Pub Date : 2020-11-17DOI: 10.31577/CAOSP.2021.51.1.45
J. Merc, Cs. Kalup, R. Rathour, J. S. Sánchez Arias, P. Beck
This paper summarizes the project work on asteroseismology at the ERASMUS+ GATE 2020 Summer school on space satellite data. The aim was to do a global asteroseismic analysis of KIC 5006817 and quantify its stellar properties using the high-quality, state of the art space missions data. We employed the aperture photometry to analyze the data from the Kepler space telescope and the Transiting Exoplanet Survey Satellite (TESS). Using the lightkurve Python package, we have derived the asteroseismic parameters and calculated the stellar parameters using the scaling relations. Our analysis of KIC 5006817 confirmed its classification as a heartbeat binary. The rich oscillation spectrum facilitate estimating power excess ($nu_{rm max}$) at 145.50$pm$0.50 $mu$Hz and large frequency separation ($Deltanu$) to be 11.63$pm$0.10 $mu$Hz. Our results showed that the primary component is a low-luminosity, red-giant branch star with a mass, radius, surface gravity, and luminosity of 1.53$pm$0.07 M$_odot$, 5.91$pm$0.12 R$_odot$, 3.08$pm$0.01 dex, and 19.66$pm$0.73 L$_odot$, respectively. The orbital period of the system is 94.83$pm$0.05 d.
{"title":"Asteroseismology of the heartbeat star KIC 5006817","authors":"J. Merc, Cs. Kalup, R. Rathour, J. S. Sánchez Arias, P. Beck","doi":"10.31577/CAOSP.2021.51.1.45","DOIUrl":"https://doi.org/10.31577/CAOSP.2021.51.1.45","url":null,"abstract":"This paper summarizes the project work on asteroseismology at the ERASMUS+ GATE 2020 Summer school on space satellite data. The aim was to do a global asteroseismic analysis of KIC 5006817 and quantify its stellar properties using the high-quality, state of the art space missions data. We employed the aperture photometry to analyze the data from the Kepler space telescope and the Transiting Exoplanet Survey Satellite (TESS). Using the lightkurve Python package, we have derived the asteroseismic parameters and calculated the stellar parameters using the scaling relations. Our analysis of KIC 5006817 confirmed its classification as a heartbeat binary. The rich oscillation spectrum facilitate estimating power excess ($nu_{rm max}$) at 145.50$pm$0.50 $mu$Hz and large frequency separation ($Deltanu$) to be 11.63$pm$0.10 $mu$Hz. Our results showed that the primary component is a low-luminosity, red-giant branch star with a mass, radius, surface gravity, and luminosity of 1.53$pm$0.07 M$_odot$, 5.91$pm$0.12 R$_odot$, 3.08$pm$0.01 dex, and 19.66$pm$0.73 L$_odot$, respectively. The orbital period of the system is 94.83$pm$0.05 d.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":"44 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78271599","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}
Pub Date : 2020-11-01DOI: 10.31577/caosp.2020.50.4.774
A. Papageorgiou, P. Christopoulou, M. Catelán, A. Drake, S. Djorgovski
With the recent availability of large-scale multi-epoch photometric datasets, we were able to study EBs en masse. Large samples are useful to determine not only statistical properties but for finding strange and curious systems that no one had ever studied before, binaries with peculiarities that may reveal physical significance. We present an updated and more detailed catalog of 4680 Northern EAs in the Catalina Sky Survey (CSS). This work includes, new systems, revised period determination and ephemerides, system morphology classification based on machine learning techniques, computation of principal physical parameters with the EBAI (Eclipsing Binary via Artificial Intelligence) and detection of eclipse timing variations. We identify several groups of interesting systems including those with low mass K and M dwarfs, systems with longterm modulation of the maximum brightness, systems with longterm period modulation, potential triple systems and systems with magnetic activity.
