Astrophysics最新文献_第8页

Theory of Classical Gaseous Polytropes in an Integral Representation. II. Analytic Approximations to the Emden Functions and Density Profiles in a Closed Form 积分表示中的经典气体多面体理论。2封闭形式的Emden函数和密度曲线的解析逼近

IF 0.5 4区物理与天体物理

Astrophysics Pub Date : 2023-07-31 DOI: 10.1007/s10511-023-09788-w

G. A. Saiyan

{"title":"Theory of Classical Gaseous Polytropes in an Integral Representation. II. Analytic Approximations to the Emden Functions and Density Profiles in a Closed Form","authors":"G. A. Saiyan","doi":"10.1007/s10511-023-09788-w","DOIUrl":"10.1007/s10511-023-09788-w","url":null,"abstract":"<div><div><p>Analytic approximations are presented for the exact solutions of the Volterra type nonlinear integral equation of the second kind for classical gaseous polytropes in closed form. This equation is considered as the integral equivalent of the Lane-Emden differential equation with boundary conditions which describes the standard polytropic models in terms of a Cauchy problem. With the aid of a linear approximation of this equation and general heuristic considerations of a physical character, as well as with the aid of a graphical model and variation of the parameters of the approximating functions, approximate expressions for the Emden functions and the dimensionless density are obtained in closed form with a mean square accuracy from ~10<sup>-4</sup> to a few percent for a series of values of the polytropic index n of practical interest (n = 0.5, 3, 4, 6, ∞). Our previous approximation for the spatial density of the isothermal model is compared with a pseudo-isothermal law describing the distribution of the density of dark matter surrounding spiral galaxies and used by various authors for studying their rotation curves.</p></div></div>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"66 2","pages":"273 - 289"},"PeriodicalIF":0.5,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5179607","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

Evolution of Spectrum Lines in an Inhomogeneous Atmosphere Illuminated by Nonstationary Energy Sources 非平稳能量照射下非均匀大气中谱线的演化

IF 0.5 4区物理与天体物理

Astrophysics Pub Date : 2023-07-31 DOI: 10.1007/s10511-023-09787-x

A. G. Nikoghossian

引用次数: 0

Features of the Magnetic Field Behavior of the Ae/Be Star HD190073 Ae/Be星HD190073的磁场特性

IF 0.5 4区物理与天体物理

Astrophysics Pub Date : 2023-07-29 DOI: 10.1007/s10511-023-09784-0

Yu.V. Glagolevskij

引用次数: 0

Activity of the Star Gl 414A with Two Planets and its Effect on the Loss of Mass of the Atmosphere of the Planet Gl 414A b 两行星恒星Gl 414A的活动及其对行星Gl 414A b大气质量损失的影响

IF 0.5 4区物理与天体物理

Astrophysics Pub Date : 2023-07-29 DOI: 10.1007/s10511-023-09782-2

I. S. Savanov

{"title":"Activity of the Star Gl 414A with Two Planets and its Effect on the Loss of Mass of the Atmosphere of the Planet Gl 414A b","authors":"I. S. Savanov","doi":"10.1007/s10511-023-09782-2","DOIUrl":"10.1007/s10511-023-09782-2","url":null,"abstract":"<div><div><p>Results are presented from a study of manifestations of the activity of the dwarf Gl 414A of spectral class K7 with two planets, one of which (the planet Gl 414A b) with an eccentricity e=0.45 was found to be within the habitable zone over a large part of its orbit. Our analysis showed that the most reliable determination of the rotation period of Gl 414A was obtained from an analysis of photometric observations of the star in the KELT (Kilodegree Extremely Little Telescope) survey which yield a rotation period of P=42 days. However, the existence of this period is not confirmed by periodograms constructed from other observations of Gl 414A. The long-term activity cycle of the star is on the order of 3800 days (10.4 years). The obtained data on the activity of the star were used to estimate the loss of matter from the atmosphere of the planet Gl 414A b using an approximation formula for a model of atmospheric loss with a limit on energy. Based on 486 estimates of the parameter S<sub>HK</sub>, the loss of matter by the atmosphere of Gl 414A b over an interval of 5805 days (15.9 years) was calculated. The magnitude of these losses mainly lies within a range of log(M<sub>loss</sub>) from 7.15 to 7.50 with a median of 7.30. For an eccentricity of 0.45 the distance from the central star to Gl 414A b ranges from 0.13 to 0.34 a.u., and for these distances the estimated losses of matter by the atmosphere are 16.21·10<sup>17</sup> and 2.37·10<sup>17</sup> g/s, respectively.</p></div></div>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"66 2","pages":"205 - 212"},"PeriodicalIF":0.5,"publicationDate":"2023-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5618261","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

