Pub Date : 2020-04-06DOI: 10.31577/caosp.2020.50.2.442
M. Skarka, Z. Prudil, J. Liška
There is a significant lack of binary stars with RR Lyrae components. In this brief contribution, we introduce 20 new candidates in the Galactic bulge identified on the basis of the Light-Travel-Time Effect with expected orbital periods between 3 and 15 years.
{"title":"Binary stars with RR Lyrae components -- new candidates in the Galactic bulge","authors":"M. Skarka, Z. Prudil, J. Liška","doi":"10.31577/caosp.2020.50.2.442","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.442","url":null,"abstract":"There is a significant lack of binary stars with RR Lyrae components. In this brief contribution, we introduce 20 new candidates in the Galactic bulge identified on the basis of the Light-Travel-Time Effect with expected orbital periods between 3 and 15 years.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47917876","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 : 2020-04-06DOI: 10.31577/caosp.2020.50.2.486
L. Celedón, R. Mennickent, S. Zharikov, J. Garces, M. Cabezas, G. Aguayo
AU Monocerotis is a well studied interacting binary star and a member of a group called Double Periodic Variables, whose principal characteristic is the existence of a long photometric cycle lasting on average about 33 times the orbital period. We made use of spectra covering from 2008 to 2015 to construct Hα Doppler maps. We found higher activity in the accretion disk during the low state of the system, similar to that found in HD 170582.
AU Monocerotis是一颗被充分研究的相互作用双星，是双周期变星组的成员，其主要特征是存在一个平均持续约33倍轨道周期的长光度周期。利用2008 - 2015年的光谱覆盖，构建了h - α多普勒图。我们发现，在系统的低状态下，吸积盘的活动更活跃，这与HD 170582的情况类似。
{"title":"On the variability of the accretion disk of AU Monocerotis","authors":"L. Celedón, R. Mennickent, S. Zharikov, J. Garces, M. Cabezas, G. Aguayo","doi":"10.31577/caosp.2020.50.2.486","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.486","url":null,"abstract":"AU Monocerotis is a well studied interacting binary star and a member of a group called Double Periodic Variables, whose principal characteristic is the existence of a long photometric cycle lasting on average about 33 times the orbital period. We made use of spectra covering from 2008 to 2015 to construct Hα Doppler maps. We found higher activity in the accretion disk during the low state of the system, similar to that found in HD 170582.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91342308","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 : 2020-04-06DOI: 10.31577/caosp.2020.50.2.481
E. Bahar, I. Özavcı, H. V. Şenavcı
High precision and continuous light curves obtained from the Kepler Space Telescope provide significant information about the behavior of cool starspots. In this study, we obtain surface maps of the eclipsing binary KIC 9821078 with the help of the light curve inversion method to reveal longitudinal spot migration from Kepler long-cadence (LC) light curves. We also present an upto-date solution from light and radial velocity curves. The inversion results find at least two dominant spot regions that migrate from lower to higher longitudes as a consequence of solar-like differential rotation.
{"title":"Spot migration on the eclipsing binary KIC 9821078","authors":"E. Bahar, I. Özavcı, H. V. Şenavcı","doi":"10.31577/caosp.2020.50.2.481","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.481","url":null,"abstract":"High precision and continuous light curves obtained from the Kepler Space Telescope provide significant information about the behavior of cool starspots. In this study, we obtain surface maps of the eclipsing binary KIC 9821078 with the help of the light curve inversion method to reveal longitudinal spot migration from Kepler long-cadence (LC) light curves. We also present an upto-date solution from light and radial velocity curves. The inversion results find at least two dominant spot regions that migrate from lower to higher longitudes as a consequence of solar-like differential rotation.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77312536","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 : 2020-04-06DOI: 10.31577/caosp.2020.50.2.472
M. Renzo, E. Zapartas
Massive stars are born predominantly as members of binary (or higher multiplicity) systems, and the presence of a companion can significantly alter their life and final fate. Therefore, any observed sample of massive stars or associated transients is likely to be significantly influenced by the effects of binarity. Here, we focus on the relationship between massive binary evolution and core-collapse supernova events. In the vast majority of the cases, the first core-collapse event happening in a binary system unbinds the two stars. Studying the population of companion stars, either at the supernova site, or as "widowed" stars long after the explosion, can be used to constrain the previous orbital evolution of the binary progenitor, and explosion physics of their former companion. Specifically, the population of "widowed" stars might provide statistical constraints on the typical amplitude of black hole natal kicks without seeing neither the black holes nor the transient possibly associated with their formation. Binarity also has a large impact on the predicted population of supernova sub-types, including hydrogen-rich type II supernovae, with a significant fraction of hydrogen-rich stars at explosions being either merger products or accretors.
