satellite (TESS) observations to reveal, for the first time, the asteroseismic oscillations of four exoplanet-hosting stars. Through meticulous analysis, we extracted their asteroseismic signatures, enabling the precise determination of stellar masses, radii, luminosities, and surface gravities. These parameters exhibit markedly reduced uncertainties compared to those derived from spectroscopic methods. Crucially, the exoplanets orbiting these stars were initially identified via radial velocity measurements. The refinement of host stellar masses necessitates a corresponding adjustment in planetary characteristics. Employing asteroseismology, we recalibrated the exoplanets' minimum masses and semi-major axes - a novel approach in the field. For instance, the exoplanet HD 5608 b's minimum mass, denoted as Msini, was ascertained to be 1.421 +/- 0.091 M_J through the integration of asteroseismic and radial velocity data. Similarly, two planets within the 7 CMa system yielded Msini values of 1.940 +/- 0.064 MJ and 0.912 +/- 0.067 M_J, respectively. Two planets in HD 33844 system presented Msini figures of 1.726 +/- 0.145 M_J and 1.541 +/- 0.182 M_J, while the HIP 67851 system's planets registered Msini at 1.243 +/- 0.139 M_J and a notably higher 5.387 +/- 0.699 M_J. This investigation extends beyond mere parameter refinement; it underscores the synergy between asteroseismology and exoplanetology, yielding unprecedented precision in system metrics. Focusing on quartet of K-type giants in advanced evolutionary phases, our work positions these systems as invaluable astrophysical laboratories, offering insights into the potential trajectory of our own solar system's fate.

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