ASASSN-19fy: Features of a Dwarf Nova in the “Period Gap” ASASSN-19fy:“周期间隙”中一颗矮新星的特征

IF 0.5 4区物理与天体物理

Astrophysics Pub Date : 2023-07-29 DOI: 10.1007/s10511-023-09783-1

O. I. Antonyuk, E. P. Pavlenko, K. A. Antonyuk, N. V. Pit, A. A. Sosnovskij, G. I. Kokhirova, F. D. Rakhmatullaeva

引用次数: 0

The First Photometric Study Of The Binary System Css J003106.8+313347 双星系统 Css J003106.8+313347 的首次光度研究

IF 0.5 4区物理与天体物理

Astrophysics Pub Date : 2023-07-27 DOI: 10.54503/0002-3051-2023.76.4-485

E. Paki, Sabrina Baudart, A. Poro

{"title":"The First Photometric Study Of The Binary System Css J003106.8+313347","authors":"E. Paki, Sabrina Baudart, A. Poro","doi":"10.54503/0002-3051-2023.76.4-485","DOIUrl":"https://doi.org/10.54503/0002-3051-2023.76.4-485","url":null,"abstract":"We performed the first photometric study of the CSS J003106.8+313347 W Ursae Majoris (WUMa)-type system based on ground-based observations. We extracted times of minima from our observations and proposed a linear ephemeris based on the increasing incline of the orbital period using a Markov chain Monte Carlo (MCMC) approach. The PHOEBE Python code and the MCMC approach were used for the light curve analysis. This system did not need starspots for the light curve analysis. Mass ratio, fillout factor, and inclination were obtained as 0.699, 0.322, and 60o.6 respectively. We also estimated the absolute parameters of the system using the Gaia DR3 parallax. Therefore, the masses, radii, and luminosities have been determined to be M1 = 1.675, M2 = 1.171, R1 = 1.292, R2 = 1.097, L1 = 1.348, and L2 = 1.221. The orbital angular momentum J0 of the CSS J003106.8+313347 illustrates that this system is located in a region of contact binaries. The positions of the primary and secondary components on the Hertzsprung-Russell (HR) diagram are depicted. Проведено первое фотометрическое исследование системы CSS J003106.8+ 313347 типа W Ursae Majoris (W UMa) на основе наземных наблюдений. Из наших наблюдений извлечены времена минимумов и, используя метод Марковской цепи Монте-Карло (MCMC), предложена линейная эфемерида на основе увеличения наклона орбитального периода. Для анализа кривых блеска использовался код PHOEBE Python и метод MCMC. Для анализа данной системы не потребовалось учитывать звездные пятна. Получены отношение масс, фактор заполнения и наклон, равные 0.699, 0.322 и 60o.6 соответственно. Оценены также абсолютные параметры системы с использованием метода параллаксов Gaia DR3. Таким образом, массы, радиусы и светимости составили M1 = 1.675, M2 = 1.171, R1 = 1.292, R2 = 1.097, L1 = 1.348 и L2 = 1.221. Орбитальный момент импульса (J0) CSS J003106.8+313347 показывает, что эта система находится в области контактных двойных звезд. Положения первичных и вторичных компонентов изображены на диаграмме Герцшпрунга- Рассела (HR).","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"28 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139354273","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

ASASSN-19fy: Особенности карликовой новой в "Провале" периодовCreator: ASASSN-19fy:《失败》中的侏儒新特性:

IF 0.5 4区物理与天体物理

Astrophysics Pub Date : 2023-06-15 DOI: 10.54503/0571-7132-2023.66.2-233

О И Антонюк, Евгений Петрович Павленко, К. А. Антонюк, Н. В. Пить, А. А. Сосновский, Г. И. Кохирова, Ф. Дж. Рахматуллаева

