Abstract We present the PRESTALINE package, a novel tool to simulate and analyse spectra of star forming objects. PRESTALINE allows for a direct comparison of theoretical models with observations and simplifies an analysis of observed spectra. This allows researchers to estimate physical conditions in a studied object and to interpret its chemical composition in a quantitative way. The goal of the project is to set up a consistent framework which would bridge a gap between theoretical studies and observations of star forming regions. In this paper, we present the results of applying PRESTALINE to the test object DR21(OH) and discuss the project general possibilities.
{"title":"PRESTALINE: a package for simulation and analysis of molecular spectra of star forming regions","authors":"G. Van Looveren, O. Kochina, D. Wiebe","doi":"10.1515/astro-2021-0012","DOIUrl":"https://doi.org/10.1515/astro-2021-0012","url":null,"abstract":"Abstract We present the PRESTALINE package, a novel tool to simulate and analyse spectra of star forming objects. PRESTALINE allows for a direct comparison of theoretical models with observations and simplifies an analysis of observed spectra. This allows researchers to estimate physical conditions in a studied object and to interpret its chemical composition in a quantitative way. The goal of the project is to set up a consistent framework which would bridge a gap between theoretical studies and observations of star forming regions. In this paper, we present the results of applying PRESTALINE to the test object DR21(OH) and discuss the project general possibilities.","PeriodicalId":19514,"journal":{"name":"Open Astronomy","volume":"30 1","pages":"96 - 102"},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43619863","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}
Abstract A large number of galaxies have large-scale magnetic fields which are usually measured by the Faraday rotation of radio waves. Their origin is usually connected with the dynamo mechanism which is based on differential rotation of the interstellar medium and alpha-effect characterizing the helicity of the small-scale motions. However, it is necessary to have initial magnetic field which cannot be generated by the dynamo. One of the possible mechanisms is connected with the Biermann battery which acts because of different masses of protons and electrons passing from the central object. They produce circular currents which induce the vertical magnetic field. As for this field we can obtain the integral equation which can be solved by simulated annealing method which is widely used in different branches of mathematics
{"title":"Biermann battery as a source of astrophysical magnetic fields","authors":"E. Mikhailov, R. Andreasyan","doi":"10.1515/astro-2021-0017","DOIUrl":"https://doi.org/10.1515/astro-2021-0017","url":null,"abstract":"Abstract A large number of galaxies have large-scale magnetic fields which are usually measured by the Faraday rotation of radio waves. Their origin is usually connected with the dynamo mechanism which is based on differential rotation of the interstellar medium and alpha-effect characterizing the helicity of the small-scale motions. However, it is necessary to have initial magnetic field which cannot be generated by the dynamo. One of the possible mechanisms is connected with the Biermann battery which acts because of different masses of protons and electrons passing from the central object. They produce circular currents which induce the vertical magnetic field. As for this field we can obtain the integral equation which can be solved by simulated annealing method which is widely used in different branches of mathematics","PeriodicalId":19514,"journal":{"name":"Open Astronomy","volume":"30 1","pages":"127 - 131"},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67441284","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}
Abstract Traditional atmospheric models are based on the analysis and fitting of various factors influencing the space atmosphere density. Neural network models do not specifically analyze the polynomials of each influencing factor in the atmospheric model, but use large data sets for network construction. Two traditional atmospheric model algorithms are analyzed, the main factors affecting the atmospheric model are identified, and an atmospheric model based on neural networks containing various influencing factors is proposed. According to the simulation error, the Levenberg-Marquardt algorithm is used to iteratively realize the rapid network weight correction, and the optimal neural network atmospheric model is obtained. The space atmosphere is simulated and calculated with an atmospheric model based on neural networks, and its average error rate is lower than that of traditional atmospheric models such as the DTM2013 model and the MSIS00 model. At the same time, the calculation complexity of the atmospheric model based on the neural networks is significantly simplified than that of the traditional atmospheric model.
