New Astronomy最新文献

{"title":"The role of Finsler-Randers geometry in shaping anisotropic metrics and thermodynamic properties in black holes theory","authors":"J Praveen,&nbsp;S K Narasimhamurthy","doi":"10.1016/j.newast.2025.102404","DOIUrl":"10.1016/j.newast.2025.102404","url":null,"abstract":"<div><div>In this research paper, we delve into the study of black hole (BH) structure within the context of Finsler geometry, a novel approach not previously explored by other researchers. We focused on developing the Finsler-Randers metric tensor for black holes, with the aid of the Barthel connection along with the osculating Riemannian method. This newly derived metric demonstrates significant departures from the conventional black hole metrics found in General Relativity (GR) by the presence of Finslerian term <span><math><mi>η</mi></math></span>, thereby shedding new light on the geometry and nature of black holes. To comprehensively understand the characteristics of black holes, we calculated the metric components under both vacuum and non-vacuum conditions. Our findings indicate that the metric structure aligns well with the known Riemannian limits, reinforcing the compatibility of our model with established theories. Moreover, we extended our analysis to include the thermodynamics of black holes in a Finslerian framework in brief. The results from this exploration affirm that the fundamental laws of black hole thermodynamics remain valid, reinforcing the viability and consistency of our Finslerian model. This study not only contributes to our understanding of black hole physics but also opens new avenues for further research in the realm of Finsler geometry and its implications for astrophysics<strong>.</strong></div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"119 ","pages":"Article 102404"},"PeriodicalIF":1.9,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643106","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":"Evolution of neutron stars in wide eccentric low-mass binary systems","authors":"Marina Afonina ,&nbsp;Sergei Popov","doi":"10.1016/j.newast.2025.102401","DOIUrl":"10.1016/j.newast.2025.102401","url":null,"abstract":"<div><div>Precise astrometric measurement with <em>Gaia</em> satellite resulted in the discovery of tens of wide binary systems consisting of a Sun-like star and an invisible component. The latter can be a white dwarf, a neutron star, or a black hole. In this paper, we model magneto-rotational evolution of neutron stars in wide low-mass binaries accounting for the orbital eccentricity. We aim to calculate when neutron stars in such systems can start to accrete matter from the stellar wind of the companion. We show that the transition from the ejector to the propeller stage occurs earlier in more eccentric systems, thus increasing the time that neutron stars can spend accreting matter. Our calculations show that in the case of efficient spin-down at the propeller stage, a neutron star in an eccentric orbit with <span><math><mrow><mi>e</mi><mo>≳</mo><mn>0</mn><mo>.</mo><mn>6</mn></mrow></math></span> and a standard magnetic field <span><math><mrow><mi>B</mi><mo>=</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>12</mn></mrow></msup></mrow></math></span> G can start accreting within a few Gyr. For neutron stars with <span><math><mrow><mi>B</mi><mo>=</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>13</mn></mrow></msup></mrow></math></span> G the onset of accretion occurs earlier regardless of the orbital eccentricity. Otherwise, with a lower spin-down rate, such a neutron star will remain at the propeller stage for most of its life.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"119 ","pages":"Article 102401"},"PeriodicalIF":1.9,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631794","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":"The first CCD photometric study of the member eclipsing binary ZTF J060425.73+365000.1 in the newly discovered young open cluster UBC 68","authors":"Y.H.M. Hendy,&nbsp;Ahmed Shokry,&nbsp;Ali Takey,&nbsp;Mohamed S. Aboueisha","doi":"10.1016/j.newast.2025.102392","DOIUrl":"10.1016/j.newast.2025.102392","url":null,"abstract":"<div><div>Multi-band photometric observations of the contact binary system ZTF J060425.73+365000.1 (hereinafter ZTF 06+36) are conducted using the 1.88-meter telescope at Kottamia Astronomical Observatory (KAO), Cairo, Egypt. This study presents the first photometric measurements and light curve analysis of this binary system. Analysis using the Wilson-Devinney (W-D) program reveals that