{"title":"What we can learn from eclipsing binaries in large surveys: The case of EA Catalina systems","authors":"A. Papageorgiou, P. Christopoulou, M. Catelán, A. Drake, S. Djorgovski","doi":"10.31577/caosp.2020.50.4.774","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.4.774","url":null,"abstract":"With the recent availability of large-scale multi-epoch photometric datasets, we were able to study EBs en masse. Large samples are useful to determine not only statistical properties but for finding strange and curious systems that no one had ever studied before, binaries with peculiarities that may reveal physical significance. We present an updated and more detailed catalog of 4680 Northern EAs in the Catalina Sky Survey (CSS). This work includes, new systems, revised period determination and ephemerides, system morphology classification based on machine learning techniques, computation of principal physical parameters with the EBAI (Eclipsing Binary via Artificial Intelligence) and detection of eclipse timing variations. We identify several groups of interesting systems including those with low mass K and M dwarfs, systems with longterm modulation of the maximum brightness, systems with longterm period modulation, potential triple systems and systems with magnetic activity.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48505073","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}
Pub Date : 2020-11-01DOI: 10.31577/caosp.2020.50.4.772
K. Zervas, E. Christopoulou, A. Papageorgiou
. We present an extensive analysis of O-C diagrams constructed by previously published times of minima and updated by photometric observations carried out at Mythodea Observatory (Astrophysics Laboratory, Department of Physics, University of Patras). A two-companion model is attributed to the over-contact (W UMa type) binary system TZ Boo according to a Light-Time Effect (LITE), while in the case of the post-common envelope binary NSVS 14256825 a Jovian type circumbinary companion is the most plausible explanation of the apparent period variation.
{"title":"Substellar and stellar companions in eclipsing binaries","authors":"K. Zervas, E. Christopoulou, A. Papageorgiou","doi":"10.31577/caosp.2020.50.4.772","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.4.772","url":null,"abstract":". We present an extensive analysis of O-C diagrams constructed by previously published times of minima and updated by photometric observations carried out at Mythodea Observatory (Astrophysics Laboratory, Department of Physics, University of Patras). A two-companion model is attributed to the over-contact (W UMa type) binary system TZ Boo according to a Light-Time Effect (LITE), while in the case of the post-common envelope binary NSVS 14256825 a Jovian type circumbinary companion is the most plausible explanation of the apparent period variation.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48397164","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}
Pub Date : 2020-11-01DOI: 10.31577/caosp.2020.50.4.748
M. Vavrukh, D. Dzikovskyi
. The fundamental stages of development of the polytropic theory of stars with axial rotation are considered as a generalization of the Lane-Emden theory. The solution of the differential equilibrium equation for the polytropic star model with index n = 1 and axial rotation with the angular velocity ω is presented in the form of infinite series of the Legendre polynomials and the spherical Bessel functions. Two variants of the approximate solution in the form of the finite number of terms are proposed. Integration constants were found in a self-consistent way using the integral form of the equilibrium equation and the iteration numerical method. Dependence of the geometrical and physical characteristics of the model on the dimensionless angular velocity Ω = ω (2 πGρ c ) − 1 / 2 (where ρ c is the density in the centre) is analyzed. A comparison with the results of other authors is performed. The obtained critical value of the angular velocity Ω max , when an instability occurs is smaller than in other works (Chandrasekhar, 1933; James, 1964, and et al.). The inverse problem is also considered – a determination of the polytropic model parameters for individual stars based on the solution of the equilibrium equation according to the values of their masses and radii, which are known from observations. In particular, the model parameters for the star α Eri, as well as a similar “class” of the star models of types O5 ÷ G0, were determined. The solution of the equilibrium equation for the polytrope n = 1+ δ (where δ is a small value) is obtained using the method of perturbation theory.
.具有轴向旋转的恒星的多变理论发展的基本阶段被认为是Lane-Emden理论的推广。指数为n=1、轴旋转角速度为ω的多变恒星模型的微分平衡方程的解以勒让德多项式和球面贝塞尔函数的有限级数的形式给出。提出了有限项形式的近似解的两种变体。利用平衡方程的积分形式和迭代数值方法，以自洽的方式求出了积分常数。模型的几何和物理特性对无量纲角速度的依赖性Ω = ω（2πGρc）−1/2（其中ρc是中心的密度）进行了分析。与其他作者的结果进行了比较。获得的角速度临界值Ω 当不稳定发生时，max比其他工作中的要小（Chandrasekhar，1933；James，1964，and et al.）。还考虑了反问题——根据观测中已知的恒星质量和半径的值，根据平衡方程的解，确定单个恒星的多变模型参数。特别是，确定了αEri恒星的模型参数，以及O5÷G0类型的类似“类别”恒星模型。用微扰理论的方法得到了n=1+δ（其中δ是一个小值）多索的平衡方程的解。
