Pub Date : 2025-12-10DOI: 10.1016/j.newast.2025.102511
Xiangyun Zeng , Yubo Li , Huiling He , Sheng Zheng , Gaogui Xu , Zhengxue Chang , Rongjun Zhang , Ali Esamdin
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.
{"title":"Rapid inversion method for parameters of contact binaries based on intelligent optimization algorithms","authors":"Xiangyun Zeng , Yubo Li , Huiling He , Sheng Zheng , Gaogui Xu , Zhengxue Chang , Rongjun Zhang , 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":"2025-12-10","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}
Pub Date : 2025-12-05DOI: 10.1016/j.newast.2025.102513
Ezgi Yoldaş
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.
{"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":"2025-12-05","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}
Pub Date : 2025-11-21DOI: 10.1016/j.newast.2025.102501
Koki Otaki , Yudai Kazuno , Masao Mori
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 (-) and the distance from the centre of the host halo and relative velocity (-) 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 -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 . Since the time scale of violent encounters, , 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 - plane for all pairs and - plane for colliding pairs. We compare our results with observed colliding dwarf galaxies and provide insight into the abundance of DMSHs.
{"title":"Collision frequency between dark matter subhaloes within Milky Way-like galaxies","authors":"Koki Otaki , Yudai Kazuno , 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":"2025-11-21","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}
Pub Date : 2025-11-18DOI: 10.1016/j.newast.2025.102498
Chukwuebuka J. Ugwu , James O. Chibueze , Willice O. Obonyo , Mavis Seidu
This work explored the spatial distribution of C17O, SiO, HC3N and SO2 molecules, as well as the energetics of outflows in G358.460.39 proto-cluster using ALMA band 7 archival data, with the aim of providing an improved understanding of its protostellar nature, gas kinematics and dynamics. G358.460.39 is previously known to consist of 4 dust continuum cores (MM1a, MM1b, MM1c and MM2). The integrated intensity map of C17O reveals filamentary and dumbbell-shaped structures that are probably compressed gases from the expansion of the HII region MM2. The SiO emission reveals spatially overlapped blue and red outflow lobes, likely driven by an unresolved young stellar object (YSO) in MM1a. The spatial distribution of HC3N and SO2 molecules in MM1a shows a compact morphology, with no detectable HC3N and SO2 emissions in the other cores. The SO2 emission reveals a clear velocity gradient in MM1a, as well as large velocity dispersion ( 3 km s) within the inner core of MM1a, which are consistent with rotating structures. We estimated the mass, momentum and energy outflow rate, as well as other outflow parameters. The SiO outflow exhibits a different morphology compared to the 12CO outflow morphology previously observed in MM1a. The SiO and 12CO outflows are probably associated with disks of separate cores with one face-on and the other edge-on, pointing to multiplicity of YSOs in MM1a. The properties of MM1a indicate that it is a massive protostar that is actively accreting and undergoing star formation.
本研究利用ALMA波段7档案数据，探索了G358.46−0.39原星团中C17O、SiO、HC3N和SO2分子的空间分布，以及流出物的能量学，旨在更好地了解其原恒星性质、气体运动学和动力学。G358.46−0.39先前已知由4个尘埃连续体核心（MM1a, MM1b， MM1c和MM2）组成。C17O的综合强度图显示了丝状和哑铃状结构，可能是HII区域MM2膨胀产生的压缩气体。SiO发射显示空间上重叠的蓝色和红色流出叶，可能是由MM1a中未解析的年轻恒星物体（YSO）驱动的。MM1a中HC3N和SO2分子的空间分布表现为致密的形态，其他核芯中没有检测到HC3N和SO2的排放。SO2发射在MM1a中显示出明显的速度梯度，以及在MM1a内核内的大速度色散（~ 3 km s−1），这与旋转结构一致。我们估计了质量、动量和能量流出率以及其他流出参数。与先前在MM1a中观察到的12CO流出形态相比，SiO流出表现出不同的形态。SiO和12CO的流出可能与单独核的磁盘有关，一个面朝上，另一个面朝上，这表明MM1a中存在多个yso。MM1a的特性表明它是一颗大质量原恒星，正在活跃地吸积和形成恒星。
{"title":"Insights on gas distribution and dynamics in massive proto-cluster G358.46−0.39: Possible multiplicity in G358.46−0.39 MM1a","authors":"Chukwuebuka J. Ugwu , James O. Chibueze , Willice O. Obonyo , Mavis Seidu","doi":"10.1016/j.newast.2025.102498","DOIUrl":"10.1016/j.newast.2025.102498","url":null,"abstract":"<div><div>This work explored the spatial distribution of C<sup>17</sup>O, SiO, HC<sub>3</sub>N and SO<sub>2</sub> molecules, as well as the energetics of outflows in G358.46<span><math><mo>−</mo></math></span>0.39 proto-cluster using ALMA band 7 archival data, with the aim of providing an improved understanding of its protostellar nature, gas kinematics and dynamics. G358.46<span><math><mo>−</mo></math></span>0.39 is previously known to consist of 4 dust continuum cores (MM1a, MM1b, MM1c and MM2). The integrated intensity map of C<sup>17</sup>O reveals filamentary and dumbbell-shaped structures that are probably compressed gases from the expansion of the HII region MM2. The SiO emission reveals spatially overlapped blue and red outflow lobes, likely driven by an unresolved young stellar object (YSO) in MM1a. The spatial distribution of HC<sub>3</sub>N and SO<sub>2</sub> molecules in MM1a shows a compact morphology, with no detectable HC<sub>3</sub>N and SO<sub>2</sub> emissions in the other cores. The SO<sub>2</sub> emission reveals a clear velocity gradient in MM1a, as well as large velocity dispersion (<span><math><mo>∼</mo></math></span> 3<!