New Astronomy最新文献

{"title":"Escape from a rotating barred galaxy","authors":"Euaggelos E. Zotos ,&nbsp;Christof Jung","doi":"10.1016/j.newast.2024.102247","DOIUrl":"https://doi.org/10.1016/j.newast.2024.102247","url":null,"abstract":"<div><p>We study the dynamics in the outer regions of a rotating barred galaxy and in particular, we observe the escape of a test particle from the gravitational potential of the galaxy. The acceleration mechanism of the test particle is a close encounter with one of the ends of the bar with the right relative phase of the position of the bar. This is a possible mechanism for the creation of high-velocity stars, i.e. stars with an energy sufficient to escape from the galaxy. Our results suggest that good candidates for high-velocity stars accelerated by this mechanism are the old low-mass high-velocity stars moving close to the disc. We will encounter the asymptotic dynamics which leads naturally to the study of a type of Poincaré map which can be reinterpreted as a scattering map. Thereby an iterated scattering map enters the picture in a quite natural form. The present work is a supplement to previous work on the dynamics in the inner region of the same model.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"111 ","pages":"Article 102247"},"PeriodicalIF":2.0,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140879440","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":"Exploring the physical properties of the γ Dor binary star RX Dra with photometry and asteroseismology","authors":"Ping Li,&nbsp;Wen-Ping Liao,&nbsp;Qi-Huan Zeng,&nbsp;Qi-Bin Sun,&nbsp;Min-Yu Li","doi":"10.1016/j.newast.2024.102234","DOIUrl":"10.1016/j.newast.2024.102234","url":null,"abstract":"&lt;div&gt;&lt;p&gt;We model the TESS light curve of the binary system RX Dra, and also first calculate a lot of theoretical models to fit the g-mode frequencies previously detected from the TESS series of this system. The mass ratio is determined to be &lt;span&gt;&lt;math&gt;&lt;mi&gt;q&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;=0.9026&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;0032&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;0032&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt;. We newly found that there are 16 frequencies (F1–F7, F11–F20) identified as dipole g-modes, two frequencies (F21, F22) identified as quadrupole g-modes, and another two frequencies (F23, F24) identified as g-sextupole modes, based on these model fits. The primary star is newly determined to be a &lt;span&gt;&lt;math&gt;&lt;mi&gt;γ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; Dor pulsator in the main-sequence stage with a rotation period of about 5.7&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;7&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; days, rotating slower than the orbital motion. The fundamental parameters of two components are firstly estimated as follows: &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;=1.53&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;17&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;00&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; M &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;⊙&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;= 1.38&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;00&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;18&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; M &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;⊙&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;=7240&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;44&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;490&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; K, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;=6747&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;221&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;201&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; K, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;=1.8288&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;0959&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;0260&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; R &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;⊙&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;R&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;= 1.3075&lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;2543&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;0450&lt;/mn&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; R &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;⊙&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;L&lt;/mi&gt;&lt;/mrow&gt;&lt;","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"111 ","pages":"Article 102234"},"PeriodicalIF":2.