{"title":"The atmospheric model of neural networks based on the improved Levenberg-Marquardt algorithm","authors":"Wenhui Cui, W. Qu, Min Jiang, Gang Yao","doi":"10.1515/astro-2021-0003","DOIUrl":"https://doi.org/10.1515/astro-2021-0003","url":null,"abstract":"Abstract Traditional atmospheric models are based on the analysis and fitting of various factors influencing the space atmosphere density. Neural network models do not specifically analyze the polynomials of each influencing factor in the atmospheric model, but use large data sets for network construction. Two traditional atmospheric model algorithms are analyzed, the main factors affecting the atmospheric model are identified, and an atmospheric model based on neural networks containing various influencing factors is proposed. According to the simulation error, the Levenberg-Marquardt algorithm is used to iteratively realize the rapid network weight correction, and the optimal neural network atmospheric model is obtained. The space atmosphere is simulated and calculated with an atmospheric model based on neural networks, and its average error rate is lower than that of traditional atmospheric models such as the DTM2013 model and the MSIS00 model. At the same time, the calculation complexity of the atmospheric model based on the neural networks is significantly simplified than that of the traditional atmospheric model.","PeriodicalId":19514,"journal":{"name":"Open Astronomy","volume":"30 1","pages":"24 - 35"},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44357716","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}
Abstract During the 40-year photographic period of astronomical observations, the Baldone Astrophysical Observatory has accumulated more than 22,000 direct and 2,500 spectral images. In 2018, the digitization of direct astrophoto images with a resolution of 1200 dpi was completed. A processing methodology for obtaining the equatorial coordinates and photometric characteristics of the objects recorded in digitized astronegatives using the LINUX/MIDAS/ROMAFOT environment has been developed at the Main Astronomical Observatory of the National Academy of Sciences of Ukraine. Program package with success already works in seven observatories. A description of the operation of this program complex in stages and analysis of the obtained results is given. The steps describe the astrometric and photometric reduction process of digital records, as well as the reduction of the obtained instrumental magnitudes to the Johnson UBVR photometric system. The methodology of characteristic curve construction in the case of one exposure is described in detail. From all digitized astrophotoplates to date Approximately 2200 V film negatives, 300 U plates and several R, B plates were processed. As a result, catalogs of the positions and magnitudes of Pluto, 1848 asteroids and comets were obtained. 31 new positions were recorded in the VizieR Pluto catalog VI/155. It was found that the root-mean-square errors of the reduction of the measured coordinates to the equatorial coordinate system of the Tycho-2 catalog have values σRA,DEC= 0.1-0.2”, and the root-mean-square errors of the reduction of instrumental photometric quantities m to the Johnson system of stellar UBVR-values are also in within σUBVR = 0.1 − 0.2m.
{"title":"Astrometry and photometry of digitized plates of Baldone Schmidt telescope","authors":"I. Eglitis, V. Andruk","doi":"10.1515/astro-2021-0002","DOIUrl":"https://doi.org/10.1515/astro-2021-0002","url":null,"abstract":"Abstract During the 40-year photographic period of astronomical observations, the Baldone Astrophysical Observatory has accumulated more than 22,000 direct and 2,500 spectral images. In 2018, the digitization of direct astrophoto images with a resolution of 1200 dpi was completed. A processing methodology for obtaining the equatorial coordinates and photometric characteristics of the objects recorded in digitized astronegatives using the LINUX/MIDAS/ROMAFOT environment has been developed at the Main Astronomical Observatory of the National Academy of Sciences of Ukraine. Program package with success already works in seven observatories. A description of the operation of this program complex in stages and analysis of the obtained results is given. The steps describe the astrometric and photometric reduction process of digital records, as well as the reduction of the obtained instrumental magnitudes to the Johnson UBVR photometric system. The methodology of characteristic curve construction in the case of one exposure is described in detail. From all digitized astrophotoplates to date Approximately 2200 V film negatives, 300 U plates and several R, B plates were processed. As a result, catalogs of the positions and magnitudes of Pluto, 1848 asteroids and comets were obtained. 31 new positions were recorded in the VizieR Pluto catalog VI/155. It was found that the root-mean-square errors of the reduction of the measured coordinates to the equatorial coordinate system of the Tycho-2 catalog have values σRA,DEC= 0.1-0.2”, and the root-mean-square errors of the reduction of instrumental photometric quantities m to the Johnson system of stellar UBVR-values are also in within σUBVR = 0.1 − 0.2m.","PeriodicalId":19514,"journal":{"name":"Open Astronomy","volume":"30 1","pages":"12 - 23"},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/astro-2021-0002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44058674","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}
N. Samus, E. Kazarovets, O. V. Durlevich, Natalia N. Kireeva, E. Pastukhova, Anton V. Khruslov
Abstract We briefly outline the history of the General Catalogue of Variable Stars (GCVS) and the New Catalogue of Suspected Variable Stars (NSV catalogue). Recently, we have completed a revision of the NSV catalogue. Positional information was checked for all its stars and, in many cases, new photometric data were added. As a result, one third of all NSV stars have been transferred to the GCVS. Having determined equatorial coordinates for variable stars in globular star clusters, we began to add them to the GCVS. Two Name-lists published so far contain more than 1700 variable stars in 36 globular clusters; an additional Name-list (about 900 variable stars in 27 globular clusters) will be published before the end of 2021. We discuss problem cases in the literature and in the Catalogue of Variable Stars in Galactic Globular Clusters revealed during our preparation of the Name-lists. The future of traditional catalogues of variable stars (GCVS; AAVSO Variable-star Data Index VSX) is discussed.
