New Astronomy最新文献

{"title":"An extensive search for stable periodic orbits of the equal-mass zero angular momentum three-body problem","authors":"Ivan Hristov ,&nbsp;Radoslava Hristova ,&nbsp;Kiyotaka Tanikawa","doi":"10.1016/j.newast.2026.102528","DOIUrl":"10.1016/j.newast.2026.102528","url":null,"abstract":"<div><div>A special 2D initial conditions’ domain of the equal-mass zero angular momentum planar three-body problem, which has been formerly studied, is analyzed to deepen the knowledge of the stability regions in it. The decay times in the domain are carefully computed. Four stability regions are established. 971 verified initial conditions for linearly stable periodic collisionless orbits are found. Many of these identified initial conditions are new ones. The periodic orbits of each stability region are characterized by a certain pattern in their syzygy sequences. Additional computations show that the orbits found should be considered as candidates for KAM-stable orbits.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"125 ","pages":"Article 102528"},"PeriodicalIF":2.1,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A charged anisotropic conformal star model in core–envelope setting","authors":"Yasin K. Kowa ,&nbsp;Jonas W. Jape ,&nbsp;Jefta M. Sunzu ,&nbsp;Sunil D. Maharaj","doi":"10.1016/j.newast.2026.102529","DOIUrl":"10.1016/j.newast.2026.102529","url":null,"abstract":"<div><div>We develop a new exact model to explore the behavior and properties of a charged anisotropic core–envelope star in general relativity. The model incorporates a quadratic equation of state in the core and a modified Van der Waals equation of state in the envelope, under the influence of a conformal Killing vector. Our analysis reveals that the matter variables within the star exhibit well behaved characteristics. The model satisfies several stability conditions, the energy and equilibrium conditions, and it is free from physical and geometric singularities. Additionally, the mass, compactness, and surface redshift are within observed ranges. We have also regained radii and masses consistent to CenX-3, SMCX-1, and HerX-1 known stars.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"125 ","pages":"Article 102529"},"PeriodicalIF":2.1,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Out-of-plane equilibrium points in the rotating mass dipole model with non-spherical radiating bodies","authors":"Aguda Ekele Vincent","doi":"10.1016/j.newast.2026.102531","DOIUrl":"10.1016/j.newast.2026.102531","url":null,"abstract":"<div><div>In the present work, the dynamics of a rotating mass dipole system consisting of two masses connected by a massless rigid rod within the framework of the circular restricted three-body problem (CRTBP) is analyzed. We consider that the two primaries have equal masses, equal non-sphericity (oblate/prolate shapes) and equal values of radiation pressure forces that have either extremely strong radiation emission which surpasses the gravitational force or very weak which simply reduces the effect of gravitation. The number, locations, and stability of out-of-plane equilibrium points, as well as structure of zero-velocity curves (ZVCs) under the influence of the perturbations of radiation pressure, force ratio and non-sphericity of the primaries are examined, using numerical methods. It is found that, these out-of-plane equilibrium points emerge in symmetrical pairs and, depending on the sign and magnitude of the perturbing parameters, their number may be either zero, two <span><math><mrow><mo>(</mo><msubsup><mrow><mi>E</mi></mrow><mrow><mn>1</mn><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow></mrow><mrow><mi>z</mi></mrow></msubsup><mo>)</mo></mrow></math></span> along the <span><math><mrow><mi>O</mi><mi>z</mi></mrow></math></span> axis, four <span><math><mrow><mo>(</mo><msubsup><mrow><mi>E</mi></mrow><mrow><mn>3</mn><mrow><mo>(</mo><mn>4</mn><mo>)</mo></mrow></mrow><mrow><mi>x</mi><mi>z</mi></mrow></msubsup><mspace></mspace><mtext>and</mtext><mspace></mspace><msubsup><mrow><mi>E</mi></mrow><mrow><mn>5</mn><mrow><mo>(</mo><mn>6</mn><mo>)</mo></mrow></mrow><mrow><mi>x</mi><mi>z</mi></mrow></msubsup><mo>)</mo></mrow></math></span> on the <span><math><mrow><mi>O</mi><mi>x</mi><mi>z</mi></mrow></math></span> plane (outside the axes) or six <span><math><mrow><mo>(</mo><msubsup><mrow><mi>E</mi></mrow><mrow><mn>1</mn><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow></mrow><mrow><mi>z</mi></mrow></msubsup><mo>,</mo><msubsup><mrow><mi>E</mi></mrow><mrow><mn>3</mn><mrow><mo>(</mo><mn>4</mn><mo>)</mo></mrow></mrow><mrow><mi>x</mi><mi>z</mi></mrow></msubsup><mspace></mspace><mtext>and</mtext><mspace></mspace><msubsup><mrow><mi>E</mi></mrow><mrow><mn>5</mn><mrow><mo>(</mo><mn>6</mn><mo>)</mo></mrow></mrow><mrow><mi>x</mi><mi>z</mi></mrow></msubsup><mo>)</mo></mrow></math></span> on the <span><math><mrow><mi>O</mi><mi>x</mi><mi>z</mi></mrow></math></span> plane. We observe that the out-of-plane equilibria in symmetric positions with respect to both axes <span><math><mrow><mi>O</mi><mi>x</mi></mrow></math></span> and <span><math><mrow><mi>O</mi><mi>z</mi></mrow></math></span> are the most sensitive in position to the variations of perturbing forces. Our results also reveal that the perturbing parameters have impact on the structure of the zero-velocity curves. Furthermore, the stability of these points is examined in the linear sense and it is found that all equilibrium points are unstable in general.