--> <!-->km<!--> <!-->s<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>) within the inner core of MM1a, which are consistent with rotating structures. We estimated the mass, momentum and energy outflow rate, as well as other outflow parameters. The SiO outflow exhibits a different morphology compared to the <sup>12</sup>CO outflow morphology previously observed in MM1a. The SiO and <sup>12</sup>CO outflows are probably associated with disks of separate cores with one face-on and the other edge-on, pointing to multiplicity of YSOs in MM1a. The properties of MM1a indicate that it is a massive protostar that is actively accreting and undergoing star formation.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"123 ","pages":"Article 102498"},"PeriodicalIF":2.1,"publicationDate":"2025-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145618207","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}
Pub Date : 2025-11-11DOI: 10.1016/j.newast.2025.102496
Derya Sürgit , Mücahit Kuz , Volkan Bakış , Chris Engelbrecht , Fred Marang
As part of an ongoing programme of observing detached eclipsing binary stars in the southern sky, we present the first analysis of spectroscopic observations of the Algol-type binary system DG Mic. A spectroscopic analysis of mid-resolution spectra allowed us to constrain the effective temperature of the primary component and to test the consistency of the system parameters with its spectral energy distribution (SED). Combined solutions of mid-resolution spectra and TESS, ASAS and WASP light curves imply a system of two almost identical components ( = 0.99) in circular orbits. Our final model shows that the system is a detached binary star. The masses and radii of the primary and secondary components of DG Mic were derived to be 1.65(0.12) M, 1.64(0.18) M and 1.63(0.10) R, 1.91(0.13) R, respectively. According to Geneva evolution models, both components of the system are main-sequence stars and their age is approximately 713 Myr.
{"title":"Absolute parameters of the southern detached eclipsing binary DG Mic","authors":"Derya Sürgit , Mücahit Kuz , Volkan Bakış , Chris Engelbrecht , Fred Marang","doi":"10.1016/j.newast.2025.102496","DOIUrl":"10.1016/j.newast.2025.102496","url":null,"abstract":"<div><div>As part of an ongoing programme of observing detached eclipsing binary stars in the southern sky, we present the first analysis of spectroscopic observations of the Algol-type binary system DG Mic. A spectroscopic analysis of mid-resolution spectra allowed us to constrain the effective temperature of the primary component and to test the consistency of the system parameters with its spectral energy distribution (SED). Combined solutions of mid-resolution spectra and TESS, ASAS and WASP light curves imply a system of two almost identical components (<span><math><mi>q</mi></math></span> = 0.99) in circular orbits. Our final model shows that the system is a detached binary star. The masses and radii of the primary and secondary components of DG Mic were derived to be 1.65(<span><math><mo>±</mo></math></span>0.12) M<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>, 1.64(<span><math><mo>±</mo></math></span>0.18) M<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span> and 1.63(<span><math><mo>±</mo></math></span>0.10) R<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>, 1.91(<span><math><mo>±</mo></math></span>0.13) R<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>, respectively. According to Geneva evolution models, both components of the system are main-sequence stars and their age is approximately 713 Myr.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"123 ","pages":"Article 102496"},"PeriodicalIF":2.1,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520916","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}
Pub Date : 2025-11-11DOI: 10.1016/j.newast.2025.102500
Elena Brylyakova , Marina Afonina , Gayane Tyul’basheva , Sergei B. Popov , Sergei Tyul’bashev
Recently, astrometric and spectroscopic observations resulted in the discovery of several low-mass binaries with invisible components, which are expected to be compact objects. In about two dozen cases, the masses of these components are consistent with neutron stars. We use low-frequency archival data obtained with the Large Phased Array in Pushchino to search for radio emission from five of these systems. For all the systems, we do not detect persistent or periodic emission. In one case (2MASS J1527+3536), we identify a single radio burst with a flux of 13 Jy and a duration of 0.13 s. However, the dispersion measure of the burst does not correspond to an expected value for the source. We discuss several possibilities to explain the properties of this burst.
