Astrophysical Bulletin最新文献

{"title":"Radio Sources of the Survey on the Declination\u0000of the Pulsar in the Crab Nebula ((mathbf{Dec}boldsymbol{=+22}^{boldsymbol{circ}}))","authors":"A. A. Kudryashova,&nbsp;N. N. Bursov,&nbsp;S. A. Trushkin","doi":"10.1134/S1990341324700263","DOIUrl":"10.1134/S1990341324700263","url":null,"abstract":"<p>The results of the analysis of 205 brightest sources (<span>(S&gt;15)</span> mJy),\u0000which were found in the sky survey at the declination of the\u0000pulsar in the Crab Nebula, are presented. The survey was conducted\u0000at a frequency of 4.7 GHz using a three-beam radiometer complex\u0000installed in the focus of the Western Sector of the RATAN-600\u0000radio telescope in 2018–2019. Based on the measurements taken and\u0000the data collected in the CATS astrophysical catalogs database,\u0000the radio spectra of the objects were constructed. For a quarter\u0000of all detected sources, data at frequencies above 4 GHz were\u0000obtained for the first time, and for the rest they were\u0000supplemented. The variability of radiation sources on the scales\u0000of the year, from days to months, has been studied. The greatest\u0000change in the radio flux was found in the blazar B2 1324<span>(+)</span>22. The\u0000search for daily variability was carried out for 26 of the\u0000brightest sources with an average value of <span>(S_{4.7}sim 250)</span> mJy.\u0000All sources are identified with objects from\u0000optical and infrared catalogs. The radio luminosity was calculated\u0000for 112 objects with known redshifts.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"79 1","pages":"36 - 59"},"PeriodicalIF":1.3,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140932538","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 Estimating the Masses of Star Clusters Embedded in Clouds of Interstellar Gas and Dust","authors":"V. M. Danilov","doi":"10.1134/S1990341323600321","DOIUrl":"10.1134/S1990341323600321","url":null,"abstract":"<p>In the article, a method is developed for estimating the dynamic masses of the stellar and gas components of cluster-cloud systems under conditions of non-isolation and significant non-stationarity of stellar and gas subsystems in a regular field. A number of estimates of the dynamic masses of the stellar and gas components of the system are made without using the virial theorem for zero and positive values of the total energies <span>(E)</span> of the system as a whole and <span>(E_{2})</span> of its gaseous subsystem. The well-known estimates of the free-fall time <span>(tau_{textrm{ff}})</span> for fragments in the force field of a sphere of uniform and inhomogeneous density sphere simulating a system of gas and stars are refined. The estimates of the <span>(tau_{textrm{ff}})</span> quantities are supplemented by estimates of the radial velocities <span>(v_{r})</span> of the fragments in such systems. A number of relations between the parameters of the stellar and gas subsystems in the considered models of embedded clusters are obtained. It is shown that instead of one virial coefficient to describe the system, it is necessary to use three coefficients, the formulas for which are given. The relations make it possible to estimate the dynamic masses of non-isolated and non-stationary subsystems from data on the structural-dynamic characteristics of an embedded cluster. It is shown that the ratio <span>({overline{v}}_{c,1}^{2}/sigma_{1,v}^{2}&gt;4)</span>, where <span>(sigma_{1,v}^{2})</span> is the mean square of the velocities of the stellar subsystem in the case of its virial equilibrium, and <span>({overline{v}}_{c,1}^{2})</span> is the mean square of the critical velocities of the stars in this subsystem. It is shown that embedded clusters with parameters <span>(x=R_{1}/R_{2})</span> and <span>(mu=M_{1}/M_{2})</span> have maximum values <span>({overline{v}}_{c,1}^{2}/sigma_{1,v}^{2})</span> along some curve in the <span>((x,mu))</span> space (<span>(M_{i})</span> and <span>(R_{i})</span> are the mass and radius of the <span>(i)</span>th subsystem). The embedded clusters with parameters <span>((x,mu))</span> close to this curve are the least susceptible to destruction space relaxation processes. It is shown that, depending on the initial energies <span>(E)</span> and <span>(E_{2})</span>, the masses of a subsystem of stars in an embedded cluster can be much smaller than the virial masses of this subsystem. This result is also of particular interest for estimating the dynamic masses of galaxy clusters. It is noted that an increase in the degree of non-stationarity of the considered models of embedded clusters leads to a decrease in the periods of oscillations of the stellar subsystem.