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Spectral Variations and Physical Conditions of by Draconis in the Ultraviolet 天龙座在紫外线中的光谱变化和物理条件
IF 0.6 4区 物理与天体物理
Astrophysics Pub Date : 2025-04-24 DOI: 10.1007/s10511-025-09857-2
M. R. Sanad
{"title":"Spectral Variations and Physical Conditions of by Draconis in the Ultraviolet","authors":"M. R. Sanad","doi":"10.1007/s10511-025-09857-2","DOIUrl":"10.1007/s10511-025-09857-2","url":null,"abstract":"<p>We present International Ultraviolet Explorer (IUE) observations during the period (1980 - 1994) of the double lined spectroscopic binary BY Dra to show the spectral behavior and physical conditions in its atmosphere. The observations reveal indication of flare activity in their flux values in years (1981-1990-1994) in the chromosphere and transition region of the primary star. Beside the flaring activity the emission lines show a range of variations between high, intermediate and low. There is a relation between the fluxes and rotational phase. The reddening of BY Dra was estimated from 2200 Å absorption feature to be <i>E</i>(<i>B</i> - <i>V</i>) = 0. The average mass loss rate is found to be ~4.9⋅10<sup>-8</sup> <i>M</i><sub>⨀</sub> yr<sup>-1</sup>, the average temperature of the emitting region to be ~9.2⋅10<sup>4</sup> K, energy of flare to be ~6.2⋅10<sup>37</sup> erg. We attributed the spectral variations to a cyclic behavior of the underlying magnetic field and the flaring activity to three component model.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"68 1","pages":"40 - 50"},"PeriodicalIF":0.6,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929944","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}
引用次数: 0
Variability of Planetary Nebulae: Results of Long-Term Observations 行星状星云的变异性：长期观测的结果
IF 0.6 4区 物理与天体物理
Astrophysics Pub Date : 2025-04-24 DOI: 10.1007/s10511-025-09858-1
L. N. Kondratyeva, E. K. Denissyuk, S. A. Shomshekova, I. V. Reva, A. K. Aimanova, M. A. Krugov
{"title":"Variability of Planetary Nebulae: Results of Long-Term Observations","authors":"L. N. Kondratyeva,&nbsp;E. K. Denissyuk,&nbsp;S. A. Shomshekova,&nbsp;I. V. Reva,&nbsp;A. K. Aimanova,&nbsp;M. A. Krugov","doi":"10.1007/s10511-025-09858-1","DOIUrl":"10.1007/s10511-025-09858-1","url":null,"abstract":"<p>The results of spectroscopic and photometric observations of 14 compact planetary nebulae are presented. Observations were conducted at the V.G. Fesenkov Astrophysical Institute (Kazakhstan) since 1973. The aim of this study is to obtain data on the variability of the studied objects over long time spans. The criterion for determining the nebular excitation class was the intensity of the [OIII] lines normalized to the intensity of Hβ. Analysis of the data collected over 40–50 years revealed significant spectral changes in most of the observed objects, likely associated with an increase in the temperature of the central stars and/or changes in the internal structure of the nebular envelopes.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"68 1","pages":"51 - 68"},"PeriodicalIF":0.6,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929945","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}
引用次数: 0
Astrometric and Photometric Studies for Some Selected Open Star Clusters 一些选定疏散星团的天文测量和光度研究
IF 0.6 4区 物理与天体物理
Astrophysics Pub Date : 2025-04-23 DOI: 10.1007/s10511-025-09855-4
R. M. Hariry, A. A. Haroon, A. A. Malawi
