Astronomy Letters-A Journal of Astronomy and Space Astrophysics最新文献

{"title":"Influence of Space Curvature on the Moment of Inertia of a Pulsar Magnetic Field","authors":"A. A. Matevosyan,&nbsp;D. P. Barsukov","doi":"10.1134/S1063773723100043","DOIUrl":"10.1134/S1063773723100043","url":null,"abstract":"<p>We consider the influence of space curvature in the Schwarzschild metric on the contribution of the magnetic field outside the neutron star to the moment of inertia of a radio pulsar. Our consideration is restricted only to the simplest configuration of the magnetic field, when it can be described by only one harmonic. We show that at a fixed magnetic field strength on the stellar surface the influence of space curvature reduces the contribution of the magnetic field outside the star to the departure of the inertia tensor from the spherical one several-fold.</p>","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"49 10","pages":"560 - 566"},"PeriodicalIF":1.1,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139968509","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":"Search for Rotating Radio Transients in the Pushchino Multibeam Survey","authors":"S. A. Tyul’bashev,&nbsp;M. A. Kitaeva,&nbsp;E. A. Brylyakova,&nbsp;V. S. Tyul’bashev,&nbsp;G. E. Tyul’basheva","doi":"10.1134/S1063773723090062","DOIUrl":"10.1134/S1063773723090062","url":null,"abstract":"<p>We have searched for pulse emission at 111 MHz toward 116 RRAT candidates. For our search we used the archival data obtained at the meridian 128-beam Large Phased Array radio telescope. About six days of observations in an interval of eight years were accumulated for each candidate. Eleven new RRATs were detected. We managed to estimate the periods for six of them and to construct the average profiles for four RRATs. Some of the candidates turned out to be known pulsars observed in the side lobes of the radio telescope and interference. For some of the candidates we failed to find any pulses with a signal-to-noise ratio greater than seven, and their nature remains unknown.</p>","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"49 10","pages":"533 - 539"},"PeriodicalIF":1.1,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139968645","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":"Hydrodynamical Simulation of the Structure of the X-Ray Pulsar Accretion Channel: Accounting for Resonant Scattering","authors":"I. D. Markozov,&nbsp;A. D. Kaminker,&nbsp;A. Y. Potekhin","doi":"10.1134/S1063773723100031","DOIUrl":"10.1134/S1063773723100031","url":null,"abstract":"<p>A self-consistent radiation-hydrodynamics model of an accretion channel of subcritical X-ray pulsars is constructed. The influence of the presence of resonance in the scattering cross-section on the accretion process and radiation transfer is taken into account. It is shown that the efficiency of plasma deceleration by radiation depends on the magnitude of the magnetic field <span>(B)</span>. For <span>(B=1.7times 10^{12})</span> G, the spectra and the degree of linear polarization of the radiation of the accretion channel are constructed. In the obtained spectra, the shape of the cyclotron line depends on the direction of the outgoing radiation. The calculated linear polarization degree of the outgoing radiation is <span>(30{-}40%)</span> near the cyclotron resonance, whereas it can be small (<span>({lesssim}5{-}10%)</span>) at energies significantly lower than the resonant one.</p>","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"49 10","pages":"583 - 590"},"PeriodicalIF":1.1,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139968518","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":"On the Influence of Magnetic Turbulence on the Spectra of Gamma-Ray Burst Afterglows","authors":"Yu. A. Uvarov,&nbsp;A. M. Bykov","doi":"10.1134/S1063773723100079","DOIUrl":"10.1134/S1063773723100079","url":null,"abstract":"<p>Gamma-ray bursts (GRBs) are the phenomena of rapid energy release of enormous power associated with the collapse or merging of stars. As a result of internal processes, populations of nonthermal accelerated particles radiating in a wide energy range are formed in them. A number of observations have shown that photons with energies up to tens of TeV are detected from