Astrophysics最新文献

{"title":"Activity of the Star TOI-784 and Loss of Atmospheric Mass by Its Planet","authors":"I. S. Savanov","doi":"10.1007/s10511-024-09815-4","DOIUrl":"10.1007/s10511-024-09815-4","url":null,"abstract":"<p>The properties of the planetary system TOI-784, in which an earth-like planet orbits a low-activity star of solar type, are examined. Archived V-band measurements of the brightness of TOI-784 in the ASAS 4 data base do not yield reliable indications about the variability of the brightness owing to rotation or about the cyclical long-term variability of this object. A possible estimate of the magnitude of the rotation period of the star is <i>Prot</i>/sini = 41.7 ± 11.4 days. The age of the system according to the empirical gyrochronological relations equals 7.8±3.4 billion years. The average value of the atmospheric activity parameter log<i>R</i>′_<i>HK</i> = – 4.99 which corresponds to the level of low-activity stars with analogous (<i>B</i>-<i>V</i>) color index is found and is close to that of the sun. The radius of the planet TOI-784 b is equal to 1.93 <i>R</i>_⊕, its mass is 9.67 <i>M</i>_⊕, and its average density is 7.4 g/cm³ (the planet is rocky). An estimate of the loss of matter from the atmosphere of the planet TOI-784 b was obtained from an approximate formula corresponding to a model of loss by the atmosphere with a limit on energy. Calculations have shown that the rate of loss of matter by the atmosphere of the planet is 4.7 ⋅ 10⁸ g/s. The relatively low rate of loss of matter by the planet’s atmosphere, despite a high effective temperature of the star’s atmosphere and the closeness of the planet to the star, is probably related to a low level of activity of the star.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140964639","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":"Induced Electromagnetic Radiation from a Charged Cloud in a Plane Gravitational Wave","authors":"V. Epp,&nbsp;K. Osterin","doi":"10.1007/s10511-024-09821-6","DOIUrl":"10.1007/s10511-024-09821-6","url":null,"abstract":"<p>For the perturbative model of a plane gravitational wave on a flat background of Minkowski space-time, electromagnetic radiation from a charged cloud in the field of a gravitational wave, detected by a remote observer, was found. It is shown that the charge density in the cloud does not change, and the radiation is generated by currents induced by the gravitational wave. The angular distribution of the radiation is obtained. If the refractive index of the cloud medium is greater than unity, Cherenkov-type radiation is generated.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141062303","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":"Magnetic Field Structures of Chemically Peculiar Stars. I. HD57682, HD81009","authors":"Yu. V. Glagolevskij","doi":"10.1007/s10511-024-09813-6","DOIUrl":"10.1007/s10511-024-09813-6","url":null,"abstract":"<p>Based on published data on the magnitudes of the magnetic field, models of the magnetic field of magnetic stars of various types of peculiarity HD57682 and HD81009 are constructed and the parameters of their magnetic fields are obtained. In HD57682, like other hot objects, differences are observed in the physical conditions in the region of the magnetic equators and in the regions near the magnetic poles, which have not yet been interpreted. In terms of its properties, the star HD81009 is a typical representative of magnetic stars of the SrCrEu-type, except for is binary character.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140965767","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":"Структуры магнитного поля химически пекулярных звезд. II.HD 98088, HD182180, HD221218, HD318107","authors":"Ю. В. Глаголевский","doi":"10.54503/0002-3051-2024.77.1-41","DOIUrl":"https://doi.org/10.54503/0002-3051-2024.77.1-41","url":null,"abstract":"На основе литературных данных о величинах магнитного поля построены модели магнитного поля нескольких магнитных звезд разных типов пекулярности и получены параметры магнитного поля. Среди горячих объектов обнаружены различия физических условий в области магнитных экваторов и в области близмагнитных полюсов, которые пока не поддаются интерпретации.Based on literature data about the magnetic field values, models of the magnetic\u0000field of several magnetic stars of different types of peculiarity were constructed and\u0000the magnetic field parameters were obtained. Among hot objects, differences in\u0000physical conditions have been discovered in the region of the magnetic equators\u0000and in the region near the magnetic poles, which are not yet amenable to\u0000interpretation","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140732281","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":"Фотометрические и спектральные исследования группы галактических звезд Вольфа-Райе. Ii. WC и WO последовательности","authors":"Л. Н. Кондратьева, Игорь Витальевич Рева, Э.