Pub Date : 2024-06-01DOI: 10.31725/0367-7966-2024-233-58-67
N. Silant'ev, G. Alekseeva, Yu.K. Ananjevskaya
The pass of polarized radiation in magnetized atmosphere is described by the system of connected radiative transfer equations for the Stokes parameters. At multiple scattering of radiation it is necessary to know how the change of the Stokes parameters between the cases of scattering occurs. The paper presents the explicit formulas describing the transformation of the Stokes parameters for the number of situations. These formulas describe directly the transformation of the Stokes parameters in optically thin circumstellar envelopes. The formulas for mutiply scattered radiation in the system of transfer equations take into account this transformation of the Stokes parameters. The basic parameter in all cases is x = ωB/ω = 0.933 × 10−8λ(μ)B(G), where ωB is cyclotron frequency of the electron rotation and ω is the frequency of monochromatic radiation.
{"title":"Calculation of the Stokes parameters at propagation of radiation in magnetized atmosphere","authors":"N. Silant'ev, G. Alekseeva, Yu.K. Ananjevskaya","doi":"10.31725/0367-7966-2024-233-58-67","DOIUrl":"https://doi.org/10.31725/0367-7966-2024-233-58-67","url":null,"abstract":"The pass of polarized radiation in magnetized atmosphere is described by the system of connected radiative transfer equations for the Stokes parameters. At multiple scattering of radiation it is necessary to know how the change of the Stokes parameters between the cases of scattering occurs. The paper presents the explicit formulas describing the transformation of the Stokes parameters for the number of situations. These formulas describe directly the transformation of the Stokes parameters in optically thin circumstellar envelopes. The formulas for mutiply scattered radiation in the system of transfer equations take into account this transformation of the Stokes parameters. The basic parameter in all cases is x = ωB/ω = 0.933 × 10−8λ(μ)B(G), where ωB is cyclotron frequency of the electron rotation and ω is the frequency of monochromatic radiation.","PeriodicalId":503631,"journal":{"name":"Publications of the Pulkovo Observatory","volume":"54 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141412727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.31725/0367-7966-2024-233-34-38
N. Ikhsanov, V.Yu. Kim, N. Beskrovnaya
We discuss manifestations of the accreting neutron star in the massive X-ray binary system OAO 1657-415. We estimate the mass transfer rate between the system components within a scenario of wind-fed accretion and show that the X-ray luminosity of the pulsar can be explained only under condition that the velocity of stellar wind of the massive component in the orbital plane of the system is in the interval 200–500 km/s.
我们讨论了大质量X射线双星系统OAO 1657-415中中子星吸积的表现形式。我们估算了风吸积情况下系统各部分之间的质量转移率，并表明脉冲星的 X 射线光度只有在系统轨道面上大质量部分的恒星风速在 200-500 公里/秒之间的条件下才能得到解释。
{"title":"On the estimate of the stellar wind velocity of the massive component in OAO 1657-415","authors":"N. Ikhsanov, V.Yu. Kim, N. Beskrovnaya","doi":"10.31725/0367-7966-2024-233-34-38","DOIUrl":"https://doi.org/10.31725/0367-7966-2024-233-34-38","url":null,"abstract":"We discuss manifestations of the accreting neutron star in the massive X-ray binary system OAO 1657-415. We estimate the mass transfer rate between the system components within a scenario of wind-fed accretion and show that the X-ray luminosity of the pulsar can be explained only under condition that the velocity of stellar wind of the massive component in the orbital plane of the system is in the interval 200–500 km/s.","PeriodicalId":503631,"journal":{"name":"Publications of the Pulkovo Observatory","volume":"2007 29","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141400412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.31725/0367-7966-2024-233-51-57
Z.M. Malkin
Pulkovo Observatory has been operating a permanent GNSS station PULK since 2002. This paper presents the results of preliminary analysis of the changes in the errors in the coordinates of the station over time, primarily after replacement of the receiver or antenna. Two accuracy estimates were applied: the formal error of the daily coordinate estimates and the noise component of the PULK coordinate series. In the first case, the median estimate was used, in the second, the Allan variance. As a result, it turned out that two receiver replacements in the first years of operation led to a noticeable decrease in the formal coordinate error, whereas subsequent receiver replacements, as well as both antenna replacements, showed no noticeable changes in this error. The magnitude of the noise component of the coordinate series did not change much during the entire observation period.