{"title":"Low-frequency observations of low-mass binary systems with neutron star candidates","authors":"Elena Brylyakova , Marina Afonina , Gayane Tyul’basheva , Sergei B. Popov , Sergei Tyul’bashev","doi":"10.1016/j.newast.2025.102500","DOIUrl":"10.1016/j.newast.2025.102500","url":null,"abstract":"<div><div>Recently, astrometric and spectroscopic observations resulted in the discovery of several low-mass binaries with invisible components, which are expected to be compact objects. In about two dozen cases, the masses of these components are consistent with neutron stars. We use low-frequency archival data obtained with the Large Phased Array in Pushchino to search for radio emission from five of these systems. For all the systems, we do not detect persistent or periodic emission. In one case (2MASS J1527+3536), we identify a single radio burst with a flux of 13 Jy and a duration of 0.13 s. However, the dispersion measure of the burst does not correspond to an expected value for the source. We discuss several possibilities to explain the properties of this burst.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"123 ","pages":"Article 102500"},"PeriodicalIF":2.1,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520957","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}
Pub Date : 2025-11-09DOI: 10.1016/j.newast.2025.102499
Shubhen BISWAS
The recent Gaia data confirm that the Milky Way’s outer stellar disk shows a tangible Keplerian decline in rotation curve. The data also reveal that the stellar velocity maintains a positive correlation with the surface gravity. These revelations present scope for revisiting our understanding of galactic stellar dynamics. Herein, we use the recent interaction model over the post-Newtonian theory of gravity to study celestial dynamics considering the stellar body as an extended object rather than a point particle in space. By jointly considering the central super massive black hole and galactic stellar disk, a rotating stellar body around this combination is theoretically modeled as a two-body system. The model predicts a galactocentric solar rotational speed of for the Milky Way, consistent with the observations.
{"title":"Stellar kinematics of the Milky Way Galaxy in post-Newtonian gravity","authors":"Shubhen BISWAS","doi":"10.1016/j.newast.2025.102499","DOIUrl":"10.1016/j.newast.2025.102499","url":null,"abstract":"<div><div>The recent Gaia data confirm that the Milky Way’s outer stellar disk shows a tangible Keplerian decline in rotation curve. The data also reveal that the stellar velocity maintains a positive correlation with the surface gravity. These revelations present scope for revisiting our understanding of galactic stellar dynamics. Herein, we use the recent interaction model over the post-Newtonian theory of gravity to study celestial dynamics considering the stellar body as an extended object rather than a point particle in space. By jointly considering the central super massive black hole and galactic stellar disk, a rotating stellar body around this combination is theoretically modeled as a two-body system. The model predicts a galactocentric solar rotational speed of <span><math><mrow><mn>226</mn><mspace></mspace><mtext>km</mtext><mo>.</mo><mspace></mspace><msup><mrow><mi>s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> for the Milky Way, consistent with the observations.</div><div>Classification codes: 04.00; 95.10.Ce</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"123 ","pages":"Article 102499"},"PeriodicalIF":2.1,"publicationDate":"2025-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520883","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}
This study presents optical and near-infrared photometric observations, alongside mid-infrared spectroscopic data from the ISO SWS instrument, to examine potential correlations between Aromatic Infrared Band (AIB) features and the optical properties of carbon-rich evolved stars. Identifying such correlations can provide valuable constraints on the evolutionary pathways of low- to intermediate-mass stars beyond the asymptotic giant branch (AGB) phase. Photometric measurements in the U, B, V, R, I, J, H, K, and L bands were obtained for five well-known carbon-rich objects at various post-AGB or planetary nebula (PN) stages: CRL 2688, PN M 2-43, NGC 7027, BD3639, and AFGL 2132. Our analysis reveals that all five objects exhibit prominent AIB features; however, their spectral profiles show notable variation. These differences are attributed to variations in the chemical composition and physical conditions of the surrounding circumstellar material. In particular, the polycyclic aromatic hydrocarbon (PAH) feature is detected in all objects except AFGL 2132, indicating a potentially distinct PAH population or environmental condition in its vicinity. Although these sources share broadly similar evolutionary stages, the observed diversity in AIB characteristics underscores the complexity and heterogeneity of their circumstellar environments.