some GRBs. However, due to the great energy losses of radiating particles, the explanation of this high-energy radiation in terms of standard radiation mechanisms runs into great difficulties. In this paper, based on the model of adiabatic expansion for the GRB afterglow phase, we investigate the influence of magnetic inhomogeneities on the spectra within the electron and proton synchrotron radiation mechanism by taking into account the Compton scattering of synchrotron photons. We show that the magnetic inhomogeneity effect can increase the maximum energies of the synchrotron radiation from electrons and protons several fold without affecting the maximum energies of the Compton photons being produced in the Klein–Nishina regime.</p>","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"49 10","pages":"591 - 597"},"PeriodicalIF":1.1,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139968569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Maneuver of Escape from the Vicinity of a Collinear Libration Point Using Light Pressure Forces","authors":"D. V. Shymanchuk,&nbsp;A. S. Shmyrov,&nbsp;V. A. Shmyrov","doi":"10.1134/S1063773723090050","DOIUrl":"10.1134/S1063773723090050","url":null,"abstract":"<p>The orbital motion of a spacecraft with a solar sail in the vicinity of the Sun–Earth collinear libration point is studied. The study is carried out within the Hill approximation of the circular restricted three-body problem. The collinear libration point is unstable, but instability can be a positive factor in the tasks of maneuvering in interplanetary space. This is because a small change in velocity near an unstable libration point can lead to a significant change in orbital motion. This property can be used in the development of projects to counteract the comet–asteroid hazard. A scheme for constructing the trajectories of interception of a spacecraft with a potentially hazardous object is proposed. One of the stages of this scheme, an optimal escape from the vicinity of the libration point using light pressure forces, is considered. The results of numerical simulations are presented.</p>","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"49 9","pages":"522 - 532"},"PeriodicalIF":1.1,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139645002","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":"Activity of the Young Solar Analog HD 109833 and Estimates of the Mass Loss Rate from the Atmospheres of Its Two Planets","authors":"I. S. Savanov","doi":"10.1134/S1063773723090049","DOIUrl":"10.1134/S1063773723090049","url":null,"abstract":"&lt;p&gt;We present the results of our analysis of the manifestations of activity in the young solar analog HD 109833 and estimate the mass loss rate from the atmospheres of its two planets. HD 109833 probably belongs to the Lower Centaurus Crux (LCC) association with an age of 27 &lt;span&gt;(pm)&lt;/span&gt; 3 Myr, but it is not inconceivable that the star is only spatially associated with the association and may be older, although in any case its age does not exceed 100–200 Myr. Based on data from the TESS archive for HD 109833, we have determined the stellar rotation period &lt;span&gt;(P=5.08pm 0.30)&lt;/span&gt; days and the photometric variability amplitude (about 0.6&lt;span&gt;({%})&lt;/span&gt; of the mean stellar brightness) and estimated the spot areas on its surface, which exceed the maximum sunspot area and are 15 200–17 700 m.s.h. Based on data from the All-Sky Automated Survey archive, we have revealed a stellar activity cycle with a duration &lt;span&gt;({sim}1950)&lt;/span&gt; days (5.3 years). Both planets in the HD 109833 system are characterized as sub-Neptunes with radii of 2.9 and 2.6 &lt;span&gt;(R_{oplus})&lt;/span&gt; and periods of 9.2 and 13.9 days. The mass loss rates by the planetary atmospheres have been found using an approximate formula corresponding to the energy-limited atmospheric escape model. To estimate the &lt;span&gt;(XUV)&lt;/span&gt; flux, we have applied analytical dependences relating the flux and the parameter &lt;span&gt;(log R^{prime}_{HK})&lt;/span&gt; and information about the distribution of these quantities for G-type stars, suggesting that there are two pronounced peaks with maxima for values &lt;span&gt;({sim}-5.0)&lt;/span&gt; and &lt;span&gt;(-4.5)&lt;/span&gt; dex in low-activity and active stars, respectively. In addition, we have used the relation between the X-ray flux from the star and &lt;span&gt;(log F_{XUV})&lt;/span&gt;. The value found is comparable to the estimate obtained by applying the parameter &lt;span&gt;(log R^{prime}_{HK})&lt;/span&gt; for active stars and exceeds it by a factor of 4. Both exoplanets HD 109833 b and c being considered by us fall into the region on the &lt;span&gt;((M-R))&lt;/span&gt; diagram in which the populations of rocky and volatile-rich exoplanets overlap and do not allow their masses to be estimated unambiguously. Our calculations were performed for two cases—rocky exoplanets and volatile-rich exoplanets. The masses of the exoplanets HD 109833 b and c are, respectively, 34.9 and 24 &lt;span&gt;(M_{oplus})&lt;/span&gt; for rocky exoplanets and 9.3 and 7.8 &lt;span&gt;(M_{oplus})&lt;/span&gt; for volatile-rich exoplanets. We present the results of our calculations of the atmospheric mass loss rates by the planets HD 109833 b and c while varying the parameters related to the estimates of the planetary masses and the UV flux incident on the planets. The parameter &lt;span&gt;(dot{M})&lt;/span&gt; for HD 109833 b and c varies in the ranges from &lt;span&gt;(9.60times 10^{7})&lt;/span&gt; to &lt;span&gt;(1.38times 10^{10})&lt;/span&gt; g s&lt;span&gt;({}^{-1})&lt;/span&gt; and from &lt;span&gt;(4.56times 10^{7})&lt;/span&gt; to &lt;span&gt;(5.28times 10^{9})&lt;/span&gt; g s&lt;span&gt;({}^{-1})&lt;/span&gt;","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"49 9","pages":"516 - 521"},"PeriodicalIF":1.1,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139645329","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":"Recurrent Symbiotic Nova T Coronae Borealis before Outburst","authors":"N. A. Maslennikova,&nbsp;A. M. Tatarnikov,&nbsp;A. A. Tatarnikova,&nbsp;A. V. Dodin,&nbsp;V. I. Shenavrin,&nbsp;M. A. Burlak,&nbsp;S. G. Zheltoukhov,&nbsp;I. A. Strakhov","doi":"10.1134/S1063773723090037","DOIUrl":"10.1134/S1063773723090037","url":null,"abstract":"<p>The results of photometric and spectral observations of T CrB obtained in a wide range of wavelengths in 2011–2023 are presented. We use the near-IR light curves to determine a new ephemeris <span>(JD_{textrm{min}}=2455828.9+227.55E)</span> for the times of light minima when the red giant is located between the observer and the hot component. The flux ratio H<span>(alpha)</span>/H<span>(beta)</span> varied from <span>({sim}3)</span> to <span>({sim}8)</span> in 2020–2023, which may be due to a change in the flux ratio between the X-ray and optical ranges. It is shown that the value of H<span>(alpha)</span>/H<span>(beta)</span> anticorrelates with the rate of accretion onto the hot component of the system. Based on high-speed follow-up observations obtained on June 8, 2023, we detected a variability of the He II <span>(lambda 4686)</span> line with a characteristic time-scale of <span>({sim}25)</span> min, the amplitude of variability in the <span>(B)</span>-band was <span>({sim}0overset{textrm{m}}{.}07)</span>. Simulations of the near-IR light curves accounting for the ellipsoidal effect allowed us to obtain the parameters of the binary system: the Roche lobe filling factor of the cool component <span>(mu=1.0)</span>, the mass ratio <span>(q=M_{textrm{cool}}/M_{textrm{hot}}in[0.5,0.77])</span>, the orbital inclination <span>(iin[55^{circ},63^{circ}])</span>. A comparison of the light curve obtained in 2005–2023 with the 1946 outburst template made it possible to predict the date of the upcoming outburst—January 2024.</p>","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"49 9","pages":"501 - 515"},"PeriodicalIF":1.1,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139645006","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":"Estimation of the Galactocentric Distance of the Sun from Cepheids Close to the Solar Circle","authors":"V. V. Bobylev","doi":"10.1134/S1063773723090025","DOIUrl":"10.1134/S1063773723090025","url":null,"abstract":"<p>Based on Cepheids located near the solar circle, we have determined the Galactocentric distance of the Sun <span>(R_{0})</span> and the Galactic rotation velocity at the solar distance <span>(V_{0})</span>. For