{"title":"Exact solution for the rotating polytropes with index unity, its approximations and some applications","authors":"M. Vavrukh, D. Dzikovskyi","doi":"10.31577/caosp.2020.50.4.748","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.4.748","url":null,"abstract":". The fundamental stages of development of the polytropic theory of stars with axial rotation are considered as a generalization of the Lane-Emden theory. The solution of the differential equilibrium equation for the polytropic star model with index n = 1 and axial rotation with the angular velocity ω is presented in the form of infinite series of the Legendre polynomials and the spherical Bessel functions. Two variants of the approximate solution in the form of the finite number of terms are proposed. Integration constants were found in a self-consistent way using the integral form of the equilibrium equation and the iteration numerical method. Dependence of the geometrical and physical characteristics of the model on the dimensionless angular velocity Ω = ω (2 πGρ c ) − 1 / 2 (where ρ c is the density in the centre) is analyzed. A comparison with the results of other authors is performed. The obtained critical value of the angular velocity Ω max , when an instability occurs is smaller than in other works (Chandrasekhar, 1933; James, 1964, and et al.). The inverse problem is also considered – a determination of the polytropic model parameters for individual stars based on the solution of the equilibrium equation according to the values of their masses and radii, which are known from observations. In particular, the model parameters for the star α Eri, as well as a similar “class” of the star models of types O5 ÷ G0, were determined. The solution of the equilibrium equation for the polytrope n = 1+ δ (where δ is a small value) is obtained using the method of perturbation theory.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44347310","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}
Pub Date : 2020-08-20DOI: 10.31577/caosp.2020.50.4.717
M. Skulskyy
This article proposes a picture of magnetized accretion structures formed during the mass transfer in the Beta Lyrae system. It is shown that the structure of the gaseous flows between the donor and the gainer is due to the spatial configuration of the donor magnetic field. Its dipole axis is deviated substantially from the line joining the centers of the components and is inclined to the orbital plane of the binary system; the center of the magnetic dipole is displaced from the donor center toward the gainer. The surface around the donor magnetic pole, which is close to the gainer, is a region of an additional matter loss from the donor surface. The effective collision of the magnetized plasma with the accretion disk is enhanced by the fast counter-rotation of this disk, especially in the secondary quadrature phases, in which the high-temperature medium and the system of formed accretion flows are observed. This concept is demonstrated, primarily, in the obvious correlations between the phase variability of the donor magnetic field and the corresponding variability of the dynamic and energy characteristics of the various complex lines. This refers to the behavior of the radial velocity curves of the emission-absorption lines formed in the gaseous structures of type H$alpha$, HeI $lambda$ 7065, or the variability of their equivalent width and intensity, and the variability of conventional absorption lines of the donor atmosphere. This is true for the phase variability of the absolute flux in the H$alpha$ emission line and the fast varying of the continuum in the H$alpha$ region as certain parameters, which reflect the phase variability of the donor magnetic field. This approach made it possible to determine the phase boundaries of the location of the magnetic polar region on the donor surface above which the matter outflows are formed.
本文提出了一幅在天琴座β星系的质量传递过程中形成的磁化吸积结构的图像。结果表明，供体磁场的空间构型决定了供体与增益体之间气体流动的结构。它的偶极轴与元件中心连接线有很大的偏离，并向双星系统的轨道平面倾斜;磁偶极子的中心由施主中心向增益中心偏移。供体磁极周围靠近增益器的表面是供体表面附加物质损失的区域。吸积盘的快速反旋转增强了磁化等离子体与吸积盘的有效碰撞，特别是在二次正交阶段，高温介质和形成的吸积流系统被观察到。这一概念主要体现在供体磁场的相位变异性与各种复线的动态和能量特性的相应变异性之间的明显相关性中。这是指在H $alpha$, HeI $lambda$ 7065型气体结构中形成的发射-吸收谱线的径向速度曲线的行为，或其等效宽度和强度的可变性，以及供体大气常规吸收谱线的可变性。H $alpha$发射线上绝对通量的相位变化和H $alpha$区域连续体的快速变化作为一定的参数，反映了供体磁场的相位变化。这种方法使得确定物质流出形成的供体表面上磁极区位置的相边界成为可能。