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"79 1","pages":"71 - 87"},"PeriodicalIF":1.3,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140932547","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":"Velocity Dispersion and H(boldsymbol{alpha})-emission of Ionized Gas in Star-forming Regions","authors":"E. O. Vasiliev,&nbsp;Yu. A. Shchekinov","doi":"10.1134/S1990341323600242","DOIUrl":"10.1134/S1990341323600242","url":null,"abstract":"<p>To understand the nature of gas flows in star-forming regions of nearby galaxies, the relationship between the surface brightness values in the H<span>(alpha)</span> line and the velocity dispersion of ionized gas, known as the ‘‘surface brightness–velocity dispersion’’ diagram, is often used. Based on three-dimensional gas-dynamic calculations, we examined the evolution of synthetic diagrams for supershells formed as a result of multiple supernova explosions in a star cluster located in the galactic disk. Based on the results of a study of changes in the shape and structure of the diagram depending on the gas density, its metallicity, and the disk scale height, it is possible to identify ranges of values in the diagram that are characteristic of young bubbles developing in dense or rarefied gas at large heights above the plane of the disk. We found that the structure of the diagram depends on the age of the supershells and the physical properties of the gas in the disk. For nearby dwarf galaxies, the structure of the observed ‘‘surface brightness–velocity dispersion’’ diagrams can only be explained by describing the dynamics of bubbles formed by multiple SN explosions in small star clusters of different ages.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"79 1","pages":"60 - 70"},"PeriodicalIF":1.3,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140932540","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":"Progress in Supernovae Studies with the 2.5-m Telescope at the Caucasus Mountain Observatory of SAI MSU","authors":"D. Yu. Tsvetkov,&nbsp;N. N. Pavlyuk,&nbsp;V. A. Echeistov,&nbsp;P. V. Baklanov","doi":"10.1134/S1990341323700232","DOIUrl":"10.1134/S1990341323700232","url":null,"abstract":"<p>We present photometric and spectrocsopic observations of supernovae carried out with the 2.5-m telescope of the Caucasus Mountain Observatory of SAI MSU. The light curves for the objects 2017egm, 2017eaw, 2018cow, 2018aoq, 2018zd, 2019yvr, 2019vxm, 2020tlf, and 2020xtz were constructed and their basic parameters were determined. The observed light curves are compared to the theoretical calculations for SNe II-P 2017eaw and 2018aoq. The spectra of SNe 2019vxm, 2019yvr, 2020tlf, 2020xtz are presented. The profiles of emission lines are studied for SNe IIn 2019vxm and 2020tlf. Spectral modeling was carried out for SNe 2019yvr and 2020xtz. The results of the program of prompt SNe spectral classification for eight objects are reported.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"78 4","pages":"514 - 534"},"PeriodicalIF":1.3,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic Fields in Chemically Peculiar and Related Stars. IX. Main Results Obtained in 2022 and an Analysis of Immediate Prospects","authors":"I. I. Romanyuk","doi":"10.1134/S1990341323700244","DOIUrl":"10.1134/S1990341323700244","url":null,"abstract":"<p>We review the stellar magnetism studies published in 2022.\u0000We analyzed a total of 75 papers, which focus mostly on the study of\u0000magnetic fields in chemically peculiar and active\u0000cool stars. In the latter, migration of magnetic spots and change\u0000of their configuration is observed. Projects of spectrographs and\u0000spectropolarimeters for new big telescopes are also presented.