our analysis we used a sample of <span>({sim})</span>200 classical Cepheids from the catalogue by Skowron et al. (2019), where the distances to them were determined from the period–luminosity relation. For these stars the proper motions and line-of-sight velocities were taken from the Gaia DR3 catalogue. The values of <span>(R_{0})</span> found lie within the range 7.8–8.3 kpc, depending on the heliocentric distance of the sample stars, on the adopted solar velocity relative to the local standard of rest, and on whether or not the perturbations caused by the Galactic spiral density wave are taken into account. The dispersion of the <span>(R_{0})</span> estimates is <span>({sim})</span>2 kpc. Similarly, the values of <span>(V_{0})</span> lie within the range 240–270 km s<span>({}^{-1})</span> with a dispersion of the estimates of 70–90 km s<span>({}^{-1})</span>. We consider the following estimates to be the final ones: <span>(R_{0}=8.24pm 0.20)</span> kpc and <span>(V_{0}=268pm 8)</span> km s<span>({}^{-1})</span> found by taking into account the perturbations from the Galactic spiral density wave.</p>","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"49 9","pages":"493 - 500"},"PeriodicalIF":1.1,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139645328","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":"Strong Scattering Effects in the Emission of Soft Gamma-Ray Bursts","authors":"E. M. Urvachev,&nbsp;D. S. Shidlovski,&nbsp;S. I. Blinnikov,&nbsp;S. I. Glazyrin","doi":"10.1134/S1063773723080042","DOIUrl":"10.1134/S1063773723080042","url":null,"abstract":"<p>When a light beam enters a scattering-dominated medium, the radiation is isotropized. Part of the radiation goes backwards, leading to non-monotonicity in the radiation energy density profile inside this medium. There arises a local maximum at which the energy density at a scattering albedo <span>({sim}1)</span> is severalfold greater than that without scattering at the same extinction. This effect is studied numerically in one-dimensional and two-dimensional simulations. It is demonstrated that a local maximum of the radiation energy density arises in the medium, whose value depends on the optical depth of the region. This effect can manifest itself, for example, when the radiation from a gamma-ray burst (GRB) enters heated regions in the interstellar medium. The presence of scattering in the GRB radiation generation region, near the front of strong shocks, affects the radiation pattern. The structure of such shocks is remarkable for the presence of a preshock preheating tail. Strong scattering in this region leads to the escape of a significant fraction of the radiation sideways and backwards in the shock reference frame, forming additional tails in the angular distribution of GRB radiation after the relativistic transformation to the laboratory frame. This effect is also studied numerically in three-dimensional simulations.</p>","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"49 8","pages":"445 - 453"},"PeriodicalIF":1.1,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139482903","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":"Comparative Modeling of the 2012b Outburst of Supernova 2009ip","authors":"E. M. Urvachev,&nbsp;S. I. Blinnikov,&nbsp;S. I. Glazyrin,&nbsp;D. S. Shidlovski","doi":"10.1134/S1063773723080054","DOIUrl":"10.1134/S1063773723080054","url":null,"abstract":"<p>The September 2012 outburst of the type IIn supernova 2009ip was simulated using two independent codes, STELLA and FRONT. The <span>(UBVRI)</span> light curves obtained agree well with one another and with observational data. Special attention is given to the dynamics of the emerging dense shell, which determines the luminosity of the object and is used for the direct method of determining the distance to the supernova. Two-dimensional spectral radiation-hydrodynamics computations of the SN 2009ip model were carried out, which confirmed the conclusion about the stability of this shell on the times scales of the method application.</p>","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"49 8","pages":"454 - 464"},"PeriodicalIF":1.1,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139482412","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}