{"title":"Astrometric and Photometric Studies for Some Selected Open Star Clusters","authors":"R. M. Hariry,&nbsp;A. A. Haroon,&nbsp;A. A. Malawi","doi":"10.1007/s10511-025-09855-4","DOIUrl":"10.1007/s10511-025-09855-4","url":null,"abstract":"<p>In this study, we conducted a detailed astrometric, and photometric study of four open clusters (SAI 43, SAI 47, SAI 63, and SAI 113) using data from Gaia DR3. The ASteCA code enabled the identification of the astrometric and photometric parameters. The new centers of these clusters were redetermined and from Radial Density Profile (RDP), the cluster radii, are between 3.13- and 6.6 arcmin for all clusters. The astrophysical parameters are as follows: the number of star members N are 141 (SAI 43), 153 (SAI 47), 198 (SAI 63), and 188 (SAI 113); parallax (ϖ) for SAI 43, SAI 47, SAI 63, and SAI 113 are between 0.275 and 0.506 mas; proper motion parameters (μ<sub><i>a</i></sub> cosδ, μ<sub>δ</sub>) are (0.57, -0.54 mas/yr), (0, -0.34 mas/yr), (-0.24, 0.26 mas/yr), and (-5.61, 2.84 mas/yr) for SAI 43, SAI 47, SAI 63, and SAI 113, respectively. The photometric parameters include the color magnitude diagram (CMD), ages, reddening, and distances. The ages are provided as log (age), and they are between (7.172-8.659); the color excess E(B-V) is 0.476±0.017 mag for SAI 43, 0.375±0.014 mag for SAI 47, 0.510±0.009 mag for SAI 63, and 1.265±0.011 mag for SAI 113, the distance modules of the clusters are between 11.177-13.439 mag, and the distances from the sun to each of the clusters (SAI 43, SAI 47, SAI 63, and SAI 113) are calculated as 4900±100 pc, 2360±30 pc, 1720±20 pc, and 3720±50 pc, respectively.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"68 1","pages":"17 - 31"},"PeriodicalIF":0.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929942","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}
引用次数: 0
Total C+N+O Abundances in the Atmospheres of Red Giants of Different Metallicities 不同金属丰度红巨星大气中C+N+O的总丰度
IF 0.6 4区 物理与天体物理
Astrophysics Pub Date : 2025-04-23 DOI: 10.1007/s10511-025-09856-3
L. S. Lyubimkov, D. V. Petrov
{"title":"Total C+N+O Abundances in the Atmospheres of Red Giants of Different Metallicities","authors":"L. S. Lyubimkov,&nbsp;D. V. Petrov","doi":"10.1007/s10511-025-09856-3","DOIUrl":"10.1007/s10511-025-09856-3","url":null,"abstract":"<p>The sum of C+N+O in red giants presents interest due to its steady nature during stellar evolution of the star, although the abundance of its components, especially C and N, undergoes significant evolutionary changes. It is shown that there is a pronounced correlation between the total log ε(C+N+O) abundances in red giants and their metallicity index [Fe/H]. The linear relationship between log ε (C + N + O) and [Fe/H] indicates an increase in log ε (C+N+O) from 7.0 with [Fe/H] = -2.5 to 9.2 with [Fe/H] = +0.3, i.e., by more than 2 dex. In contrast, the abundance of (C+N+O) relative to Fe decreases by 0.7 dex over the same [Fe/H] interval. It is shown that the ratio between [(C+N+O)/Fe] and [Fe/H] is almost completely determined by the ratio between [O/Fe] and [Fe/H]; hence, it is confirmed that oxygen is the main contributor to C+N+O. Since current models of Galactic evolution explain the observed dependence of [O/Fe] on [Fe/H] reasonably well, they thereby also explain the observed dependence of [(C+N+O)/Fe] on [Fe/H].</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"68 1","pages":"32 - 39"},"PeriodicalIF":0.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929943","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}
引用次数: 0
Guram Nikolayevich Salukvadze (1931–2024) 古拉姆·尼古拉耶维奇·萨卢克瓦泽（1931-2024）
IF 0.6 4区 物理与天体物理
Astrophysics Pub Date : 2025-04-23 DOI: 10.1007/s10511-025-09853-6
{"title":"Guram Nikolayevich Salukvadze (1931–2024)","authors":"","doi":"10.1007/s10511-025-09853-6","DOIUrl":"10.1007/s10511-025-09853-6","url":null,"abstract":"","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"68 1","pages":"1 - 2"},"PeriodicalIF":0.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143930095","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}
引用次数: 0
Ray Properties of Blazars 耀变体的射线特性
IF 0.6 4区 物理与天体物理