{"title":"Probing dust and PAH chemistry in evolved carbon-rich nebulae through optical and infrared observations","authors":"Rahul Kumar Anand , Atul Kumar Singh , Saurabh Sharma , Brijesh Kumar , Shantanu Rastogi","doi":"10.1016/j.newast.2025.102494","DOIUrl":"10.1016/j.newast.2025.102494","url":null,"abstract":"<div><div>This study presents optical and near-infrared photometric observations, alongside mid-infrared spectroscopic data from the ISO SWS instrument, to examine potential correlations between Aromatic Infrared Band (AIB) features and the optical properties of carbon-rich evolved stars. Identifying such correlations can provide valuable constraints on the evolutionary pathways of low- to intermediate-mass stars beyond the asymptotic giant branch (AGB) phase. Photometric measurements in the U, B, V, R, I, J, H, K, and L bands were obtained for five well-known carbon-rich objects at various post-AGB or planetary nebula (PN) stages: CRL 2688, PN M 2-43, NGC 7027, BD<span><math><mrow><mo>+</mo><mn>3</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>∘</mo></mrow></msup></mrow></math></span>3639, and AFGL 2132. Our analysis reveals that all five objects exhibit prominent AIB features; however, their spectral profiles show notable variation. These differences are attributed to variations in the chemical composition and physical conditions of the surrounding circumstellar material. In particular, the <span><math><mrow><mn>3</mn><mo>.</mo><mn>28</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> polycyclic aromatic hydrocarbon (PAH) feature is detected in all objects except AFGL 2132, indicating a potentially distinct PAH population or environmental condition in its vicinity. Although these sources share broadly similar evolutionary stages, the observed diversity in AIB characteristics underscores the complexity and heterogeneity of their circumstellar environments.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"123 ","pages":"Article 102494"},"PeriodicalIF":2.1,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520958","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}
Pub Date : 2025-11-07DOI: 10.1016/j.newast.2025.102495
Shinjirou Kouzuma
On the basis of monotonic orbital-period variations, this study aims to identify genuine relationships between binary parameters and the rates of mass transfer (MT), mass loss (ML), and angular momentum loss (AML). Sample binaries with monotonic period variations are collected from the literature, together with well-determined binary parameters. Assuming the monotonic variations are responsible for any one of the MT, ML, and AML, their rates are calculated with the rates of change of period. After selecting crucial parameters using partial least-squares analysis, a parameter that exhibits the closest correlation with any one of the derived rates is further selected using partial regression plots. Moreover, power-law relationships are found for the discovered correlations. The properties of the sample binaries are also investigated by examining associations between binary parameters. In the systems with negative period variations, it is found that the rate of MT from more- to less-massive stars is a function of the primary radius; the AML rate is a function of the fill-out factor. In addition, the relationships between the mass ratio and stellar masses indicate that the ML rate relative to the MT rate decreases with increasing mass ratio below . Meanwhile, in the systems with positive variations, it is found that the rate of MT from less- to more-massive stars is a function of the luminosity ratio and/or mass ratio; the ML rate is a function of the secondary temperature. The discussion also addresses possible processes occurring in the sample binaries.