the ZTF 06+36 system is an overcontact A-subtype system with a fill-out factor of 0.15 and mass ratios (q) of 0.34. To understand its evolutionary status, we investigated mass-luminosity, mass-radius, and mass-temperature relations. These relations indicate that the primary component of the system is the main sequence star, whereas the less massive component has evolved beyond the main sequence. Additionally, Gaia DR3 data is utilized to analyze the binary system's position on the color-magnitude diagram and evaluate its membership in the open cluster UBC 68. We combined two methods of machine learning algorithms (HDBSCAN and pyUPMASK) to obtain reliable stellar members of the UBC 68. They confirmed that the eclipsing binary</div><div>ZTF 06+36 has a membership probability of 1, indicating it is a member of the cluster. We also determined the physical parameters of the open cluster (UBC 68). Its age log(age), reddening E(BP-RP), and photometric distance are estimated to be 8.41±0.33 yr, 0.46±0.03 mag, and 2259±115 pc, respectively.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"119 ","pages":"Article 102392"},"PeriodicalIF":1.9,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686668","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":"Transit timing variations of the sub-Saturn exoplanet HAT-P-12b","authors":"Kaviya Parthasarathy ,&nbsp;Hsin-Min Liu ,&nbsp;Ing-Guey Jiang ,&nbsp;Li-Chin Yeh ,&nbsp;Napaporn A-thano ,&nbsp;Supachai Awiphan ,&nbsp;Wen-Chi Cheng ,&nbsp;Devesh P. Sariya ,&nbsp;Shraddha Biswas ,&nbsp;Devendra Bisht ,&nbsp;Evgeny Griv ,&nbsp;David Mkrtichian ,&nbsp;Vineet Kumar Mannaday ,&nbsp;Parijat Thakur ,&nbsp;Aleksey Shlyapnikov","doi":"10.1016/j.newast.2025.102390","DOIUrl":"10.1016/j.newast.2025.102390","url":null,"abstract":"<div><div>We present Transit Timing Variations (TTVs) of HAT-P-12b, a low-density sub-Saturn mass planet orbiting a metal-poor K4 dwarf star. Using 14 years of observational data (2009–2022), our study incorporates 7 new ground-based photometric transit observations, three sectors of Transiting Exoplanet Survey Satellite (TESS) data, and 23 previously published light curves. A total of 46 light curves were analyzed using various analytical models, such as linear, orbital decay, apsidal precession, and sinusoidal models to investigate the presence of additional planets. The stellar tidal quality factor (<span><math><mrow><msubsup><mrow><mi>Q</mi></mrow><mrow><mo>⋆</mo></mrow><mrow><mo>′</mo></mrow></msubsup><mo>∼</mo></mrow></math></span> 28.4) is lower than the theoretical predictions, making the orbital decay model an unlikely explanation. The apsidal precession model with a χ<span><math><msubsup><mrow></mrow><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msubsup></math></span> of 4.2 revealed a slight orbital eccentricity (e = 0.0013) and a precession rate of 0.0045 rad/epoch. Frequency analysis using the Generalized Lomb–Scargle (GLS) periodogram identified a significant periodic signal at 0.00415 cycles/day (FAP = 5.1 × 10⁻⁶ %), suggesting the influence of an additional planetary companion. The sinusoidal model provides the lowest reduced chi-squared value (χ<span><math><msubsup><mrow></mrow><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msubsup></math></span>) of 3.2. Sinusoidal fitting of the timing residuals estimated this companion to have a mass of approximately 0.02 <span><math><msub><mrow><mi>M</mi></mrow><mrow><mi>J</mi></mrow></msub></math></span> , assuming it is in a 2:1 Mean-Motion Resonance (MMR) with HAT-P-12b. Additionally, the Applegate mechanism, with an amplitude much smaller than the observed TTV amplitude of 156 s, confirms that stellar activity is not responsible for the observed variations.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"119 ","pages":"Article 102390"},"PeriodicalIF":1.9,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143697566","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":"WASP-52b: Insights into the exoplanet’s parameters from combining new photometric ground observations and TESS observation with SOPHIE, COR, and HARPS data for multifilter photometric and spectroscopic radial velocity","authors":"Mohammad F. Talafha ,&nbsp;Abdelrazek M.K. Shaltout ,&nbsp;Ali G.A. Abdelkawy ,&nbsp;M.M. Beheary","doi":"10.1016/j.newast.2025.102379","DOIUrl":"10.1016/j.newast.2025.102379","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This paper is done in three steps, (A) exoplanet photometric Observation, (B) photometric, radial velocity, and transmission transit analysis by the RAW data with different software and open-source platforms, and (C) combines new photometric data (our observations and TESS data) with radial velocities data to bring insights into this planet, to compare our transit observations results with previously published and reanalyzed results. All these results test the ability of exoplanet observations using a small telescope aperture hosted in Sharjah Astronomical Observatory (SAO- M47) with a 431 mm diameter.