Astrophysics Pub Date : 2025-04-23 DOI: 10.1007/s10511-025-09854-5
G. M. Paronyan
{"title":"Ray Properties of Blazars","authors":"G. M. Paronyan","doi":"10.1007/s10511-025-09854-5","DOIUrl":"10.1007/s10511-025-09854-5","url":null,"abstract":"<p>An analysis of the blazar sample from the BZCAT catalog reveals that these objects exhibit such special properties, as strong radio emission, optical and radio variability, continuous optical spectra, polarization, and high luminosity, among others. Initially, the catalog included objects with optical variability and strong radio emission, specifically BL Lacertae (BLL) objects and flat-spectrum radio quasars (FSRQ)). Along with the above properties, 48% of blazars produce X-ray emission. This study investigates the X-ray properties and other characteristics of blazars determined through our analyses and calculations.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"68 1","pages":"3 - 16"},"PeriodicalIF":0.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143930146","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}
引用次数: 0
Activity Cycles of dM4e Dwarf GJ 1243 dM4e矮星GJ 1243的活动周期
IF 0.6 4区 物理与天体物理
Astrophysics Pub Date : 2025-01-20 DOI: 10.1007/s10511-025-09844-7
E. S. Dmitrienko, I. S. Savanov
{"title":"Activity Cycles of dM4e Dwarf GJ 1243","authors":"E. S. Dmitrienko,&nbsp;I. S. Savanov","doi":"10.1007/s10511-025-09844-7","DOIUrl":"10.1007/s10511-025-09844-7","url":null,"abstract":"<p>The dM4e dwarf GJ 1243 (KIC 9726699) has been a subject of extensive research due to its unique flare activity and the evolution of spots on its surface. This paper presents the results of a study into the long-term activity cycles of this star, derived from archival photometric time series. Observations from three independent surveys in different photometric filters indicate long-timescale variability in the luminosity of GJ 1243, with four characteristic cycle durations (we will number them from 1 to 4), clustered around the following <i>P</i><sub><i>cycl</i></sub> values (1 to 3): 1.5 years, 2.6 years, and 6.3 years, respectively, and near <i>P</i><sub><i>cycl</i></sub> (4) of the order of 12.3–12.6 years. A detailed analysis of the GJ 1243 data on the logarithmic <i>P</i><sub><i>cycl</i></sub>/<i>P</i><sub><i>rot</i></sub> versus 1/<i>P</i><sub><i>rot</i></sub> diagram and comparisons with other M dwarfs reveal a unified relationship for short cycles across the studied stars.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"67 4","pages":"454 - 462"},"PeriodicalIF":0.6,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109134","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}
引用次数: 0
On the Extended Blazar Sequence for γ-Ray Emitting Active Galactic Nuclei γ射线发射活动星系核的扩展耀变体序列
IF 0.6 4区 物理与天体物理
Astrophysics Pub Date : 2025-01-18 DOI: 10.1007/s10511-025-09843-8
A. I. Audu, F. C. Odo, A. A. Ubachukwu
{"title":"On the Extended Blazar Sequence for γ-Ray Emitting Active Galactic Nuclei","authors":"A. I. Audu,&nbsp;F. C. Odo,&nbsp;A. A. Ubachukwu","doi":"10.1007/s10511-025-09843-8","DOIUrl":"10.1007/s10511-025-09843-8","url":null,"abstract":"<p>In this paper, we use the distributions of observed γ-ray properties, as well as orientation parameters of a sample of Fermi-LAT AGNs to investigate the hypothesis that γ-NLS1 objects are beamed sources with γ-ray emitting axes inclined at close angles to the line of sight. Based on these parameters we investigate the relationship between γ-NLS1s and other subclasses of γ[-ray emitting jetted AGNs. Results show that γ-NLS1s are more highly beamed than both FSRQs and BL Lacs with mean value of core-dominance parameter <i>R</i><sub><i>g</i></sub> ~ 9507. γ-NLS1s and jetted Seyfert galaxies are continuous in distribution of the orientation parameter with average cone angles Φ<sub><i>m</i></sub> ~ 