{"title":"The explosive life of massive binaries","authors":"M. Renzo, E. Zapartas","doi":"10.31577/caosp.2020.50.2.472","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.472","url":null,"abstract":"Massive stars are born predominantly as members of binary (or higher multiplicity) systems, and the presence of a companion can significantly alter their life and final fate. Therefore, any observed sample of massive stars or associated transients is likely to be significantly influenced by the effects of binarity. Here, we focus on the relationship between massive binary evolution and core-collapse supernova events. In the vast majority of the cases, the first core-collapse event happening in a binary system unbinds the two stars. Studying the population of companion stars, either at the supernova site, or as \"widowed\" stars long after the explosion, can be used to constrain the previous orbital evolution of the binary progenitor, and explosion physics of their former companion. Specifically, the population of \"widowed\" stars might provide statistical constraints on the typical amplitude of black hole natal kicks without seeing neither the black holes nor the transient possibly associated with their formation. Binarity also has a large impact on the predicted population of supernova sub-types, including hydrogen-rich type II supernovae, with a significant fraction of hydrogen-rich stars at explosions being either merger products or accretors.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42126999","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 : 2020-04-06DOI: 10.31577/caosp.2020.50.2.490
B. Debski
The longitudinal spot migration can be traced with the observation of the O’Connell effect and maxima separation variations. Judging by the correlations between the light curve parameters, the migration processes are confined to the polar regions of the more massive star in a contact binary.
{"title":"Starspot trek: The motion picture","authors":"B. Debski","doi":"10.31577/caosp.2020.50.2.490","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.490","url":null,"abstract":"The longitudinal spot migration can be traced with the observation of the O’Connell effect and maxima separation variations. Judging by the correlations between the light curve parameters, the migration processes are confined to the polar regions of the more massive star in a contact binary.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83214827","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 : 2020-04-06DOI: 10.31577/caosp.2020.50.2.436
J. Rukmini, D. S. Priya, M. R. Prasad, P. R. Raja
Contact binaries form an interesting class of binaries which not only show mutual interactions through gravitationally bound periodic close orbits, but also dynamical interactions through mass transfer, angular momentum loss and modulation of their orbits due to the presence of tertiary components and magnetic activity. They are important as distance indicators and laboratories to study stellar evolutionary models. The current work highlights our photometric study of 61 totally eclipsing contact binaries from the ASAS, OGLE, HATNet, AST3 and TESS databases. Physical parameters are derived using PHOEBE. The selected binaries fall in a range of short periods (0.34-0.97 d), low mass ratios (0.076-0.504), F5-M0 spectral types, and a wide range of fillout factors (3-85%). Based on obtained fillout factors, 5 were classified as shallow/marginal contact, 41 as over-contact and 15 as deep-contact binaries. The absolute parameters are compared with those of well-studied binaries. Possible evolutionary states are discussed.