{"title":"Impact of the equipment change at the Pulkovo GNSS station PULK on results of observations","authors":"Z.M. Malkin","doi":"10.31725/0367-7966-2024-233-51-57","DOIUrl":"https://doi.org/10.31725/0367-7966-2024-233-51-57","url":null,"abstract":"Pulkovo Observatory has been operating a permanent GNSS station PULK since 2002. This paper presents the results of preliminary analysis of the changes in the errors in the coordinates of the station over time, primarily after replacement of the receiver or antenna. Two accuracy estimates were applied: the formal error of the daily coordinate estimates and the noise component of the PULK coordinate series. In the first case, the median estimate was used, in the second, the Allan variance. As a result, it turned out that two receiver replacements in the first years of operation led to a noticeable decrease in the formal coordinate error, whereas subsequent receiver replacements, as well as both antenna replacements, showed no noticeable changes in this error. The magnitude of the noise component of the coordinate series did not change much during the entire observation period.","PeriodicalId":503631,"journal":{"name":"Publications of the Pulkovo Observatory","volume":"32 26","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141414931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.31725/0367-7966-2024-233-1-28
A. Bajkova, A.A. Smirnov, V. Bobylev
We analyzed the regularity/chaoticity of the orbits of 45 globular clusters in the central region of the Galaxy with a radius of 3.5 kpc, which are subject to the greatest influence from an elongated rotating bar. Various analysis methods were used, namely, methods for calculating the maximum characteristic Lyapunov exponents, the method of Poincaré sections, the frequency method based on the calculation of fundamental frequencies, as well as the visual assessment method. Bimodality was discovered in the histogram of the distribution of positive Lyapunov exponents, calculated in the classical version, without renormalization of the shadow orbit, which makes it possible to implement a probabilistic method of GC classification. To construct the orbits of globular clusters, we used a gravitational potential model with a bar in the form of a triaxial ellipsoid, described in detail in the work of Bajkova et al., Izvestiya GAO in Pulkovo, 2023, 228, 1. The following bar parameters were adopted: mass 1010M⊙, semimajor axis length 5 kpc, bar viewing angle 25o, rotation speed 40 km s−1 kpc−1. To form the 6D-phase space required for orbit integration, the most accurate astrometric data to date from the Gaia satellite (EDR3) (Vasiliev, Baumgardt, 2021), as well as new refined average distances to globular clusters (Baumgardt, Vasiliev, 2021) were used. A classification is made of globular clusters with regular and chaotic dynamics. As the analysis showed, globular clusters with small pericentric distances and large eccentricities are most susceptible to the influence of the bar and demonstrate the greatest chaos. It is shown that the results of classifying globular clusters by the nature of their orbital dynamics, obtained using the various methods of analysis considered in the work, correlate well with each other.
{"title":"Analysis of regularity/chaoticity of the Globular ckusters dynamics in the central region of the Milky Way","authors":"A. Bajkova, A.A. Smirnov, V. Bobylev","doi":"10.31725/0367-7966-2024-233-1-28","DOIUrl":"https://doi.org/10.31725/0367-7966-2024-233-1-28","url":null,"abstract":"We analyzed the regularity/chaoticity of the orbits of 45 globular clusters in the central region of the Galaxy with a radius of 3.5 kpc, which are subject to the greatest influence from an elongated rotating bar. Various analysis methods were used, namely, methods for calculating the maximum characteristic Lyapunov exponents, the method of Poincaré sections, the frequency method based on the calculation of fundamental frequencies, as well as the visual assessment method. Bimodality was discovered in the histogram of the distribution of positive Lyapunov exponents, calculated in the classical version, without renormalization of the shadow orbit, which makes it possible to implement a probabilistic method of GC classification. To construct the orbits of globular clusters, we used a gravitational potential model with a bar in the form of a triaxial ellipsoid, described in detail in the work of Bajkova et al., Izvestiya GAO in Pulkovo, 2023, 228, 1. The following bar parameters were adopted: mass 1010M⊙, semimajor axis length 5 kpc, bar viewing angle 25o, rotation speed 40 km s−1 kpc−1. To form the 6D-phase space required for orbit integration, the most accurate astrometric data to date from the Gaia satellite (EDR3) (Vasiliev, Baumgardt, 2021), as well as new refined average distances to globular clusters (Baumgardt, Vasiliev, 2021) were used. A classification is made of globular clusters with regular and chaotic dynamics. As the analysis showed, globular clusters with small pericentric distances and large eccentricities are most susceptible to the influence of the bar and demonstrate the greatest chaos. It is shown that the results of classifying globular clusters by the nature of their orbital dynamics, obtained using the various methods of analysis considered in the work, correlate well with each other.","PeriodicalId":503631,"journal":{"name":"Publications of the Pulkovo Observatory","volume":"127 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141406159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.31725/0367-7966-2024-233-39-50