8° and 44° respectively. Furthermore, the spectral energy distribution of γ-NLS1 is comparable to those of FSRQs and BL Lacs suggestive that γ-NLS1s and blazars form a continuous spectral sequence. There is a significant anti-correlation (<i>r</i> ~ -0.9) between the γ-ray dominance <i>D</i><sub><i>g</i></sub> and γ-ray luminosity. There is a strong dependence of <i>D</i><sub><i>g</i></sub> on redshift (<i>r</i> ~ -0.7) suggestive that <i>D</i><sub><i>g</i></sub> is more sensitive to environmental factors than intrinsic γ-ray luminosity. The results suggest that γ-NLS1s are highly beamed γ-ray sources whose de-beamed counterparts can be found among Seyfert galaxy populations.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"67 4","pages":"440 - 453"},"PeriodicalIF":0.6,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108844","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}
引用次数: 0
Activity of the Star TOI-6255 and Atmospheric Mass Loss from its Planet 恒星TOI-6255的活动及其行星的大气质量损失
IF 0.6 4区 物理与天体物理
Astrophysics Pub Date : 2025-01-17 DOI: 10.1007/s10511-025-09846-5
I. S. Savanov
{"title":"Activity of the Star TOI-6255 and Atmospheric Mass Loss from its Planet","authors":"I. S. Savanov","doi":"10.1007/s10511-025-09846-5","DOIUrl":"10.1007/s10511-025-09846-5","url":null,"abstract":"<p>We considered the planetary system of TOI-6255, in which an Earth-like planet with an extremely short period of 5.7 hours orbits an M dwarf. Based on archival measurements of TOI-6255 brightness we established rotation-induced light variability and periodic long-term variability of the object. Possible rotation period P of the star falls within the periods of 64–74 days and 78–92 days. The results were compared with those reported in the literature. For two values of logR'<sub>HK</sub> (-5.15 and -4.66), corresponding to the peaks of the bimodal distribution of this parameter for low-activity and active M dwarfs, the atmospheric mass loss rates of the planet TOI-6255 b were estimated: 4.9 · 10<sup>9</sup> g/s for logR'<sub>HK</sub> = - 4.66, and 1.1 · 10<sup>9</sup> g/s for logR'<sub>HK</sub> = - 5.15. We determined the promise of TOI-6255 b to become a high priority subject for future research.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"67 4","pages":"479 - 486"},"PeriodicalIF":0.6,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108759","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}
引用次数: 0
Quantitative Analysis of the Spectra of CQ Tau and UX Ori Stars Outside Eclipses According to the Nordic Optical Telescope Data 根据北欧光学望远镜数据对日蚀外CQ Tau和UX Ori恒星光谱的定量分析
IF 0.6 4区 物理与天体物理
Astrophysics Pub Date : 2025-01-17 DOI: 10.1007/s10511-025-09845-6
P. Dimitrieva, O. V. Kozlova
{"title":"Quantitative Analysis of the Spectra of CQ Tau and UX Ori Stars Outside Eclipses According to the Nordic Optical Telescope Data","authors":"P. Dimitrieva,&nbsp;O. V. Kozlova","doi":"10.1007/s10511-025-09845-6","DOIUrl":"10.1007/s10511-025-09845-6","url":null,"abstract":"<p>A quantitative analysis of the spectra of CQ Tau and UX Ori stars belonging to the family of young irregular variable stars with Algol-like decrease in brightness has been performed. The spectra were obtained at the Nordic Optical Telescope (NOT) observatory at times when the stars were in a bright state. On their basis, the equivalent widths of the photospheric absorption lines, as well as the Hα emission line, are determined. The equivalent width of the latter is used to estimate the gas accretion rate on the stars.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"67 4","pages":"463 - 478"},"PeriodicalIF":0.6,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108760","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}
引用次数: 0
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