&lt;/div&gt;&lt;div&gt;For that, we made eight new light curves for the WASP-52b exoplanet. The observations were obtained from the Sharjah Astronomical Observatory (M47, 0.431 m) during 2019 and 2023 using different filters R, V, and L. Using multiple software, we estimated the planet transit’s physical and orbital parameters from individual and folded light curves analysis and apply transit results with radial velocity observation by EXOFAST tool for generate the full parameters of the exoplanet depend on filters. First, we analyzed light curve transits in two ways, individually with different photometrical software and codes like Muniwin and Hops Master, for folded light curves we applied the TransitFit code. By photometric results, we have determined the radius of the planet (R), semi-major axis (a), inclination (&lt;em&gt;i&lt;/em&gt;), and period of transit time (P) for comparison with previous studies. For folded our observations, where we folded three observations by the L filter, three observations by the R filter, and two observations by the V filter. Also, for comparing exoplanet orbit parameters we relied upon different radial velocity observations collected from multi-source and public data archives we reexamined, merged, and utilized (RV) observation data by collecting open-source observations from many observatories archives like the Haute-Provence Observatory spectrograph (SOPHIE) new release data starting from 2010 to 2022, HARPS from HARPS RVBank archive and CORALIE (COR) spectrograph installed at The Swiss 1.2-metre Leonhard Euler Telescope at La Silla. Using the platform DACE we recalculate and reanalyze the Mass (M&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;), Period (P), and semi-major axis(a) of the exoplanet after combining the data and compare them with our photometric results generated by both software ( HOPS and TransitFit) results. Moreover, we reanalyzed the transmission transit observation data for the WASP-52b exoplanet taken in 2017 to comprehend the difference in transit depth between multifilter observation results. For that, we employed the PLanetary Atmospheric Transmission for Observer Noobs (PLATON) code to estimate the planet’s size with multi-filter observations for characterizing the atmospheric features that would affect the planetary transit depth and plot all previous transmission data lis","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"119 ","pages":"Article 102379"},"PeriodicalIF":1.9,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686667","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":"Parameterized Deceleration in f(Q,C) Gravity: A Logarithmic Approach","authors":"S.R. Bhoyar,&nbsp;Yash B. Ingole","doi":"10.1016/j.newast.2025.102386","DOIUrl":"10.1016/j.newast.2025.102386","url":null,"abstract":"<div><div>This study explores a novel logarithmic parameterization of the deceleration parameter within the <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow></mrow></math></span> gravity framework, incorporating a nonlinear functional form <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>=</mo><msub><mrow><mi>γ</mi></mrow><mrow><mn>1</mn></mrow></msub><msup><mrow><mi>Q</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>+</mo><msub><mrow><mi>γ</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>C</mi></mrow></math></span>, where <span><math><mi>Q</mi></math></span> and <span><math><mi>C</mi></math></span> denote the nonmetricity scalar and boundary term respectively and <span><math><mrow><mi>n</mi><mo>&gt;</mo><mn>1</mn></mrow></math></span>. This approach provides a distinctive perspective on the accelerated expansion of the universe without resorting to exotic fields. Using Observational Hubble Data (<span><math><mrow><mi>O</mi><mi>H</mi><mi>D</mi></mrow></math></span>) measurement and the <span><math><mrow><mi>P</mi><mi>a</mi><mi>n</mi><mi>t</mi><mi>h</mi><mi>e</mi><mi>o</mi><mi>n</mi><mo>+</mo><mi>S</mi><mi>H</mi><mn>0</mn><mi>E</mi><mi>S</mi></mrow></math></span> Type Ia supernovae dataset, the model parameters were restricted by a <span><math><msup><mrow><mi>χ</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> minimization technique. The analysis reveals a transition from deceleration to acceleration in the expansion history of the universe, with transition redshifts <span><math><mrow><msub><mrow><mi>z</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>≈</mo><mn>0</mn><mo>.