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"125 ","pages":"Article 102531"},"PeriodicalIF":2.1,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TESS light curve and apsidal motion in the eccentric eclipsing binary V871 Aquilae","authors":"Marek Wolf ,&nbsp;Hana Kučáková ,&nbsp;Waldemar Ogłoza ,&nbsp;Martin Mašek ,&nbsp;Andrej Mudray","doi":"10.1016/j.newast.2026.102520","DOIUrl":"10.1016/j.newast.2026.102520","url":null,"abstract":"<div><div>We present an apsidal motion and light curve analysis of the eccentric eclipsing binary V871 Aql, which contains two early-type stars in an eccentric orbit with a short orbital period of 2.95 d. We used the light curve from the Transiting Exoplanet Survey Satellite (<span>Tess</span>), which observed V871 Aql in one sector, to determine its photometric properties and precise orbital ephemeris. The solution of the <span>Tess</span> light curve in <span>Phoebe</span> results in a detached configuration of two nearly identical components. The temperature of the primary component was fixed to <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><mn>14</mn><mspace></mspace><mn>000</mn><mo>±</mo><mn>1000</mn></mrow></math></span> K according to <span>Vosa 7.5</span>, which gives us <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>=</mo><mn>13</mn><mspace></mspace><mn>800</mn><mo>±</mo><mn>1000</mn></mrow></math></span> K for the secondary. The spectral type of the primary component was estimated to be B7, and the photometric mass ratio was derived <span><math><mrow><mi>q</mi><mo>≃</mo><mn>0</mn><mo>.</mo><mn>99</mn></mrow></math></span>. The preliminary physical parameters of both similar components are <span><math><mrow><msub><mrow><mi>M</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><mn>3</mn><mo>.</mo><mn>91</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>40</mn></mrow></math></span> M<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span> and <span><math><mrow><msub><mrow><mi>M</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>=</mo><mn>3</mn><mo>.</mo><mn>87</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>40</mn></mrow></math></span> M<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span> and <span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>=</mo><mn>3</mn><mo>.</mo><mn>076</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>03</mn></mrow></math></span> R<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span> and <span><math><mrow><msub><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>=</mo><mn>3</mn><mo>.</mo><mn>067</mn><mo>±</mo><mn>0</mn><mo>.</mo><mn>03</mn></mrow></math></span> R<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>. The current <span><math><mrow><mi>O</mi><mspace></mspace><mo>−</mo><mspace></mspace><mi>C</mi></mrow></math></span> diagram that spans almost the past 80 years indicates the clear presence of an apsidal motion with a period of about 250 years. No signs of a third body were found in the <span><math><mrow><mi>O</mi><mspace></mspace><mo>−</mo><mspace></mspace><mi>C</mi></mrow></math></span> diagram or in the light-curve solution.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"125 ","pages":"Article 102520"},"PeriodicalIF":2.1,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asteroseismic and spectral fitting study of the double DA white dwarf TIC 0030545382","authors":"Y.H. Chen ,&nbsp;Z. Sun ,&nbsp;C.M. Duan ,&nbsp;Z. Han ,&nbsp;B.K. Sun ,&nbsp;H. Shu","doi":"10.1016/j.newast.2025.102516","DOIUrl":"10.1016/j.newast.2025.102516","url":null,"abstract":"<div><div>Using TESS observations in 2019, 2021, and 2023 for TIC 0030545382, we extracted frequencies with the Period04 software and reproduced the four intrinsic frequencies identified by Romero et al. The light curve is a typical pulsating white dwarf light curve, without obvious binary occultation information. We evolved about 7.56 million DAV star models using <span>WDEC</span> code and obtained theoretical pulsation periods, which were used to fit the four observed modes. The four observed modes provide weak constraints on the fitting models and five optimal models are derived. Using <span>WDTOOLS</span> module, we performed RV spectral fitting, single white dwarf spectral fitting, and double white dwarfs spectral fitting on three spectra of TIC 0030545382 from SOAR telescope and Gemini South telescope. The fitting of Balmer absorption lines for the three spectra indicates the complexity, diversity, and inconsistency of their RVs, which support the idea that TIC 0030545382 is a binary system. Comprehensive analysis and spectral fitting of double white dwarfs suggest that TIC 0030545382 is a double DA type white dwarfs system, with one non pulsating of <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>eff</mi></mrow></msub></math></span> around 15600-17500<!--> <!