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140791345","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":"f(R,A) gravity theory in Einstein space background and causality violation","authors":"Faizuddin Ahmed","doi":"10.1016/j.newast.2024.102245","DOIUrl":"10.1016/j.newast.2024.102245","url":null,"abstract":"<div><p>In this paper, we exploration a Petrov type-N vacuum solution to Einstein’s field equations, while incorporating a negative cosmological constant (<span><math><mrow><mi>Λ</mi><mo>&lt;</mo><mn>0</mn></mrow></math></span>) within the framework of modified gravity theories. This solution intriguingly accommodates closed time-like curves at a particular moment in time, effectively violates the causality condition, thus acts as a time-machine model. A key observation is that the determinant of the Ricci tensor <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msup></math></span> for this particular Einstein space metric differs from zero. This noteworthy finding suggests to the existence of an anti-curvature tensor defined <span><math><mrow><msup><mrow><mi>A</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msup><mo>=</mo><msubsup><mrow><mi>R</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup></mrow></math></span> and hence, an anti-curvature scalar <span><math><mrow><mi>A</mi><mo>=</mo><msub><mrow><mi>g</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msub><mspace></mspace><msup><mrow><mi>A</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msup></mrow></math></span>, which is introduced with the Lagrangian of the system, thereby giving rise to as Ricci-inverse gravity theory. We consider <strong>class-I</strong> models of Ricci-inverse gravity, where the function <span><math><mrow><mi>f</mi><mo>=</mo><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>A</mi><mo>)</mo></mrow><mo>=</mo><mrow><mo>(</mo><mi>R</mi><mo>+</mo><mi>κ</mi><mspace></mspace><mi>A</mi><mo>)</mo></mrow></mrow></math></span> with <span><math><mi>κ</mi></math></span> is the coupling constant. We demonstrate that this Einstein space metric serves as a vacuum solution with a negative modified cosmological constant within the framework of Ricci-inverse gravity. Consequently, the violation of causality persists within this new gravity theory as well. Moreover, we solve the modified field equations by considering matter content other than vacuum and demonstrate that the energy-density and isotropic pressure satisfies the equation <span><math><mrow><mi>ρ</mi><mo>=</mo><mo>−</mo><mi>p</mi><mo>=</mo><mfrac><mrow><mn>3</mn><mspace></mspace><mi>κ</mi></mrow><mrow><mi>Λ</mi></mrow></mfrac></mrow></math></span>.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"111 ","pages":"Article 102245"},"PeriodicalIF":2.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140778925","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 improved component masses and parallaxes for the two close binary stars: HD 80671 and HD 97038","authors":"Suhail Masda","doi":"10.1016/j.newast.2024.102244","DOIUrl":"10.1016/j.newast.2024.102244","url":null,"abstract":"&lt;div&gt;&lt;p&gt;We present the fundamental stellar parameters, including the individual component masses, as well as the orbital parameters, and dynamical parallaxes of the two close binary stars; HD&lt;!--&gt; &lt;!--&gt;80671, and HD&lt;!--&gt; &lt;!--&gt;97038. The stellar parameters are spectrophotometrically estimated via Al-Wardat’s method for analyzing binary and multiple stellar systems, which is having a combination of the spectroscopic analysis and the photometric analysis to build the combined and individual synthetic spectral energy distributions of the individual components of the systems and so to estimate their fundamental parameters, metallicities, and ages. It employs Kurucz’s model atmospheres of single stars, while the orbital parameters are estimated using Tokovinin’s method. The individual spectrophotometric component masses are inferred with good accuracy, and found to be &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;S&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt; = 1.47&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;⊙&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;S&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;29&lt;/mn&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;09&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;⊙&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; with an age of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;09&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; Gyr for HD&lt;!--&gt; &lt;!--&gt;80671, and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;S&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;A&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;17&lt;/mn&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;09&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;⊙&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;S&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;12&lt;/mn&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;08&lt;/mn&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;⊙&lt;/mo&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; with an age of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;981&lt;/mn&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;35&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; Gyr for HD&lt;!--&gt; &lt;!--&gt;97038. The improved dynamical parallaxes are given as &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;π&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;28&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;305&lt;/mn&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;45&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; mas for HD&lt;!--&gt; &lt;!--&gt;80671, and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;π&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;16&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;26&lt;/mn&gt;&lt;mo&gt;±&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;30&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; mas for HD&lt;!