Pub Date : 2020-03-01DOI: 10.31577/caosp.2020.50.2.635
I. Volkov
We present a new derivation of apsidal motion in the well known eclipsing eccentric binary α CrB.
我们提出了一个新的推导，在著名的偏心眼双星α CrB的附座运动。
{"title":"Apsidal motion in α CrB","authors":"I. Volkov","doi":"10.31577/caosp.2020.50.2.635","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.635","url":null,"abstract":"We present a new derivation of apsidal motion in the well known eclipsing eccentric binary α CrB.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83366128","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 : 2020-03-01DOI: 10.31577/caosp.2020.50.2.523
R. E. Wilson
The foundations of an analytic Accretion-Decretion (A-D) disk model, based on equipotential theory, for mass-transfer binaries are examined. Gravitation of stars 1 and 2 and the disk, as well as disk and star rotation, are included and relevant morphology is explored. Expected applications are to disks with morphologically significant mass and substantial optical thickness. Anticipated targets include classical novae, nova-like variables, and W Serpentis binaries, with the concept invoking knowledge about Be stars and the classically strange binary β Lyrae. The model’s ideas and resulting character differ from those usually applied to optically thick disks – for example there is no need to truncate the model arbitrarily at an outer or inner limit, because it closes naturally at both places. The disk is a volume emitter with attenuation of internally generated light. Computations intrinsically produce phenomena that are characteristic of circumstellar disks in binaries – in particular tidal and rotational gravity brightening and an outer effective gravity null point that do not occur in the common axisymmetric disk model. Impersonal analysis in terms of the model (Least Squares criterion) is applied to light curves of recurrent nova CI Aquilae.
{"title":"An analytic self-gravitating disk model: inferences and logical structure","authors":"R. E. Wilson","doi":"10.31577/caosp.2020.50.2.523","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.523","url":null,"abstract":"The foundations of an analytic Accretion-Decretion (A-D) disk model, based on equipotential theory, for mass-transfer binaries are examined. Gravitation of stars 1 and 2 and the disk, as well as disk and star rotation, are included and relevant morphology is explored. Expected applications are to disks with morphologically significant mass and substantial optical thickness. Anticipated targets include classical novae, nova-like variables, and W Serpentis binaries, with the concept invoking knowledge about Be stars and the classically strange binary β Lyrae. The model’s ideas and resulting character differ from those usually applied to optically thick disks – for example there is no need to truncate the model arbitrarily at an outer or inner limit, because it closes naturally at both places. The disk is a volume emitter with attenuation of internally generated light. Computations intrinsically produce phenomena that are characteristic of circumstellar disks in binaries – in particular tidal and rotational gravity brightening and an outer effective gravity null point that do not occur in the common axisymmetric disk model. Impersonal analysis in terms of the model (Least Squares criterion) is applied to light curves of recurrent nova CI Aquilae.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82701399","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 : 2020-03-01DOI: 10.31577/caosp.2020.50.2.539
A. Kochoska, K. Conroy, K. Hambleton, A. Prša
The parameter space of binary star light curve models is highly complex and degenerate, thus basic fitting approaches often fail to yield a good (and correct) estimate of the parameter values and their uncertainties. On the other hand, we have an increasingly large number of fitting and sampling algorithms available that can be relatively easily interfaced with open-source eclipsing binary packages, like PHOEBE 2. We showcase several fitting methods, including local and global minimizers, nested sampling and machine learning methods, and evaluate their performance on fitting a light curve model with PHOEBE 2.
{"title":"Beyond DC and MCMC: alternative algorithms and approaches to fitting light curves","authors":"A. Kochoska, K. Conroy, K. Hambleton, A. Prša","doi":"10.31577/caosp.2020.50.2.539","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.539","url":null,"abstract":"The parameter space of binary star light curve models is highly complex and degenerate, thus basic fitting approaches often fail to yield a good (and correct) estimate of the parameter values and their uncertainties. On the other hand, we have an increasingly large number of fitting and sampling algorithms available that can be relatively easily interfaced with open-source eclipsing binary packages, like PHOEBE 2. We showcase several fitting methods, including local and global minimizers, nested sampling and machine learning methods, and evaluate their performance on fitting a light curve model with PHOEBE 2.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79725634","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 : 2020-03-01DOI: 10.31577/caosp.2020.50.2.637
M. Wolf, H. Kučáková, P. Zasche, L. Šmelcer, K. Hornoch, K. Honkova, J. Juryšek, M. Mašek, M. Lehký
We present the new results of our long-term observational project to analyze the orbital period variations of low-mass eclipsing binaries. More then 200 new precise mid-eclipse times recorded with a CCD were obtained for three eclipsing binaries with short orbital periods: V380 Dra (P = 0. 49), BX Tri (0. 19), and V642 Vir (0. 52). Observed-minus-calculated diagrams of the stars were analyzed using all reliable timings, and new parameters of the light-time effect were obtained. We derived for the first time the short orbital periods of possible third bodies of 10–20 years for these objects. We calculated that the minimum masses of the third component are close to 0.2 M , which corresponds to the mass of M4 – M5 red dwarfs. The multiplicity of these systems also plays an important role in the precise determination of their physical parameters.