{"title":"Formation of magnetized spatial structures in the Beta Lyrae system. II. Reflection of magnetically controlled structures in the visible spectrum","authors":"M. Skulskyy","doi":"10.31577/caosp.2020.50.4.717","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.4.717","url":null,"abstract":"This article proposes a picture of magnetized accretion structures formed during the mass transfer in the Beta Lyrae system. It is shown that the structure of the gaseous flows between the donor and the gainer is due to the spatial configuration of the donor magnetic field. Its dipole axis is deviated substantially from the line joining the centers of the components and is inclined to the orbital plane of the binary system; the center of the magnetic dipole is displaced from the donor center toward the gainer. The surface around the donor magnetic pole, which is close to the gainer, is a region of an additional matter loss from the donor surface. The effective collision of the magnetized plasma with the accretion disk is enhanced by the fast counter-rotation of this disk, especially in the secondary quadrature phases, in which the high-temperature medium and the system of formed accretion flows are observed. This concept is demonstrated, primarily, in the obvious correlations between the phase variability of the donor magnetic field and the corresponding variability of the dynamic and energy characteristics of the various complex lines. This refers to the behavior of the radial velocity curves of the emission-absorption lines formed in the gaseous structures of type H$alpha$, HeI $lambda$ 7065, or the variability of their equivalent width and intensity, and the variability of conventional absorption lines of the donor atmosphere. This is true for the phase variability of the absolute flux in the H$alpha$ emission line and the fast varying of the continuum in the H$alpha$ region as certain parameters, which reflect the phase variability of the donor magnetic field. This approach made it possible to determine the phase boundaries of the location of the magnetic polar region on the donor surface above which the matter outflows are formed.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41951487","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}
Pub Date : 2020-07-01DOI: 10.31577/caosp.2020.50.3.647
A. Skopal, R. Komžík
{"title":"Editorial","authors":"A. Skopal, R. Komžík","doi":"10.31577/caosp.2020.50.3.647","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.3.647","url":null,"abstract":"","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42459173","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}
Pub Date : 2020-07-01DOI: 10.31577/caosp.2020.50.3.704
R. Hudec, E. Splittgerber
The scanned astronomical archival plates offer the possibility of alternative analyses on these data. Apart from a complete evaluation by sophisticated computer programs, the recent efforts offer an alternative fast method of eye estimation method using scanned plates exhibited on computer screens. This alternative method has been investigated by analyzing the light curve of XX Cep on several hundred scanned sky patrol plates from the Sonneberg Observatory plate archive.
{"title":"Note on magnitude estimation on digitized astronomical photographic plates","authors":"R. Hudec, E. Splittgerber","doi":"10.31577/caosp.2020.50.3.704","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.3.704","url":null,"abstract":"The scanned astronomical archival plates offer the possibility of alternative analyses on these data. Apart from a complete evaluation by sophisticated computer programs, the recent efforts offer an alternative fast method of eye estimation method using scanned plates exhibited on computer screens. This alternative method has been investigated by analyzing the light curve of XX Cep on several hundred scanned sky patrol plates from the Sonneberg Observatory plate archive.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":"18 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78437485","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}
Pub Date : 2020-05-21DOI: 10.31577/caosp.2020.50.3.681
M. Skulskyy
The discovery of the donor magnetic field has repeatedly posed the task of a thorough study of the phenomenon, which is based on the concept of the influence of the magnetic field on the processes of the formation of gaseous structures and mass transfer in the Beta Lyrae system. This article provides an overview, analysis, and synthesis of the results of a variety of long-term observations as a necessary basis for further clarification of issues aimed primarily at the study of magnetized gaseous structures. As a part of such a study, it was found that the structure of the gaseous flows between the donor and the gainer varies in some way depending on the phases of the orbital period; and, accordingly, that the donor magnetic field influences the formation of these moving magnetized structures. The analysis of the masses of both components for use in further scientific works suggests that the following values are optimal: 2.9 M_sun for the donor and 13 M_sun for the gainer. The study of satellite lines as a certain phenomenon leads to the fact that the accretion disk surrounding the gainer consists of two parts: the external satellite disk and the internal massive opaque disk. From the analysis of all observations and studies of the magnetic field, observations on the 6-m telescope can be considered the most reliable. They have formed the spatial configuration of the donor magnetic field, which is important for studying and understanding the features of the mass transfer in this interacting system. Further evidence regarding the picture of the magnetized accretion structures as the special phenomenon will be presented in the following articles.