--&gt; &lt;!--&gt;97038. The evolutionary status of two binaries is discussed depending on the positions of the compo","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"111 ","pages":"Article 102244"},"PeriodicalIF":2.0,"publicationDate":"2024-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140772694","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":"Resolving the pulsation contents of 13 δ Scuti stars with TESS and K2","authors":"Ai-Ying Zhou","doi":"10.1016/j.newast.2024.102235","DOIUrl":"https://doi.org/10.1016/j.newast.2024.102235","url":null,"abstract":"<div><p>Using the <em>TESS</em> and <em>Kepler</em> K2 light curve archives, I have reanalyzed 13 known <span><math><mi>δ</mi></math></span> Scuti stars. AD Ari is now reclassified as a rotating ellipsoidal binary variable. EX Cnc and HD 73712 are reclassified as hybrid <span><math><mi>δ</mi></math></span> Sct-<span><math><mi>γ</mi></math></span> Dor pulsators. EX Cnc turns out to be an enticing asteroseismic target because of its three distinct groups of pulsation frequencies. The strong beating caused by two close frequencies is present in the star CD-54 7154. More than 71 pulsation frequencies were resolved for <span><math><mi>ι</mi></math></span> Boo and IT Dra with high significant levels, while V1821 Cyg, V2238 Cyg, BR Cnc, BU Cnc, and BV Cnc pulsate with a few dozen frequencies. In particular, K2 data revealed a significantly richer pulsational spectrum for the two <span><math><mi>δ</mi></math></span> Scuti stars BU Cnc and BV Cnc from six to 26. Unlike the other 12 stars, BN Cnc shows the simplest pulsation pattern. With high-precision and long-term space-based photometry, we are able to discern the pulsational contents of these stars more clearly and enhance our knowledge of them. This reanalysis using <em>TESS</em> and <em>Kepler</em> K2 data highlights the diversity of pulsational behavior among <span><math><mi>δ</mi></math></span> Scuti stars and the value of long-duration, high-precision photometry. Further asteroseismic modeling of these stars, particularly EX Cnc with its distinct frequency groups, promises to refine our understanding of their internal structures and pulsational mechanisms.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"111 ","pages":"Article 102235"},"PeriodicalIF":2.0,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140646292","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":"Particle motion around traversable wormholes: Possibility of closed timelike geodesics","authors":"Ayanendu Dutta ,&nbsp;Dhritimalya Roy ,&nbsp;Subenoy Chakraborty","doi":"10.1016/j.newast.2024.102236","DOIUrl":"https://doi.org/10.1016/j.newast.2024.102236","url":null,"abstract":"<div><p>The present work investigates the general wormhole solution in Einstein gravity with an exponential shape function around an ultrastatic and a finite redshift geometry. The geodesic motion around the wormholes is studied in which the deflection angle of the orbiting photon sphere is found to be negative after a certain region, indicating the presence of repulsive effect of gravity in both the ultrastatic and finite redshift wormholes. Various unbounded and bounded timelike trajectories are presented on the wormhole embedding diagrams, in which some of the bound orbits involve intersection points that may lead to causality violating geodesics. Another class of closed timelike geodesics are obtained in the unstable circular trajectory that appeared at the wormhole throat. Finally, the trajectories are classified in terms of the family of CTG orbits.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"111 ","pages":"Article 102236"},"PeriodicalIF":2.0,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140605221","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 study of the short period contact binary V415 Gem","authors":"Bin Zhang ,&nbsp;Yidan Gao","doi":"10.1016/j.newast.2024.102233","DOIUrl":"https://doi.org/10.1016/j.newast.2024.102233","url":null,"abstract":"<div><p>The photometric study of the short period contact binary V415 Gem are performed for the first time. We discovered that it is a W-subtype shallow contact binary with a mass ratio of q = 2.297 and a contact degree of f = 3.6%. The light curves of the target exhibit an O’Connell effect, we attached a cool star-spot on its primary component for better fitting results. At the same time, the third light was found during our analysis by using the 2015 version of the Wilson–Devinney (<span><math><mrow><mi>W</mi><mo>−</mo><mi>D</mi></mrow></math></span>) code. And the average luminosity contribution of the third light is 44% of the total light. Besides, the <span><math><mrow><mi>O</mi><mo>−</mo><mi>C</mi></mrow></math></span> curve of V415 Gem exhibits a cyclic variation, which is due to the light-travel time effect caused by the presence of a third component with an amplitude of 0.0033 days and a period of 11.5 years. The mass of the third body is estimated to be M<span><math><mrow><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub><mo>∼</mo><mn>1</mn><mo>.</mo><mn>08</mn></mrow></math></span>M<span><math><msub><mrow></mrow><mrow><mo>⊙</mo></mrow></msub></math></span>.