{"title":"Future of the General Catalogue of Variable Stars from the Experience of Recent Name-lists","authors":"N. Samus, E. Kazarovets, O. V. Durlevich, Natalia N. Kireeva, E. Pastukhova, Anton V. Khruslov","doi":"10.1515/astro-2021-0016","DOIUrl":"https://doi.org/10.1515/astro-2021-0016","url":null,"abstract":"Abstract We briefly outline the history of the General Catalogue of Variable Stars (GCVS) and the New Catalogue of Suspected Variable Stars (NSV catalogue). Recently, we have completed a revision of the NSV catalogue. Positional information was checked for all its stars and, in many cases, new photometric data were added. As a result, one third of all NSV stars have been transferred to the GCVS. Having determined equatorial coordinates for variable stars in globular star clusters, we began to add them to the GCVS. Two Name-lists published so far contain more than 1700 variable stars in 36 globular clusters; an additional Name-list (about 900 variable stars in 27 globular clusters) will be published before the end of 2021. We discuss problem cases in the literature and in the Catalogue of Variable Stars in Galactic Globular Clusters revealed during our preparation of the Name-lists. The future of traditional catalogues of variable stars (GCVS; AAVSO Variable-star Data Index VSX) is discussed.","PeriodicalId":19514,"journal":{"name":"Open Astronomy","volume":"30 1","pages":"122 - 126"},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46304175","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}
P. Fűtő, J. Vanyó, I. Simonia, J. Sztakovics, M. Nagy, A. Gucsik, B. Döncző, Z. Kertész, Richárd Novák, Á. Csámer
Abstract Kaba meteorite as a reference material (one of a least metamorphosed and most primitive carbonaceous chondrites fell on Earth) was chosen for this study providing an adequate background for study of the protoplanetary disk or even the crystallization processes of the Early Solar System. Its olivine minerals (forsterite and fayalite) and their Mg/Fe ratio can help us to understand more about the planet formation mechanism and whether or not the metallic constitutes of the disk could be precursors for the type of planets in the Solar System. A multiple methodological approach such as a combination of the scanning electron microscope, optical microscope, Raman spectroscopy and electron microprobe of the olivine grains give the Fe/Mg ratio database. The analyses above confirmed that planet formation in the protoplanetary disk is driven by the mineralogical precursors of the crystallization process. On the other hand, four nebulae mentioned in this study provide the astronomical data confirming that the planet formation in the protoplanetary disk is dominated or even driven by the metallic constituents.
{"title":"The Mg/Fe ratio of silicate minerals in the meteoritic materials and in the circumstellar environment: A case study for the chondritic-like composition","authors":"P. Fűtő, J. Vanyó, I. Simonia, J. Sztakovics, M. Nagy, A. Gucsik, B. Döncző, Z. Kertész, Richárd Novák, Á. Csámer","doi":"10.1515/astro-2021-0006","DOIUrl":"https://doi.org/10.1515/astro-2021-0006","url":null,"abstract":"Abstract Kaba meteorite as a reference material (one of a least metamorphosed and most primitive carbonaceous chondrites fell on Earth) was chosen for this study providing an adequate background for study of the protoplanetary disk or even the crystallization processes of the Early Solar System. Its olivine minerals (forsterite and fayalite) and their Mg/Fe ratio can help us to understand more about the planet formation mechanism and whether or not the metallic constitutes of the disk could be precursors for the type of planets in the Solar System. A multiple methodological approach such as a combination of the scanning electron microscope, optical microscope, Raman spectroscopy and electron microprobe of the olivine grains give the Fe/Mg ratio database. The analyses above confirmed that planet formation in the protoplanetary disk is driven by the mineralogical precursors of the crystallization process. On the other hand, four nebulae mentioned in this study provide the astronomical data confirming that the planet formation in the protoplanetary disk is dominated or even driven by the metallic constituents.","PeriodicalId":19514,"journal":{"name":"Open Astronomy","volume":"30 1","pages":"45 - 55"},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48894124","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}
Abstract Observations in the near-infrared wavelength range have been regularly carried out at the Crimean Astrophysical Observatory (CrAO) on the Tower Solar Telescope (TST-2). It began in the late 1990s by putting into operation the Universal Spectrophotometer (USPh) at the TST-2 and it continues up to the present time. In 2020 the observation process was modernized - the mirror control electronics and software were replaced. Work is currently underway to create a catalog of solar disk images obtained before the modernization of TST-2. Here we present fragments of the catalog - several examples of a full solar disk in He i 1083 nm from the USPh/TST-2 instrument and a brief description of the future catalog.