{"title":"Possible companions in low-mass eclipsing binaries: V380 Dra, BX Tri, and V642 Vir","authors":"M. Wolf, H. Kučáková, P. Zasche, L. Šmelcer, K. Hornoch, K. Honkova, J. Juryšek, M. Mašek, M. Lehký","doi":"10.31577/caosp.2020.50.2.637","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.637","url":null,"abstract":"We present the new results of our long-term observational project to analyze the orbital period variations of low-mass eclipsing binaries. More then 200 new precise mid-eclipse times recorded with a CCD were obtained for three eclipsing binaries with short orbital periods: V380 Dra (P = 0. 49), BX Tri (0. 19), and V642 Vir (0. 52). Observed-minus-calculated diagrams of the stars were analyzed using all reliable timings, and new parameters of the light-time effect were obtained. We derived for the first time the short orbital periods of possible third bodies of 10–20 years for these objects. We calculated that the minimum masses of the third component are close to 0.2 M , which corresponds to the mass of M4 – M5 red dwarfs. The multiplicity of these systems also plays an important role in the precise determination of their physical parameters.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90757718","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 : 2020-03-01DOI: 10.31577/caosp.2020.50.2.618
S. Parimucha, P. Dubovský, I. Kudzej, V. Breus, K. Petrík
Long term monitoring of intermediate polars is performed as part of the Inter-Longitude Astronomy campaign. High-quality and long time series observations allow us to investigate fine effects on complex light curves. In the case of MU Cam we have investigated the periodic modulation of the spin phases with the orbital phase. This dependency was already described by Kim et al. (2005). As an explanation they proposed inhomogeneous accretion flow from the secondary. However, based on our new data, we propose as a simple explanation the influence of orbital sidebands in the periodic signal produced by the intermediate polar. This explanation is supported by the fact that the changes in spin maxima phase are observed mainly when the sideband frequency is dominant in the periodogram.
{"title":"About the dependency of the spin maxima on orbital phase in the intermediate polar MU Cam","authors":"S. Parimucha, P. Dubovský, I. Kudzej, V. Breus, K. Petrík","doi":"10.31577/caosp.2020.50.2.618","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.618","url":null,"abstract":"Long term monitoring of intermediate polars is performed as part of the Inter-Longitude Astronomy campaign. High-quality and long time series observations allow us to investigate fine effects on complex light curves. In the case of MU Cam we have investigated the periodic modulation of the spin phases with the orbital phase. This dependency was already described by Kim et al. (2005). As an explanation they proposed inhomogeneous accretion flow from the secondary. However, based on our new data, we propose as a simple explanation the influence of orbital sidebands in the periodic signal produced by the intermediate polar. This explanation is supported by the fact that the changes in spin maxima phase are observed mainly when the sideband frequency is dominant in the periodogram.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79613921","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 : 2020-03-01DOI: 10.31577/caosp.2020.50.2.590
M. Reggiani, A. Rainot, H. Sana
The formation of massive stars remains one of the most intriguing questions in astrophysics today. Several formation theories, that could potentially be tested by the multiplicity properties of their outcome, have been proposed. There are, however, observational challenges preventing us from discriminating between the different formation scenarios: massive stars are rare and found at relative large distances from us, they form on short timescales and evolve in multiple stellar systems within the gas-rich environment from which they are born. Taking advantage of the extreme-adaptive optics capabilities of VLT/SPHERE, we observed more than 70 galactic O stars, about half in the Carina nebula and another half in the galactic field or clusters and associations, aiming at characterizing their multiplicity properties. SPHERE offers unprecedented imaging contrasts which allows us to detect even the faintest companions around massive stars. Here, we illustrate its capabilities by focussing on the high-order multiple system QZ Car.
{"title":"High-contrast imaging of massive stars: the example of QZ Car","authors":"M. Reggiani, A. Rainot, H. Sana","doi":"10.31577/caosp.2020.50.2.590","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.590","url":null,"abstract":"The formation of massive stars remains one of the most intriguing questions in astrophysics today. Several formation theories, that could potentially be tested by the multiplicity properties of their outcome, have been proposed. There are, however, observational challenges preventing us from discriminating between the different formation scenarios: massive stars are rare and found at relative large distances from us, they form on short timescales and evolve in multiple stellar systems within the gas-rich environment from which they are born. Taking advantage of the extreme-adaptive optics capabilities of VLT/SPHERE, we observed more than 70 galactic O stars, about half in the Carina nebula and another half in the galactic field or clusters and associations, aiming at characterizing their multiplicity properties. SPHERE offers unprecedented imaging contrasts which allows us to detect even the faintest companions around massive stars. Here, we illustrate its capabilities by focussing on the high-order multiple system QZ Car.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79680309","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 : 2020-03-01DOI: 10.31577/caosp.2020.50.2.560
V. Bahyl, M. Kodrík, E. Balážová, P. Tinh, O. Vacek, M. Vargovská
This paper presents the results of our mathematical experiment with light curves of variable stars with large apsidal motion. We have treated our photometric data for different positions of longitude of periastron with our reconstruction algorithms.