K. Lobanova, A. V. Melnikov
By means of numerical experiments, the influence of the value of the asteroid’s own rotational velocity, orientation of the axis of rotation, and figure parameters on the magnitude of perturbations in its rotational dynamics arising during close approach to the Earth is studied. Two cases are considered: 1) asteroid (99942) Apophis with a relatively slow rotation (period ≈ 30 h) and 2) asteroid 2012 TC4, which has a fast rotation (period ≈ 12 min). It was found that in the case of asteroids with slow rotation, perturbations can be large: in the case of Apophis, when approaching the Earth in 2029, changes in the rotational period ∆P may reach tens of hours, and deviations in the orientation of the axis of rotation ∆γ — tens of degrees. For fast-rotating asteroids, the perturbations are very small: in the case of asteroid 2012 TC4 at its approach to the Earth in 2017, |∆P | < 10−5 min, |∆γ| < 0.01◦. It is shown that for asteroids with slow rotation, the uncertainty in the determination of asteroid figure parameters (moments of inertia) can lead to noticeable inaccuracies in the estimation of perturbation magnitudes. The uncertainty in the knowledge of the figure parameters of a fast-rotating asteroid practically does not affect the estimation of perturbations in its rotational dynamics. In the case of Apophis, changes in the rotational velocity and orientation of the axis of rotation during the upcoming 2029 approach to the Earth may lead to a decrease in the value of the parameter A2, which characterizes the Yarkovsky effect, to −1.5 · 10−14 a.u./d2, or to an increase up to −3.5 · 10−14 a.u./d2. Perturbations in the rotational dynamics of asteroid 2012 TC4 during its approach to the Earth in 2017 did not affect the value of parameter A2.
{"title":"The influence of the rotation speed and shape of an asteroid on the magnitude of disturbances in its rotational dynamics during close approach to the Earth","authors":"K. Lobanova, A. V. Melnikov","doi":"10.31725/0367-7966-2024-233-39-50","DOIUrl":"https://doi.org/10.31725/0367-7966-2024-233-39-50","url":null,"abstract":"By means of numerical experiments, the influence of the value of the asteroid’s own rotational velocity, orientation of the axis of rotation, and figure parameters on the magnitude of perturbations in its rotational dynamics arising during close approach to the Earth is studied. Two cases are considered: 1) asteroid (99942) Apophis with a relatively slow rotation (period ≈ 30 h) and 2) asteroid 2012 TC4, which has a fast rotation (period ≈ 12 min). It was found that in the case of asteroids with slow rotation, perturbations can be large: in the case of Apophis, when approaching the Earth in 2029, changes in the rotational period ∆P may reach tens of hours, and deviations in the orientation of the axis of rotation ∆γ — tens of degrees. For fast-rotating asteroids, the perturbations are very small: in the case of asteroid 2012 TC4 at its approach to the Earth in 2017, |∆P | < 10−5 min, |∆γ| < 0.01◦. It is shown that for asteroids with slow rotation, the uncertainty in the determination of asteroid figure parameters (moments of inertia) can lead to noticeable inaccuracies in the estimation of perturbation magnitudes. The uncertainty in the knowledge of the figure parameters of a fast-rotating asteroid practically does not affect the estimation of perturbations in its rotational dynamics. In the case of Apophis, changes in the rotational velocity and orientation of the axis of rotation during the upcoming 2029 approach to the Earth may lead to a decrease in the value of the parameter A2, which characterizes the Yarkovsky effect, to −1.5 · 10−14 a.u./d2, or to an increase up to −3.5 · 10−14 a.u./d2. Perturbations in the rotational dynamics of asteroid 2012 TC4 during its approach to the Earth in 2017 did not affect the value of parameter A2.","PeriodicalId":503631,"journal":{"name":"Publications of the Pulkovo Observatory","volume":"33 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141410040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.31725/0367-7966-2024-233-29-33
V.L. Gorshkov, N.V. Scherbakova
GNSS data from the base maintained at the Pulkovo Observatory (VDB) and a similar base from the Nevada Geodetic Laboratory (NGL, USA) were used for research of the long-term dynamics of atmospheric precipitable water vapor over the territory of the East European Craton. The atmospheric precipitable water vapor is 0.03 mm/year.
{"title":"The dynamics of the atmospheric precipitable water vapor on GNSS observations over the territory of the East European Craton","authors":"V.L. Gorshkov, N.V. Scherbakova","doi":"10.31725/0367-7966-2024-233-29-33","DOIUrl":"https://doi.org/10.31725/0367-7966-2024-233-29-33","url":null,"abstract":"GNSS data from the base maintained at the Pulkovo Observatory (VDB) and a similar base from the Nevada Geodetic Laboratory (NGL, USA) were used for research of the long-term dynamics of atmospheric precipitable water vapor over the territory of the East European Craton. The atmospheric precipitable water vapor is 0.03 mm/year.","PeriodicalId":503631,"journal":{"name":"Publications of the Pulkovo Observatory","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141399567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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