-->K and the other pulsating. Combining the asteroseismological results with the trigonometric parallax distance, this DAV WD should have a stellar mass exceeding 0.8<!--> <span><math><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>. The inclination angle of the binary orbit to the line of sight direction is likely close but not equal to 90 degrees. The future of this double white dwarf system promises to be highly intriguing, necessitating further spectroscopic observations to obtain more precise physical parameters.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"124 ","pages":"Article 102516"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical abundance analysis of two bright peculiar giant stars: HD 187818 and HD 205605","authors":"B.S. Pessoa ,&nbsp;A. Sonally ,&nbsp;A.C.S. Santos ,&nbsp;N. Holanda","doi":"10.1016/j.newast.2025.102514","DOIUrl":"10.1016/j.newast.2025.102514","url":null,"abstract":"<div><div>Giant stars are excellent laboratories for testing standard stellar evolution and nucleosynthesis, as well as for exploring non-standard mixing processes. In this work, we present a description of two K giant stars with an overabundance of lithium. For this purpose, we adopted <span>atlas9</span> atmosphere models and used the spectral synthesis code MOOG, both assuming LTE conditions. We determined the atmospheric parameters (<span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>eff</mi></mrow></msub></math></span>, <span><math><mrow><mo>log</mo><mspace></mspace><mi>g</mi></mrow></math></span>, [Fe/H], and <span><math><msub><mrow><mi>ξ</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span>), abundance for light species (Li, C, N, and O), carbon isotopic ratio (¹²C/¹³C), stellar parameters, and discuss these results in the context of the chemical puzzle of the so-called Li-rich giants. The targets are bright stars in the southern hemisphere, neglected so far, and present a peculiar absorption line at <span><math><mi>λ</mi></math></span> 6708<!--> <!-->Å <!--> <!-->(<span><math><mrow><mo>log</mo><mspace></mspace><mi>ɛ</mi></mrow></math></span>(Li)<span><math><msub><mrow></mrow><mrow><mi>NLTE</mi></mrow></msub></math></span> <!--> <span><math><mo>&gt;</mo></math></span> <!--> <!-->1.50<!--> <!-->dex). The position of these stars in the Kiel diagram indicates that they are intermediate-mass objects and fall within the region most frequently occupied by Li-rich giants, RGB and core-helium burning phase.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"124 ","pages":"Article 102514"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multiband photometric study of RR Lyrae stars in M53 (NGC 5024)","authors":"Shantanu A. Gaur ,&nbsp;Nitesh Kumar ,&nbsp;Anupam Bhardwaj ,&nbsp;Aasheesh Raturi","doi":"10.1016/j.newast.2025.102515","DOIUrl":"10.1016/j.newast.2025.102515","url":null,"abstract":"<div><div>We present a multiband (UBVRI) time-series photometric study of RR Lyrae (RRL) stars in the globular cluster Messier 53 (NGC 5024) to refine their pulsation properties and determine a precise cluster distance. The archival photometric data includes images taken over 22 years and 3 months using different optical telescopes, providing an excellent time baseline to investigate light curves of variable stars. Using Lomb–Scargle periodogram, we derived accurate periods for 29 fundamental-mode (RRab) and 35 first-overtone (RRc) RRLs. Template-fitting to phase-folded light curves provided robust mean magnitudes and amplitudes. The refined periods confirm M53 as an Oosterhoff II cluster, with a mean period of 0.649 days for RRab and 0.346 days for RRc, and a high RRc fraction (54.7%). Most RRLs align with the horizontal branch in the color-magnitude diagram, while a few outliers result from blending effects. Period-amplitude diagrams show RRab stars following the Oosterhoff II locus. We derived I-band period-luminosity and multi-band period-Wesenheit relations, comparing them with theoretical predictions. A weighted mean distance modulus of 16.242 ± 0.05 mag yields a cluster distance of 17.717 ± 0.408 kpc, in agreement with recent estimates based on parallaxes from Gaia data.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"124 ","pages":"Article 102515"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Collision frequency between dark matter subhaloes within Milky Way-like galaxies","authors":"Koki Otaki ,&nbsp;Yudai Kazuno ,&nbsp;Masao Mori","doi":"10.1016/j.newast.2025.102501","DOIUrl":"10.1016/j.newast.2025.102501","url":null,"abstract":"<div><div>In the standard cold dark matter (CDM) model, sub-galactic structures hierarchically collide and merge to build up larger structures. Mergers and collisions between dwarf galaxies and dark matter subhaloes (DMSHs) play an important role in the evolution and formation of structures within a massive galaxy. We investigate the collision frequency between DMSHs associated with a massive host galaxy such as the Milky Way. We analytically estimate the density distribution of DMSH pairs for the relative distance and relative velocity (<span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>rel</mi></mrow></msub></math></span>-<span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>rel</mi></mrow></msub></math></span>) and the distance from the centre of the host halo and relative velocity (<span><math><mi>r</mi></math></span>-<span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>rel</mi></mrow></msub></math></span>) planes, based on the distribution function of the host halo in the phase space. Then, we evaluate the collision frequencies of DMSHs by integrating the orbital evolution of DMSHs in Milky-Way-like host haloes selected from cosmological <span><math><mi>N</mi></math></span>-body simulations. The frequency of violent encounters, in which the relative distance of DMSHs is shorter than the sum of scale radii, is averaged as <span><math><mrow><mn>2</mn><mo>.