{"title":"Formation of magnetized spatial structures in the Beta Lyrae system. I. Observation as a research background of this phenomenon","authors":"M. Skulskyy","doi":"10.31577/caosp.2020.50.3.681","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.3.681","url":null,"abstract":"The discovery of the donor magnetic field has repeatedly posed the task of a thorough study of the phenomenon, which is based on the concept of the influence of the magnetic field on the processes of the formation of gaseous structures and mass transfer in the Beta Lyrae system. This article provides an overview, analysis, and synthesis of the results of a variety of long-term observations as a necessary basis for further clarification of issues aimed primarily at the study of magnetized gaseous structures. As a part of such a study, it was found that the structure of the gaseous flows between the donor and the gainer varies in some way depending on the phases of the orbital period; and, accordingly, that the donor magnetic field influences the formation of these moving magnetized structures. The analysis of the masses of both components for use in further scientific works suggests that the following values are optimal: 2.9 M_sun for the donor and 13 M_sun for the gainer. The study of satellite lines as a certain phenomenon leads to the fact that the accretion disk surrounding the gainer consists of two parts: the external satellite disk and the internal massive opaque disk. From the analysis of all observations and studies of the magnetic field, observations on the 6-m telescope can be considered the most reliable. They have formed the spatial configuration of the donor magnetic field, which is important for studying and understanding the features of the mass transfer in this interacting system. Further evidence regarding the picture of the magnetized accretion structures as the special phenomenon will be presented in the following articles.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43089791","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}
Pub Date : 2020-05-15DOI: 10.31577/CAOSP.2020.50.3.649
T. Pribulla, L. Hambalek, E. Guenther, R. Komžík, E. Kundra, J. Nedoroščík, V. Perdelwitz, M. Vaňko
BD And is a fairly bright (V = 10.8), active and close (P = 0.9258 days) eclipsing binary. The cyclic variability of the apparent orbital period as well as third light in the light curves indicate the presence of an additional late-type component. The principal aim is the spectroscopic testing of the third-body hypothesis and determination of absolute stellar parameters for both components of the eclipsing binary. First medium and high-resolution spectroscopy of the system was obtained. The broadening-function technique appropriate for heavily-broadened spectra of close binaries was used. The radial velocities were determined fitting the Gaussian functions and rotational profiles to the broadening functions. A limited amount of photometric data has also been obtained. Although the photometric observations were focused on the obtaining the timing information, a cursory light-curve analysis was also performed. Extracted broadening functions clearly show the presence of a third, slowly-rotating component. Its radial velocity is within error of the systemic velocity of the eclipsing pair, strongly supporting the physical bond. The observed systemic radial-velocity and third-component changes do not support the 9 year orbit found from the timing variability. Masses of the components of the eclipsing pair are determined with about 0.5% precision. Further characterization of the system would require long-term photometric and spectroscopic monitoring.
{"title":"Close eclipsing binary BD And: a triple system","authors":"T. Pribulla, L. Hambalek, E. Guenther, R. Komžík, E. Kundra, J. Nedoroščík, V. Perdelwitz, M. Vaňko","doi":"10.31577/CAOSP.2020.50.3.649","DOIUrl":"https://doi.org/10.31577/CAOSP.2020.50.3.649","url":null,"abstract":"BD And is a fairly bright (V = 10.8), active and close (P = 0.9258 days) eclipsing binary. The cyclic variability of the apparent orbital period as well as third light in the light curves indicate the presence of an additional late-type component. The principal aim is the spectroscopic testing of the third-body hypothesis and determination of absolute stellar parameters for both components of the eclipsing binary. First medium and high-resolution spectroscopy of the system was obtained. The broadening-function technique appropriate for heavily-broadened spectra of close binaries was used. The radial velocities were determined fitting the Gaussian functions and rotational profiles to the broadening functions. A limited amount of photometric data has also been obtained. Although the photometric observations were focused on the obtaining the timing information, a cursory light-curve analysis was also performed. Extracted broadening functions clearly show the presence of a third, slowly-rotating component. Its radial velocity is within error of the systemic velocity of the eclipsing pair, strongly supporting the physical bond. The observed systemic radial-velocity and third-component changes do not support the 9 year orbit found from the timing variability. Masses of the components of the eclipsing pair are determined with about 0.5% precision. Further characterization of the system would require long-term photometric and spectroscopic monitoring.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47987388","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}
Pub Date : 2020-04-22DOI: 10.31577/CAOSP.2020.50.3.672
V. Andreoli, U. Munari
LAMOST J202629.80+423652.0 has been recently classified as a new symbiotic star containing a long-period Mira, surrounded by dust (D-type) and displaying in the optical spectra high ionization emission lines, including the Raman-scattered OVI at 6825 Ang. We have observed LAMOST J202629.80+423652.0 photometrically in the BVRI bands and spectroscopically over the 3500-8000 Ang range. We have found it to be a normal G8IV sub-giant star, deprived of any emission line in its spectrum, and reddened by E(B-V)=0.35 mag. Combining our photometry with data from all-sky patrol surveys, we find LAMOST J202629.80+423652.0 to be non variable, so not pulsating as a Mira. We have compiled from existing sources its spectral energy distribution, extending well into the mid-Infrared, and found it completely dominated by the G8IV photospheric stellar emission, without any sign of circumstellar dust. We therefore conclude that LAMOST J202629.80+423652.0 is not a symbiotic star, nor it is pulsating or been enshrouded in dust.
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