{"title":"Photometric study of 61 totally eclipsing contact binaries from the ASAS, OGLE, HATNet, AST3 and TESS databases.","authors":"J. Rukmini, D. S. Priya, M. R. Prasad, P. R. Raja","doi":"10.31577/caosp.2020.50.2.436","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.436","url":null,"abstract":"Contact binaries form an interesting class of binaries which not only show mutual interactions through gravitationally bound periodic close orbits, but also dynamical interactions through mass transfer, angular momentum loss and modulation of their orbits due to the presence of tertiary components and magnetic activity. They are important as distance indicators and laboratories to study stellar evolutionary models. The current work highlights our photometric study of 61 totally eclipsing contact binaries from the ASAS, OGLE, HATNet, AST3 and TESS databases. Physical parameters are derived using PHOEBE. The selected binaries fall in a range of short periods (0.34-0.97 d), low mass ratios (0.076-0.504), F5-M0 spectral types, and a wide range of fillout factors (3-85%). Based on obtained fillout factors, 5 were classified as shallow/marginal contact, 41 as over-contact and 15 as deep-contact binaries. The absolute parameters are compared with those of well-studied binaries. Possible evolutionary states are discussed.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87177940","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 : 2020-04-06DOI: 10.31577/caosp.2020.50.2.461
G. Loukaidou, K. Gazeas
The evolution of eclipsing binaries leads towards angular momentum and mass loss from the systems, due to stellar wind and magnetic braking. Observational investigations of low-temperature and low-mass contact binaries (or LMCBs) in the solar neighborhood provide the means for studying a large sample of such systems. The observed orbital period cut-off limit of 0.22 days is believed to be a result of evolutionary mechanisms, and such systems act as probes in investigating the very evolved stages of systems before their final coalescence. The main goal of this study is the determination of the stellar evolution tracks of these type of LMCBs, which might be correlated to the formation of blue stragglers and rapidly rotating stars.
{"title":"Evolution of low mass contact binaries close to the orbital period cut-off","authors":"G. Loukaidou, K. Gazeas","doi":"10.31577/caosp.2020.50.2.461","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.461","url":null,"abstract":"The evolution of eclipsing binaries leads towards angular momentum and mass loss from the systems, due to stellar wind and magnetic braking. Observational investigations of low-temperature and low-mass contact binaries (or LMCBs) in the solar neighborhood provide the means for studying a large sample of such systems. The observed orbital period cut-off limit of 0.22 days is believed to be a result of evolutionary mechanisms, and such systems act as probes in investigating the very evolved stages of systems before their final coalescence. The main goal of this study is the determination of the stellar evolution tracks of these type of LMCBs, which might be correlated to the formation of blue stragglers and rapidly rotating stars.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73670197","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 : 2020-04-06DOI: 10.31577/caosp.2020.50.2.446
Z. Hartman, S. Lépine
The SUPERWIDE catalog is an all-sky catalog of ∼90,000 wide binaries with projected orbital separations ∼100 to 100,000 AU, mostly located within 500 pc of the Sun. These consist of common proper motion (CPM) pairs of high proper motion stars (> 40 mas/yr). A Bayesian analysis using positions, proper motions and distances from Gaia Data Release 2 (DR2) shows these pairs to have probabilities > 99% of being gravitationally bound systems. Here, we examine K+K wide binaries, which allow for easy identification of unresolved higher-order systems because the K dwarf main sequence is narrow and unresolved subsystems are easily identified as over-luminous. We found 980 systems where at least one of the wide components is over-luminous, which means they are higher-order systems (triples and quadruples). Although metallicity efffects generally complicate the identification of over-luminous stars, we show that this can be easily accounted for in wide binaries, making the identification of unresolved subsystems relatively straightforward. Taking these effects into account, we calculate the higher-order multiplicity fraction to be 39.6%.
{"title":"K dwarf triples and quadruples in the SUPERWIDE catalog of 90,000 nearby wide binaries","authors":"Z. Hartman, S. Lépine","doi":"10.31577/caosp.2020.50.2.446","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.446","url":null,"abstract":"The SUPERWIDE catalog is an all-sky catalog of ∼90,000 wide binaries with projected orbital separations ∼100 to 100,000 AU, mostly located within 500 pc of the Sun. These consist of common proper motion (CPM) pairs of high proper motion stars (> 40 mas/yr). A Bayesian analysis using positions, proper motions and distances from Gaia Data Release 2 (DR2) shows these pairs to have probabilities > 99% of being gravitationally bound systems. Here, we examine K+K wide binaries, which allow for easy identification of unresolved higher-order systems because the K dwarf main sequence is narrow and unresolved subsystems are easily identified as over-luminous. We found 980 systems where at least one of the wide components is over-luminous, which means they are higher-order systems (triples and quadruples). Although metallicity efffects generally complicate the identification of over-luminous stars, we show that this can be easily accounted for in wide binaries, making the identification of unresolved subsystems relatively straightforward. Taking these effects into account, we calculate the higher-order multiplicity fraction to be 39.6%.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81022969","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 : 2020-04-06DOI: 10.31577/caosp.2020.50.2.448
A. Tokovinin
Many (but not all) close binaries are inner pairs in triple and higherorder hierarchical systems. The statistical relation between close binaries and hierarchical systems is well established. Although close binaries can form by a combination of Kozai-Lidov cycles with tides, the study of Moe & Kratter (2018) indicated that only a fraction of them could be produced by this mechanism and that many close binaries form even before stars contract onto the main sequence. The predicted statistical signatures of tidal formation, such as accumulation of periods just below the tidal cutoff, are not observed. Instead, the main channel of close-binary formation is likely accretion-driven migration. The relation between close binaries and triple stars is not casual, it derives from the common factor which is the accretion strength. High accretion creates massive stars that have a large fraction of close binaries and, at the same time, a large fraction of hierarchical systems.