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"78 4","pages":"594 - 605"},"PeriodicalIF":1.3,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019430","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":"Results of Magnetic Field Measurements with the 6-m BTA Telescope. IX. Observations in 2015","authors":"I. I. Romanyuk,&nbsp;A. V. Moiseeva,&nbsp;E. A. Semenko,&nbsp;I. A. Yakunin,&nbsp;D. O. Kudryavtsev","doi":"10.1134/S1990341323700207","DOIUrl":"10.1134/S1990341323700207","url":null,"abstract":"<p>The paper presents magnetic field measurements and physical\u0000parameters for 96 stars. Observations were carried out in 2015\u0000with the 6-m BTA telescope using the Main Stellar Spectrograph\u0000(MSS). By analyzing circularly polarized spectra, the magnetic\u0000fields of the stars HD 653, HD 8855, HD 94603, HD 188101\u0000(KIC 6065699), HD 189160,\u0000HD 195464, and BD+44<span>({}^{circ})</span> 4130 were discovered for the first time.\u0000No systematic measurement errors were detected.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"78 4","pages":"567 - 587"},"PeriodicalIF":1.3,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019460","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 M-dwarf L 98-59 and Atmospheric Escape of its Exoplanets","authors":"I. S. Savanov","doi":"10.1134/S1990341323700165","DOIUrl":"10.1134/S1990341323700165","url":null,"abstract":"<p>A study of the activity of a bright M-dwarf L 98-59, located at a distance of 10.6 pc from Earth is reported. The star has a multiplanetary system, where one of the planets, L 98-59 b, is a rocky planet with a mass not exceeding the mass of Venus. It was found that the level of chromospheric activity of L 98-59 does not exceed the average value characteristic of other cold dwarfs with similar color index values <span>((B-V))</span>. This level is below solar, the mean <span>(log R{{}^{prime}}_{textrm{HK}})</span> parameter for L 98-59 is equal to <span>(-)</span>5.297 dex. The data about the parent star and its activity was used to estimate the magnitude of the atmospheric escape of five planets (including the planet candidate 05). To calculate the loss of matter from the planetary atmospheres (without a detailed modeling of the processes in the ‘‘star–planet’’ system), we applied an approximation formula corresponding to the energy-limited atmospheric loss model. Estimates of the XUV photon flux—extreme ultraviolet (EUV) and X-ray photons for the medium and high activity levels, as well as the estimates of the tidal parameter <span>(K_{textrm{tide}}(xi))</span> were found. Variations of the <span>(dot{M})</span> parameter have been specified for five planets of the L 98-59 system, taking into account the possible activity level variations of the star. The <span>(dot{M})</span> parameter variations for planets c–e range from <span>(7.6times 10^{6})</span> g s<span>({}^{-1})</span> to <span>(3.8times 10^{7})</span> g s<span>({}^{-1})</span> (average activity level) and <span>(1.2)</span>–<span>(5.7times 10^{7})</span> g s<span>({}^{-1})</span> (high activity level). For the planet L 98-59 b, the an analogue of Venus, we got the following estimates: <span>(1.3times 10^{7})</span> and <span>(2.0times 10^{7})</span> g s<span>({}^{-1})</span> (for the intermediate and high activity levels, respectively). It can be assumed that the relatively modest outflow of matter from their atmospheres <span>(dot{M})</span>, despite the proximity of the planets to their star, is due to a small flux of XUV photons from the star due to the low level of its activity.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"78 4","pages":"588 - 593"},"PeriodicalIF":1.3,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019422","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":"Optical and X-ray Variability of (gamma) Cas Stars: HD 45995","authors":"A. F. Kholtygin,&nbsp;I. A. Yakunin,&nbsp;M. A. Burlak,&nbsp;E. B. Ryspaeva","doi":"10.1134/S199034132360031X","DOIUrl":"10.1134/S199034132360031X","url":null,"abstract":"<p>The paper is devoted to the analysis of the variability of the <span>(gamma)</span> Cas-type star HD 45995 in both optical and X-ray ranges. The variability of the line profiles of HD 45995 has been detected both for long (350–380 days) and short (11–87 minutes) time ranges. Based on the photometric light curves of HD 45995 obtained with the TESS satellite, we refined the rotation