克里米亚天体物理天文台(CrAO)在塔式太阳望远镜(st -2)上定期进行近红外波段的观测。它始于20世纪90年代末，在sts -2上投入使用了通用分光光度计(USPh)，并一直持续到现在。2020年，观测过程实现了现代化——更换了镜子控制电子设备和软件。目前正在进行的工作是创建一个在TST-2现代化之前获得的太阳盘图像目录。在这里，我们展示了该目录的一些片段——来自USPh/ st -2仪器的He i 1083 nm的完整太阳盘的几个例子，以及对未来目录的简要描述。
{"title":"The near-infrared observations at the Tower Solar Telescope TST-2 of the Crimean Astrophysical Observatory","authors":"O. Andreeva, V. Malashchuk","doi":"10.1515/astro-2021-0030","DOIUrl":"https://doi.org/10.1515/astro-2021-0030","url":null,"abstract":"Abstract Observations in the near-infrared wavelength range have been regularly carried out at the Crimean Astrophysical Observatory (CrAO) on the Tower Solar Telescope (TST-2). It began in the late 1990s by putting into operation the Universal Spectrophotometer (USPh) at the TST-2 and it continues up to the present time. In 2020 the observation process was modernized - the mirror control electronics and software were replaced. Work is currently underway to create a catalog of solar disk images obtained before the modernization of TST-2. Here we present fragments of the catalog - several examples of a full solar disk in He i 1083 nm from the USPh/TST-2 instrument and a brief description of the future catalog.","PeriodicalId":19514,"journal":{"name":"Open Astronomy","volume":"30 1","pages":"225 - 227"},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48151237","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}
Abstract The possibility of analyzing the line of sight (LOS) velocity and its gradient at each point of the Hinode SOT/SP maps using bisector analysis is revealed. A technique for obtaining such gradient is described. To estimate the velocity gradient, it is necessary to know both the velocity value and the layer height to which the bisector point is responded. We have constructed and tested a method to determine this height. We found velocities at the same heights for lines Fe I λ 6301, 6302 Å averaged over the whole map. It turned out that these velocities have some difference that changes with height and time. The error in the estimating of average velocity for the whole map is 2 m·s−1. It follows that the wavelengths of lines 6301 and 6302 given in the NIST tables may differ from the real ones at 5.5 mÅ. Or there is an inaccuracy in the spectrograph dispersion specified in the FITS files. As an example, the curves of changes with the height of the LOS velocity and its gradient were constructed both for points of the whole map and for subsets of the hottest and coldest points.