</mo><mn>1</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>2</mn></mrow></msup><mspace></mspace><msup><mrow><mi>Gyr</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>. Since the time scale of violent encounters, <span><math><mrow><mn>4</mn><mo>.</mo><mn>7</mn><mspace></mspace><mi>Myr</mi></mrow></math></span>, is shorter than the dynamical time of the host halo, collisions between DMSHs occur frequently within the host halo. Although interactions between DMSHs produce pairs with higher relative velocities, the density distributions of all and colliding pairs between DMSHs provided by numerical results are approximately similar to those of the analytical model neglecting the interactions of DMSHs on <span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>rel</mi></mrow></msub></math></span>-<span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>rel</mi></mrow></msub></math></span> plane for all pairs and <span><math><mi>r</mi></math></span>-<span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>rel</mi></mrow></msub></math></span> plane for colliding pairs. We compare our results with observed colliding dwarf galaxies and provide insight into the abundance of DMSHs.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"124 ","pages":"Article 102501"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145618632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rapid inversion method for parameters of contact binaries based on intelligent optimization algorithms","authors":"Xiangyun Zeng ,&nbsp;Yubo Li ,&nbsp;Huiling He ,&nbsp;Sheng Zheng ,&nbsp;Gaogui Xu ,&nbsp;Zhengxue Chang ,&nbsp;Rongjun Zhang ,&nbsp;Ali Esamdin","doi":"10.1016/j.newast.2025.102511","DOIUrl":"10.1016/j.newast.2025.102511","url":null,"abstract":"<div><div>Extensive research on contact binaries has led to the publication of a significant number of light curves. A key challenge now is efficiently deriving the fundamental physical parameters of contact binaries from these light curves. This paper presents a method that combines a deep learning-based light curve generative model with Differential Evolution (DE) to rapidly derive these parameters. The method utilizes a neural network to directly link the physical parameters of contact binaries to their light curves. The DE and Markov Chain Monte Carlo (MCMC) methods are used separately to explore optimal parameter combinations. Experimental results show that the DE method is approximately 90% faster than the MCMC method in parameter inversion, while maintaining higher precision.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"124 ","pages":"Article 102511"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic activity and rotational modulation of the secondary star in the V471 Tau eclipsing binary system observed by K2 and TESS","authors":"Ezgi Yoldaş","doi":"10.1016/j.newast.2025.102513","DOIUrl":"10.1016/j.newast.2025.102513","url":null,"abstract":"<div><div>V471 Tau is a rare post common envelope binary consisting of a white dwarf and a K2V star, on the verge of entering a cataclysmic phase. This study presents the results of photometric analyses of V471 Tau using data obtained from the Kepler (K2 mission) and TESS space telescopes. The system, observed with high precision and sensitivity by both satellites, exhibits sinusoidal rotational modulation due to cool starspots outside eclipses, as well as short term flares. These phenomena were detected, analyzed, and modeled separately. For the flares, we applied a One Phase Exponential Association (OPEA) model and derived the corresponding parameters. Unlike previous studies, we constructed the cumulative flare frequency distribution using “flare equivalent durations”. The spot activity of the K2V component was analyzed using photometric data from both satellites, revealing three distinct spots consistently detected in each dataset. The long term photometric behavior of the stellar spots was further examined using data spanning a decade. The results show that one spot undergoes significant longitudinal migration, whereas the other two remain nearly constant in position. In addition, ellipsoidal effects and variations in the depth of the primary minimum were investigated to evaluate their contribution to the overall light curve morphology.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"124 ","pages":"Article 102513"},"PeriodicalIF":2.1,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145685402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}