{"title":"Close binaries in hierarchical stellar systems","authors":"A. Tokovinin","doi":"10.31577/caosp.2020.50.2.448","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.448","url":null,"abstract":"Many (but not all) close binaries are inner pairs in triple and higherorder hierarchical systems. The statistical relation between close binaries and hierarchical systems is well established. Although close binaries can form by a combination of Kozai-Lidov cycles with tides, the study of Moe & Kratter (2018) indicated that only a fraction of them could be produced by this mechanism and that many close binaries form even before stars contract onto the main sequence. The predicted statistical signatures of tidal formation, such as accumulation of periods just below the tidal cutoff, are not observed. Instead, the main channel of close-binary formation is likely accretion-driven migration. The relation between close binaries and triple stars is not casual, it derives from the common factor which is the accretion strength. High accretion creates massive stars that have a large fraction of close binaries and, at the same time, a large fraction of hierarchical systems.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88756542","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 : 2020-04-01DOI: 10.31577/caosp.2020.50.2.400
T. Borkovits, S. Rappaport
During the era of Kepler, TESS, and other related star-monitoring space-based missions, quasi-continuous observations of thousands of known and previously unknown eclipsing binaries for several months (or even years) has led to the discovery of hundreds of compact hierarchical triple (and multiple) star systems. Many of them produce spectacular observational effects that were never (or at least, rarely) seen before, for example: extra outer eclipses; thirdbody perturbation-dominated, large amplitude, non-sinusoidal eclipse timing variations; rapid eclipse depth variations, etc. Successful modeling of these phenomena is a great challenge; however, it does offer substantial astrophysical benefits. In this paper we review our two different approaches to these challenges: one of them is based on the analytical theory of third-body perturbations and is applied exclusively to the eclipse timing variations, while the other is a complex, numerical, spectro-photodynamical modeling of all the available observations of such systems. We discuss some recent results obtained for TESS systems.
{"title":"(Not so) hierarchical stellar multiples seen through the eyes of Kepler, TESS, and other missions.","authors":"T. Borkovits, S. Rappaport","doi":"10.31577/caosp.2020.50.2.400","DOIUrl":"https://doi.org/10.31577/caosp.2020.50.2.400","url":null,"abstract":"During the era of Kepler, TESS, and other related star-monitoring space-based missions, quasi-continuous observations of thousands of known and previously unknown eclipsing binaries for several months (or even years) has led to the discovery of hundreds of compact hierarchical triple (and multiple) star systems. Many of them produce spectacular observational effects that were never (or at least, rarely) seen before, for example: extra outer eclipses; thirdbody perturbation-dominated, large amplitude, non-sinusoidal eclipse timing variations; rapid eclipse depth variations, etc. Successful modeling of these phenomena is a great challenge; however, it does offer substantial astrophysical benefits. In this paper we review our two different approaches to these challenges: one of them is based on the analytical theory of third-body perturbations and is applied exclusively to the eclipse timing variations, while the other is a complex, numerical, spectro-photodynamical modeling of all the available observations of such systems. We discuss some recent results obtained for TESS systems.","PeriodicalId":50617,"journal":{"name":"Contributions of the Astronomical Observatory Skalnate Pleso","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89901726","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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