摘要揭示了利用平分线分析法分析Hinode SOT/SP地图各点视距速度及其梯度的可能性。描述了一种获得这种梯度的技术。为了估计速度梯度，必须同时知道速度值和等分点响应的层高。我们已经构建并测试了一种方法来确定这个高度。我们发现在相同高度的速度线Fe I λ 6301, 6302 Å平均在整个地图上。结果是这些速度有一些随高度和时间变化的差异。整个地图的平均速度估计误差为2 m·s−1。由此可见，NIST表格中给出的6301和6302线的波长可能与实际波长5.5 mÅ有所不同。或者在FITS文件中指定的光谱仪色散不准确。以整幅图的点和最热点和最冷点的子集为例，分别构建了随LOS速度高度及其梯度的变化曲线。
{"title":"Possibilities of velocity field analysis from Hinode SOT/SP data","authors":"S. G. Mozharovsky","doi":"10.1515/astro-2021-0026","DOIUrl":"https://doi.org/10.1515/astro-2021-0026","url":null,"abstract":"Abstract The possibility of analyzing the line of sight (LOS) velocity and its gradient at each point of the Hinode SOT/SP maps using bisector analysis is revealed. A technique for obtaining such gradient is described. To estimate the velocity gradient, it is necessary to know both the velocity value and the layer height to which the bisector point is responded. We have constructed and tested a method to determine this height. We found velocities at the same heights for lines Fe I λ 6301, 6302 Å averaged over the whole map. It turned out that these velocities have some difference that changes with height and time. The error in the estimating of average velocity for the whole map is 2 m·s−1. It follows that the wavelengths of lines 6301 and 6302 given in the NIST tables may differ from the real ones at 5.5 mÅ. Or there is an inaccuracy in the spectrograph dispersion specified in the FITS files. As an example, the curves of changes with the height of the LOS velocity and its gradient were constructed both for points of the whole map and for subsets of the hottest and coldest points.","PeriodicalId":19514,"journal":{"name":"Open Astronomy","volume":"30 1","pages":"203 - 209"},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44809877","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}
A. Mickaelian, G. Mikayelyan, H. Abrahamyan, G. Paronyan, O. Malkov
Abstract This article is a presentation of a project which is a statistical study of white dwarfs’ properties carried out based on the sample of the First Byurakan Survey Blue Stellar Objects (FBS BSOs) and the Catalogue of White Dwarfs. Using these results, we have searched and will continue to search for new white dwarfs by means of Gaia accurate astrometry. The discovery and study of new White Dwarfs (WDs) is extremely important for understanding the kinematics and dynamics of the local stellar population. They are evolutionary signatures of the Milky Way, as most of stars pass through this evolutionary stage. We have carried out a statistical analysis of the White Dwarfs Catalogue to establish their average physical properties. Based on these data, we have searched for new WDs using Gaia EDR3 accurate astrometry. It provides huge amount of data to confirm WDs and reveal many more such objects. Gaia’s astrometric accuracy allows more detailed studies of WDs and many other stars. Using Gaia accurate data in combination with SDSS and DFBS low-dispersion spectra and additional multiwavelength data, we have revealed many new WDs. Many of them are subject for studies on binarity and variability (including a number of subtypes, e.g. ZZ Ceti stars (pulsating WDs), cataclysmic variables, etc.). WDs among FBS blue stellar objects at high galactic latitudes have been searched and revealed. Search for high galactic latitude WDs in DFBS have also been carried out. Using the revealed and calculated characteristics, a statistical study of WD properties is being done.
{"title":"Absolute magnitudes of white dwarfs and discovery of new white dwarfs from FBS Blue Stellar Objects by means of Gaia EDR3 data","authors":"A. Mickaelian, G. Mikayelyan, H. Abrahamyan, G. Paronyan, O. Malkov","doi":"10.1515/astro-2021-0027","DOIUrl":"https://doi.org/10.1515/astro-2021-0027","url":null,"abstract":"Abstract This article is a presentation of a project which is a statistical study of white dwarfs’ properties carried out based on the sample of the First Byurakan Survey Blue Stellar Objects (FBS BSOs) and the Catalogue of White Dwarfs. Using these results, we have searched and will continue to search for new white dwarfs by means of Gaia accurate astrometry. The discovery and study of new White Dwarfs (WDs) is extremely important for understanding the kinematics and dynamics of the local stellar population. They are evolutionary signatures of the Milky Way, as most of stars pass through this evolutionary stage. We have carried out a statistical analysis of the White Dwarfs Catalogue to establish their average physical properties. Based on these data, we have searched for new WDs using Gaia EDR3 accurate astrometry. It provides huge amount of data to confirm WDs and reveal many more such objects. Gaia’s astrometric accuracy allows more detailed studies of WDs and many other stars. Using Gaia accurate data in combination with SDSS and DFBS low-dispersion spectra and additional multiwavelength data, we have revealed many new WDs. Many of them are subject for studies on binarity and variability (including a number of subtypes, e.g. ZZ Ceti stars (pulsating WDs), cataclysmic variables, etc.). WDs among FBS blue stellar objects at high galactic latitudes have been searched and revealed. Search for high galactic latitude WDs in DFBS have also been carried out. Using the revealed and calculated characteristics, a statistical study of WD properties is being done.","PeriodicalId":19514,"journal":{"name":"Open Astronomy","volume":"30 1","pages":"210 - 215"},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42236091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Introduction to the Special Issue “The Global Space Exploration Conference (GLEX) 2021”","authors":"P. Ehrenfreund","doi":"10.1515/astro-2021-0005","DOIUrl":"https://doi.org/10.1515/astro-2021-0005","url":null,"abstract":"","PeriodicalId":19514,"journal":{"name":"Open Astronomy","volume":"30 1","pages":"36 - 36"},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42602569","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：