</mo><mn>98</mn></mrow></math></span> (<span><math><mrow><mi>O</mi><mi>H</mi><mi>D</mi></mrow></math></span>) and <span><math><mrow><msub><mrow><mi>z</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>≈</mo><mn>0</mn><mo>.</mo><mn>76</mn></mrow></math></span> (<span><math><mrow><mi>P</mi><mi>a</mi><mi>n</mi><mi>t</mi><mi>h</mi><mi>e</mi><mi>o</mi><mi>n</mi><mo>+</mo><mi>S</mi><mi>H</mi><mn>0</mn><mi>E</mi><mi>S</mi></mrow></math></span>). The model demonstrates consistency with observations, offering insights into the dynamics of dark energy and alternative gravity theories while effectively modeling cosmic evolution across epochs.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"118 ","pages":"Article 102386"},"PeriodicalIF":1.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549350","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":"Impact on orbital period of X-ray binary systems attached to a cosmic string","authors":"Ishan Swamy,&nbsp;Deobrat Singh","doi":"10.1016/j.newast.2025.102378","DOIUrl":"10.1016/j.newast.2025.102378","url":null,"abstract":"<div><div>Cosmic strings attached to rotating black holes extract its rotational energy, resulting in a mass loss and reduced spin. In this paper we discuss the proposed methods to detect these phenomena and present a novel methodology based on existing literature, by considering a Low Mass X-ray binary system. We investigate the impact of a cosmic string interacting with a black hole in an X-ray binary system and attempt to explain the observations of unexpected orbital period changes in such systems by proposing mass loss by cosmic strings to be a potential cause. For a period change of order <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>10</mn></mrow></msup></mrow></math></span>, the string tension is <span><math><mrow><mo>∼</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>17</mn></mrow></msup></mrow></math></span>, lying in the predicted range for cosmic string tension. An analysis of multiple low mass X-ray binary systems is carried out and it is shown that a significant and observable change occurs for a string tension <span><math><mrow><mo>∼</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>11</mn></mrow></msup></mrow></math></span>.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"118 ","pages":"Article 102378"},"PeriodicalIF":1.9,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526989","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":"Thermal conduction and thermal-driven winds in magnetized viscous accretion disk dynamics","authors":"Biplob Sarkar ,&nbsp;Indu Kalpa Dihingia ,&nbsp;Ranjeev Misra","doi":"10.1016/j.newast.2025.102377","DOIUrl":"10.1016/j.newast.2025.102377","url":null,"abstract":"<div><div>This paper investigates the effects of saturated thermal conduction (TC) and thermal-driven winds (TDWs) on magnetized advection-dominated accretion onto a rotating black hole (BH). We incorporate dissipative processes in the magnetized accretion flow and expect the accretion disk to be threaded by predominantly toroidal and turbulent magnetic fields. We solve the magnetohydrodynamics equations and construct a self-consistent steady model of the magnetized accretion flow surrounding a rotating BH, which includes TC and TDWs. We seek global accretion solutions spanning from the BH horizon to a large distance and analyze the solution’s characteristics as a function of dissipation parameters. Accretion solutions with multiple critical points may exhibit shock waves if they meet the standing shock criteria. We found steady, global transonic, and shocked accretion solutions around the rotating BH. In particular, the wind parameter (<span><math><mi>m</mi></math></span>) and the saturated conduction parameter (<span><math><msub><mrow><mi>Φ</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>) significantly influence the dynamical behavior of shocks. The shock location moves away from the BH horizon as <span><math><msub><mrow><mi>Φ</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> and <span><math><mi>m</mi></math></span> increase, assuming fixed conditions at the disk’s outer edge. Our formalism explains the declining phase of BH outbursts, characterized by a monotonic decrease in QPO frequency as the burst decays. Based on our findings, we conclude that the combined effect of <span><math><msub><mrow><mi>Φ</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> and <span><math><mi>m</mi></math></span> parameters substantially alters the steady shock specific energy vs angular momentum parameter space and also modifies the corresponding post-shock luminosity vs QPO frequency parameter space. We propose, based on our theoretical model, that the <span><math><msub><mrow><mi>Φ</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> and <span><math><mi>m</mi></math></span> parameters may significantly influence the evolution of the BH outbursts.