{"title":"ASASSN-19fy: Особенности карликовой новой в \"Провале\" периодов\u0000Creator:","authors":"О И Антонюк, Евгений Петрович Павленко, К. А. Антонюк, Н. В. Пить, А. А. Сосновский, Г. И. Кохирова, Ф. Дж. Рахматуллаева","doi":"10.54503/0571-7132-2023.66.2-233","DOIUrl":"https://doi.org/10.54503/0571-7132-2023.66.2-233","url":null,"abstract":"Фотометрические исследования карликовой новой в \"провале\" периодов ASASSN-19fy были проведены в 2020-2021гг. в течение 24 ночей в Крымской астрофизической обсерватории РАН и трех ночей в Международной астрономической обсерватории Санглох Института астрофизики НАН Республики Таджикистан. Наблюдения охватили сверхвспышку, два повторных поярчания и медленное возвращение к довспышечному состоянию. В течение этого времени наблюдались сверхгорбы, в эволюции которых были выделены стадии развитых сверхгорбов \"В\", их затухания \"С\" и переход между ними.\u0000Photometric investigations of the dwarf nova ASASSN-19fy in the period gap were carried out in 2020-2021 during 24 nights in the Crimean astrophysical observatory of RAS and 3 nights in Sanglokh International astronomical observatory of Institute of Astrophysics, National Academy of Sciences of Tajikistan. Observations covered superoutburst, two rebrightenings and slow return to quiescence. During this time superhumps have been observed. The stage of developed superhumps \"B\", their dying stage \"C\" as well as transition between them were identified.","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"57 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90177853","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 Unified Scheme Of y- Ray Emitting Jetted Active Galactic Nuclei 关于y射线喷射活动星系核的统一方案

IF 0.5 4区物理与天体物理

Astrophysics Pub Date : 2023-06-15 DOI: 10.54503/0571-7132-2023.66.2-169

A. I. Audu, F. C. Odo, E. U. Iyida, O. Okike, A. Ubachukwu

引用次数: 0

Крупномасштабные электрические токи в процессах нагрева короны над активными областями на солнце 在太阳活动区域上空加热日冕的大规模电流

IF 0.5 4区物理与天体物理

Astrophysics Pub Date : 2023-06-15 DOI: 10.54503/0571-7132-2023.66.2-265

Ю. А. Фурсяк

{"title":"Крупномасштабные электрические токи в процессах нагрева короны над активными областями на солнце","authors":"Ю. А. Фурсяк","doi":"10.54503/0571-7132-2023.66.2-265","DOIUrl":"https://doi.org/10.54503/0571-7132-2023.66.2-265","url":null,"abstract":"В работе ставится задача изучить роль крупномасштабных электрических токов, распространяющихся в верхние слои солнечной атмосферы, в процессах нагрева короны Солнца. Для обнаружения и вычисления величины крупномасштабного электрического тока были использованы данные о распределении компонентов вектора магнитного поля в фотосфере, предоставляемые инструментом Helioseismic and Magnetic Imager (HMI) на борту Solar Dynamics Observatory (SDO).\u0000The aim of this paper is to study the role of large-scale electric currents extending into the upper layers of the solar atmosphere in the processes of solar corona heating. To detect and calculate the magnitude of the large-scale electric current, data on the distribution of the magnetic field vector components in the photosphere provided by the Helioseismic and Magnetic Imager (HMI) instrument on board the Solar Dynamics Observatory (SDO) were used.","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76263001","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

Теория классических газовых политроп в интегральном представлении. II. Аналитические приближения функций эмдена и профилей плотности в замкнутом виде 经典气体聚合物理论。II。emden函数的分析近似和闭合密度剖面

IF 0.5 4区物理与天体物理

Astrophysics Pub Date : 2023-06-15 DOI: 10.54503/0571-7132-2023.66.2-301

Григорий Асатурович Саиян

{"title":"Теория классических газовых политроп в интегральном представлении. II. Аналитические приближения функций эмдена и профилей плотности в замкнутом виде","authors":"Григорий Асатурович Саиян","doi":"10.54503/0571-7132-2023.66.2-301","DOIUrl":"https://doi.org/10.54503/0571-7132-2023.66.2-301","url":null,"abstract":"Представлены аналитические приближения точных решений нелинейного интегрального уравнения типа Вольтерры второго рода для классических газовых политроп в замкнутой форме. Это уравнение рассматривается в качестве интегрального эквивалента дифференциального уравнения Лейна-Эмдена с граничными условиями, описывающего известные политропные модели в рамках задачи Коши.\u0000Analytic approximations in closed forms to exact solutions of the nonlinear integral Volterra type equation of the second kind are presented. This equation is considered as the integral equivalent of the Lane-Emden differential equation with boundary conditions, which describes known polytropic models within the Cauchy problem.","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"5 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72938777","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