period of the star at <span>(P=0.8443pm 0.0009)</span> days. These light curves reveal components with periods of about 11<span>({{}^{textrm{h}}})</span> typical for non-radial pulsations of B stars and components with periods of about 4–14 days, the nature of which is still unknown. We must note, that the latter components may be of an instrumental character, for example, due to the satellite drift. The pattern of the photometric variability, according to the TESS data, changes significantly for different observation epochs in 2018/2019 and 2020/2021. In the X-ray light curves of HD 45995, the presence of superfast variations with a period of <span>(P=48.5pm 0.5)</span>seconds is suspected.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"78 4","pages":"557 - 566"},"PeriodicalIF":1.3,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019423","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":"Spectral Types of Long-Period Double-Lined Eclipsing Binary System Components from Low-Resolution Spectroscopy Data","authors":"A. Yu. Kniazev,&nbsp;I. Yu. Katkov,&nbsp;O. Yu. Malkov,&nbsp;L. N. Berdnikov,&nbsp;N. I. Shatsky,&nbsp;A. V. Dodin,&nbsp;S. G. Zheltouhov,&nbsp;I. A. Strahov","doi":"10.1134/S1990341323700177","DOIUrl":"10.1134/S1990341323700177","url":null,"abstract":"<p>We present the results of spectral observations and consequent analysis of six long-period double-lined eclipsing binaries (DLEBs) with main-sequence (MS) components from a sample formed with the aim of testing the ‘‘mass–luminosity’’ relation (MLR) for stars in the <span>(M/M_{odot}&gt;1.5)</span> mass range. We analyzed all the obtained spectra using a technique that allows one to reveal the binary nature of the system and determine <span>(T_{textrm{eff}})</span> and <span>(log g)</span> for each component, as well as the system metallicity [Fe/H] and line-of-sight extinction <span>(E(B-V))</span>. We computed the absolute parameters of the systems under consideration. An analysis of the obtained spectra shows that for three of the six objects (V1156 Cyg, EU Gem and V733 Per) we can clearly establish their binary nature and determine the spectral type and class for each component. Both components of the V733 Per system have already left the MS, and therefore the system must be excluded from our sample, whereas studies of V1156 Cyg and EU Gem should continue. OT And did not demonstrate a binary spectrum, however, the main component of the system is a hot A6 V star, and therefore, OT And should remain in our sample. We also revealed no binarity in the IM Del and LX Gem systems. Their brighter components turned out to be a cool giant and a supergiant, and these systems should be excluded from the sample based on the results of our analysis. We used the same technique to analyze the two spectra obtained for systems EU Gem and LX Gem using LAMOST. We have shown that the parameters determined from LAMOST spectra are in good agreement with the parameters determined for spectra obtained at the Caucasian Mountain Observatory (CMO) of SAI MSU. Our analysis allowed us to plot a first approximation of the V1156 Cyg velocity curves and show that the cool component in this system has a larger mass.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"78 4","pages":"535 - 549"},"PeriodicalIF":1.3,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019427","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":"ESPriF: the Echelle-Spectropolarimeter of the BTA Primary Focus. Correction of Low-Frequency Variations in the Star Image","authors":"M. V. Yushkin,&nbsp;E. V. Emelianov,&nbsp;Yu. B. Verich,&nbsp;V. E. Panchuk","doi":"10.1134/S1990341323700220","DOIUrl":"10.1134/S1990341323700220","url":null,"abstract":"<p>The development of a corrector for low-frequency variations in the star image at the input of ESPriF—the echelle spectropolarimeter of the BTA primary focus—is reported. New technical solutions have made it possible to extend the operating frequency range to 10 Hz for stars brighter than <span>(13^{mathrm{m}})</span>.</p>","PeriodicalId":478,"journal":{"name":"Astrophysical Bulletin","volume":"78 4","pages":"613 - 621"},"PeriodicalIF":1.3,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140019454","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}