{"title":"Statistical analysis of eclipsing binaries with monotonic orbital-period variations: A-type W UMa contact systems","authors":"Shinjirou Kouzuma","doi":"10.1016/j.newast.2025.102495","DOIUrl":"10.1016/j.newast.2025.102495","url":null,"abstract":"<div><div>On the basis of monotonic orbital-period variations, this study aims to identify genuine relationships between binary parameters and the rates of mass transfer (MT), mass loss (ML), and angular momentum loss (AML). Sample binaries with monotonic period variations are collected from the literature, together with well-determined binary parameters. Assuming the monotonic variations are responsible for any one of the MT, ML, and AML, their rates are calculated with the rates of change of period. After selecting crucial parameters using partial least-squares analysis, a parameter that exhibits the closest correlation with any one of the derived rates is further selected using partial regression plots. Moreover, power-law relationships are found for the discovered correlations. The properties of the sample binaries are also investigated by examining associations between binary parameters. In the systems with negative period variations, it is found that the rate of MT from more- to less-massive stars is a function of the primary radius; the AML rate is a function of the fill-out factor. In addition, the relationships between the mass ratio and stellar masses indicate that the ML rate relative to the MT rate decreases with increasing mass ratio below <span><math><mrow><mo>∼</mo><mn>0</mn><mo>.</mo><mn>46</mn></mrow></math></span>. Meanwhile, in the systems with positive variations, it is found that the rate of MT from less- to more-massive stars is a function of the luminosity ratio and/or mass ratio; the ML rate is a function of the secondary temperature. The discussion also addresses possible processes occurring in the sample binaries.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"123 ","pages":"Article 102495"},"PeriodicalIF":2.1,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520956","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}
Pub Date : 2025-11-05DOI: 10.1016/j.newast.2025.102497
A.Y. Shaikh , A.P. Jenekar
The presented study prioritizes the exploration of the cosmic model that integrates Barrow holographic dark energy (BHDE) within the confines of gravity. The study proposes to resolve the field equations of the cosmic model by incorporating the temporal deceleration parameter (DP) in relation to the scale factor. We assessed the model's predictability using a Bayesian MCMC approach that draws on late-time cosmic observations, comprising 58 data values, and the SN Ia pantheon datasets involving 1048 data values, along with their combination, to set bounds around the free parameters. The Hubble threshold applies as an infrared (IR) threshold in the inspection of the BHDE. We thoroughly study the kinematical and physical aspects of the model. Our findings establish a seamless advance of the cosmos, moving from a decelerating era in earlier times to an accelerating era in both the immediate as well as distant future, as revealed by the trajectories of the equation of state , deceleration , jerk , snap , and lerk parameters. We investigate the phase diagnostics via statefinder and analysis. The insight of energy conditions (ECs) further substantiates the predominance of BHDE following a speeding up Universe, while the model’s stability is predicted by the parameter of squared speed of sound. We concluded that our study's results comply with existing observational evidence, proving that our model demonstrates an effective alternative interpretation for the Universe's observed acceleration by accurately capturing the emergence of energy components while preserving stability.
{"title":"Cosmological dynamics of barrow holographic dark energy in f(G) gravity: An analytical and observational approach","authors":"A.Y. Shaikh , A.P. Jenekar","doi":"10.1016/j.newast.2025.102497","DOIUrl":"10.1016/j.newast.2025.102497","url":null,"abstract":"<div><div>The presented study prioritizes the exploration of the cosmic model that integrates Barrow holographic dark energy (BHDE) within the confines of <span><math><mrow><mi>f</mi><mo>(</mo><mi>G</mi><mo>)</mo></mrow></math></span> gravity. The study proposes to resolve the field equations of the cosmic model by incorporating the temporal deceleration parameter (DP) in relation to the scale factor. We assessed the model's predictability using a Bayesian MCMC approach that draws on late-time cosmic observations, comprising 58 data values, and the SN Ia pantheon datasets involving 1048 data values, along with their combination, to set bounds around the free parameters. The Hubble threshold applies as an infrared (IR) threshold in the inspection of the BHDE. We thoroughly study the kinematical and physical aspects of the model. Our findings establish a seamless advance of the cosmos, moving from a decelerating era in earlier times to an accelerating era in both the immediate as well as distant future, as revealed by the trajectories of the equation of state <span><math><mrow><mo>(</mo><msub><mi>ω</mi><mi>b</mi></msub><mo>)</mo></mrow></math></span>, deceleration <span><math><mrow><mo>(</mo><mi>q</mi><mo>)</mo></mrow></math></span>, jerk <span><math><mrow><mo>(</mo><mi>j</mi><mo>)</mo></mrow></math></span>, snap <span><math><mrow><mo>(</mo><mi>s</mi><mo>)</mo></mrow></math></span>, and lerk <span><math><mrow><mo>(</mo><mi>l</mi><mo>)</mo></mrow></math></span> parameters. We investigate the phase diagnostics via statefinder and <span><math><mrow><mi>O</mi><mi>m</mi><mo>(</mo><mi>z</mi><mo>)</mo></mrow></math></span> analysis. The insight of energy conditions (ECs) further substantiates the predominance of BHDE following a speeding up Universe, while the model’s stability is predicted by the parameter of squared speed of sound. We concluded that our study's results comply with existing observational evidence, proving that our model demonstrates an effective alternative interpretation for the Universe's observed acceleration by accurately capturing the emergence of energy components while preserving stability.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"123 ","pages":"Article 102497"},"PeriodicalIF":2.1,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520882","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}
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