{"title":"Backprojection informatics of RU Monocerotis-type binary system light curves","authors":"V. Bahyl, M. Kodrík, E. Balážová, P. Tinh, O. Vacek, M. Vargovská","doi":"10.31577/caosp.2020.50.2.560","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.560","url":null,"abstract":"This paper presents the results of our mathematical experiment with light curves of variable stars with large apsidal motion. We have treated our photometric data for different positions of longitude of periastron with our reconstruction algorithms.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78576904","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 : 2020-03-01DOI: 10.31577/caosp.2020.50.2.504
E. Kıran, V. Bakış, H. Bakış
Eccentric eclipsing binaries (EEBs) are detached binary stars. Many EEBs show apsidal motion. EEB fundamental physical parameters allow us to test stellar evolution models and to estimate the internal stellar structure constants through apsidal motion analysis. We started a programme to study EEBs at the UBT60 telescope of Akdeniz University located at TÜBİTAK National Observatory. In this paper, we present spectroscopic orbital parameters of some selected EEBs.
{"title":"Spectroscopic observations of eccentric eclipsing binary systems","authors":"E. Kıran, V. Bakış, H. Bakış","doi":"10.31577/caosp.2020.50.2.504","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.504","url":null,"abstract":"Eccentric eclipsing binaries (EEBs) are detached binary stars. Many EEBs show apsidal motion. EEB fundamental physical parameters allow us to test stellar evolution models and to estimate the internal stellar structure constants through apsidal motion analysis. We started a programme to study EEBs at the UBT60 telescope of Akdeniz University located at TÜBİTAK National Observatory. In this paper, we present spectroscopic orbital parameters of some selected EEBs.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84240696","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 : 2020-03-01DOI: 10.31577/caosp.2020.50.2.594
H. V. Şenavcı, E. Bahar, I. Özavcı, T. Kılıçoğlu
We present the first Doppler Imaging (DI) study of the chromospherically active RS CVn binary FF Ursae Majoris. New mid-resolution (R ∼ 13500) time series spectral data were acquired using the echelle spectrograph attached to the 0.4-m Kreiken Telescope at the Ankara University Kreiken Observatory. We applied a spectral subtraction technique to the Hα line to reveal the phase behavior of the chromospheric activity of the system. The results derived from DI and spectral subtraction analyses show that both components exhibit photospheric and chromospheric activity. The time series spectral data also enable us to obtain the most recent radial velocity curve of the system and re-determine the physical parameters.
我们提出了第一个多普勒成像(DI)研究的显色球活性RS CVn双星大熊座FF。利用安卡拉大学Kreiken天文台的0.4 m Kreiken望远镜附带的阶梯式光谱仪获得了新的中分辨率(R ~ 13500)时间序列光谱数据。我们利用光谱减法技术对Hα线进行了分析，揭示了该体系色球活性的相行为。DI和光谱减法分析的结果表明，这两个组分都具有光球和色球活性。时间序列光谱数据也使我们能够获得系统最新的径向速度曲线，并重新确定物理参数。
{"title":"First Doppler imaging of the RS CVn binary FF UMa","authors":"H. V. Şenavcı, E. Bahar, I. Özavcı, T. Kılıçoğlu","doi":"10.31577/caosp.2020.50.2.594","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.594","url":null,"abstract":"We present the first Doppler Imaging (DI) study of the chromospherically active RS CVn binary FF Ursae Majoris. New mid-resolution (R ∼ 13500) time series spectral data were acquired using the echelle spectrograph attached to the 0.4-m Kreiken Telescope at the Ankara University Kreiken Observatory. We applied a spectral subtraction technique to the Hα line to reveal the phase behavior of the chromospheric activity of the system. The results derived from DI and spectral subtraction analyses show that both components exhibit photospheric and chromospheric activity. The time series spectral data also enable us to obtain the most recent radial velocity curve of the system and re-determine the physical parameters.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79617509","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 : 2020-03-01DOI: 10.31577/caosp.2020.50.2.607
P. Zasche
Bound pairs of eclipsing binaries have been studied for the last 10 years as parts of more complex multiple systems. We present new findings on these somewhat neglected objects, as well as motivation for their study. Detection methods, parameter distributions, resonances, and interesting sky distributions are discussed.
{"title":"Quadruple systems with two eclipsing binaries","authors":"P. Zasche","doi":"10.31577/caosp.2020.50.2.607","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.607","url":null,"abstract":"Bound pairs of eclipsing binaries have been studied for the last 10 years as parts of more complex multiple systems. We present new findings on these somewhat neglected objects, as well as motivation for their study. Detection methods, parameter distributions, resonances, and interesting sky distributions are discussed.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83428909","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}
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