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"118 ","pages":"Article 102377"},"PeriodicalIF":1.9,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549349","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":"The discrepant long-term activities of the polars BY Camelopardalis and AR Ursae Majoris","authors":"Vojtěch Šimon","doi":"10.1016/j.newast.2025.102375","DOIUrl":"10.1016/j.newast.2025.102375","url":null,"abstract":"<div><div>Polars are cataclysmic variables with strongly magnetized white dwarfs (WDs). This analysis of the long-term optical activity of two polars (BY<!--> <!-->Cam and AR<!--> <!-->UMa) used the light curves of CCD data from the ZTF and CRTS and photographic data from the DASCH databases. These two polars display remarkably discrepant long-term activities. The high-state activity dominated BY<!--> <!-->Cam, except for a short and shallow low-state episode. A fit to BY<!--> <!-->Cam’s light curve shows long-term brightness changes in the high state. We ascribe the variable profiles of the histograms of the residuals of this fit (1-year bins) to the changes in the dominance of the individual accretion modes and accreting regions on the WD with time (hundreds of days). The high-state episodes (no matter how long and bright) of AR<!--> <!-->UMa occurred from a relatively stable low-state brightness level. The superorbital changes of AR<!--> <!-->UMa dominated in the high states. <strong>Bursts of mass transfer from the donor are likely to contribute to the short high-state episodes.</strong></div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"118 ","pages":"Article 102375"},"PeriodicalIF":1.9,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487068","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":"Investigation of the correlation between geomagnetic storms and cosmic ray intensity as well as cosmic ray intensity variation with solar wind parameters during three consecutive solar cycles 23, 24, and 25","authors":"Nisha Kohli ,&nbsp;Suman Garia ,&nbsp;Deepak Pandey ,&nbsp;Meena Pokharia ,&nbsp;Megha Agari","doi":"10.1016/j.newast.2025.102387","DOIUrl":"10.1016/j.newast.2025.102387","url":null,"abstract":"<div><div>A systematic correlation study has been performed in order to establish a significant association between CRI (cosmic ray intensity) and the following parameters: flow pressure, solar wind speed, plasma proton density, solar wind plasma temperature, and IMF (interplanetary magnetic field) for solar cycles 23 and 24, as well as the most recent solar cycle 25. To do this, we used a Chree analysis by superposed-epoch technique to investigate the link between hour-to-hour changes of CRI and the above-mentioned parameters. We found that there is a strong link between CRI and solar wind speed when compared to IMF. This suggests that solar wind speed is a more capable parameter than IMF to cause a decline in CRI. It was observed that for all three solar cycles, there is an inverse correlation between IMF and solar wind speed and a positive correlation between Dst and CRI. We found that solar wind plasma temperature, flow pressure, and plasma proton density have weak correlations with CRI, making them ineffective for CRs (cosmic rays). For all three solar cycles' intense and severe storms, we have discovered a very interesting and adequate result: maximum decline in CRI is observed on the days of minimal Dst (0–11hrs), IMF maximum (0–19hrs), and peak solar wind speed (0–15hrs). We discovered that the instantaneous modulation of CRI is caused by both the solar wind speed and the IMF. Notable behavior was displayed in the years 1999, 2000, 2004, 2014, 2016 2018, and 2023.</div></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"118 ","pages":"Article 102387"},"PeriodicalIF":1.9,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519685","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}