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"111 ","pages":"Article 102233"},"PeriodicalIF":2.0,"publicationDate":"2024-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140554673","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":"ASIVA – Platform for observational and computational analysis of stellar variables","authors":"Parvej Reja Saleh ,&nbsp;Tanveer Singh ,&nbsp;Debasish Hazarika ,&nbsp;Surabhi Rajkumari ,&nbsp;Saurabh Rajkumar ,&nbsp;Pritam Das ,&nbsp;Padmakar Singh Parihar ,&nbsp;Eeshankur Saikia","doi":"10.1016/j.newast.2024.102232","DOIUrl":"https://doi.org/10.1016/j.newast.2024.102232","url":null,"abstract":"<div><p>The astronomical data analysis consists of two crucial process; data reduction of the captured images and data analysis of the derived magnitudes. We present the platform ASIVA, a data analysis platform which comes along with a data reduction pipeline. The data reduction pipeline gives flexibility to analyse the FITS images and also perform image alignment for detecting the correct image coordinates for required objects. It can be custom scheduled with cron jobs so that it picks the latest data and appends the results accordingly. The data analysis platform allows user to effectively analyse the ensemble data and perform accurate data processing and grouping with ease. It is integrated with a custom algorithm to detect the variable stars from an ensemble with its relative standard deviations. The statistical, spectral and non-linear dynamics features can be extracted from time series data which can be eventually used for in-depth analysis. To validate the capability, we have analysed 15 nights of Orion Nebula Cluster field in I filter which had 1585 images. ASIVA reduces manual effort to a great extent thus saves analysis time and excludes human errors.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"111 ","pages":"Article 102232"},"PeriodicalIF":2.0,"publicationDate":"2024-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140618276","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":"Charged anisotropic fluid sphere in f(Q) gravity satisfying Vaidya - Tikekar metric","authors":"Simranjeet Kaur ,&nbsp;S.K. Maurya ,&nbsp;Sacheendra Shukla ,&nbsp;B. Dayanandan","doi":"10.1016/j.newast.2024.102230","DOIUrl":"https://doi.org/10.1016/j.newast.2024.102230","url":null,"abstract":"<div><p>In this paper, we study the properties of electrically charged anisotropic and spherically symmetric compact stars in <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> gravity theory. The field equations have been solved using the MIT-Bag Equation of State (EoS) along with the Vaidya–Tikekar potential. However, the specific form of charge <span><math><mrow><msup><mrow><mi>E</mi></mrow><mrow><mn>2</mn></mrow></msup><mrow><mo>(</mo><mi>r</mi><mo>)</mo></mrow><mo>=</mo><mfrac><mrow><msub><mrow><mi>q</mi></mrow><mrow><mn>0</mn></mrow></msub><msup><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msup><msup><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow><mrow><msup><mrow><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>L</mi><msup><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)</mo></mrow></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfrac></mrow></math></span> has been used to study the charged compact star model. The interior charge anisotropic solution has been matched with the charged Schwarzchild-(Anti)-de-Sitter metric. In particular, this study has been conducted on different compact stars viz, EXO 1785-248, PSR J1614-2230, PSR J0740+620 and SMC X-1. The mass–radius ratio of these compact stars has been predicted, and the physical viability of the model has been checked through the behaviour of causality condition, matter variables, energy constraints, modified TOV equation, and adiabatic index of the star. In conclusion, we observe a well-behaved model of a compact star in <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></math></span> gravity with charged matter distribution.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"110 ","pages":"Article 102230"},"PeriodicalIF":2.0,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140547243","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 studies of the member eclipsing binary ZTFJ015003.88+534,734.1 in the newly discovered young open cluster UBC 188","authors":"Y.H.M. Hendy,&nbsp;I. Zead,&nbsp;A.E. Abdelaziz,&nbsp;A. Takey","doi":"10.1016/j.newast.2024.102231","DOIUrl":"https://doi.org/10.1016/j.newast.2024.102231","url":null,"abstract":"<div><p>We present the first CCD observations of an eclipsing binary, ZTFJ015003.88+534,734.1, which is a member in the open star cluster UBC 188. The observations were taken by the 1.88 m telescope at the Kottamia Astronomical Observatory (KAO) in SDSS <em>griz</em> bands. The latest version of the Wilson-Devinney (W-D) code was employed for photometric analysis and light curve modeling of the eclipsing binary. The results indicate that the binary system is in an over-contact configuration. The mass of the primary star (M1) is determined to be 1.293 M_⊙, and the mass of the secondary star (M2) is directly derived from the system's estimated mass ratio (<em>q</em> = M2/M1) as 0.340 times the solar mass (M_⊙). We investigated the color-magnitude diagram and the membership probability of the open cluster UBC 188 using the Gaia DR3 data. We determined the membership probability of the eclipsing binary ZTFJ015003.88+534,734.1 using the pyUPMASK algorithm and found that its membership probability is one.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"110 ","pages":"Article 102231"},"PeriodicalIF":2.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140347164","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}