К. Денисюк, С.А. Шомшекова, А. К. Айманова","doi":"10.54503/0002-3051-2024.77.1-13","DOIUrl":"https://doi.org/10.54503/0002-3051-2024.77.1-13","url":null,"abstract":"Photometric and spectral observations of 7 WC and WO stars were carried\u0000out at the FAI in 2021-2022. On the base of observations we obtained estimates\u0000of the brightness of objects in the BVRc filters and absolute fluxes of radiation\u0000in the emission lines. Changes in brightness within 0m.1 - 0m.15 were detected in\u0000WR 121. Changes in the emission-line fluxes were detected in the spectra of\u0000several objects: WR 4, WR 5 and WR 121.","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140732405","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":"Physical Acceptability Of The Renyi Holographic Dark Energy Model Under The Hubble's Cutoff In F(T, B) Gravity","authors":"N. T. Katre, K. Pawar, A. Dabre","doi":"10.54503/0002-3051-2024.77.1-105","DOIUrl":"https://doi.org/10.54503/0002-3051-2024.77.1-105","url":null,"abstract":"The paper deals with the investigations of the behaviour and physical acceptability of the spatially homogeneous and isotropic FLRW space-time filled with pressureless matter and Rényi holographic dark energy under the Hubble's IR-cutoff in the framework of f(T, B) gravity. We have calculated some cosmological parameters to study the astrophysical consequences of the constructed model. We discussed their behaviour during the cosmic evolution, in particular, the statefinder and EoS parameters. It is found that the constructed Rényi holographic dark energy model travels from Phantom, CDM , and lastly enters & remains in Quintessence dark energy era with the increase in redshift.\u0000Статья посвящена исследованию поведения и физической приемлемости пространственно однородного и изотропного пространства-времени FLRW, заполненного материей без давления и голографической темной энергией Реньи при ИК-пороге Хаббла в рамках гравитации f T, B. \u0000Рассчитаны некоторые космологические параметры для изучения астрофизических следствий построенной модели. Обсуждается их поведение в ходе эволюции, в том числе, параметры\u0000определителя состояния и параметры EoS. Обнаружено, что построенная голографическая модель темной энергии Реньи \"путешествует\" из Фантома, CDM и, наконец, входит и остается в эре темной энергии Квинтэссенции с увеличением красного смещения.","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140729615","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":"Потеря массы атмосферы планеты TOI-1442 S","authors":"Е. С. Дмитриенко, И. С. Саванов","doi":"10.54503/0002-3051-2024.77.1-61","DOIUrl":"https://doi.org/10.54503/0002-3051-2024.77.1-61","url":null,"abstract":"Рассмотрены свойства планетной системы TOI-1422, в которой две планеты типа нептун вращаются вокруг малоактивной звезды солнечного типа около 5 млрд лет. Ранее нами был проведен анализ проявлений активности звезды TOI- 1422, найдены указания на существование возможных циклов активности и рассмотрены оценки величины периода Р вращения звезды.\u0000The properties of the TOI-1422 planetary system in which two neptune-type planets orbit around of low-activity solar-type star with the age of about 5 billion years are considered. Earlier we analyzed the activity of the star TOI-1422 and found indications of the existence of possible cycles of activity and considered estimates of the rotation period of the star.","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140730943","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":"Активность звезды TOI-784 и потеря атмосферной массы ее планетой","authors":"И. С. Саванов","doi":"10.54503/0002-3051-2024.77.1-55","DOIUrl":"https://doi.org/10.54503/0002-3051-2024.77.1-55","url":null,"abstract":"","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140729889","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":"The Digitized First Byurakan Survey Database Late-Type Stars Candidates. New Confirmations. II","authors":"K. Gigoyan, K. Gigoyan, A. Sarkissian, M. Meftah, S. Bekki, E. Karapetyan, F. Rahmatullaeva, G. Kostandyan","doi":"10.54503/0002-3051-2024.77.1-69","DOIUrl":"https://doi.org/10.54503/0002-3051-2024.77.1-69","url":null,"abstract":"Three new carbon C stars was confirmed among the sample of the Late-Type Stars candidates, selected on the Digitized First Byurakan Survey (DFBS) spectral plates. The DFBS is the digitized version of the First Byurakan Survey (FBS, or Markarian survey). The FBS was the first systematic survey of the extragalactic sky. This objective-prism survey was carried out in 1965-1980 by B.E.Markarian and his colleagues using the 1 m Schmidt telescope of the Byurakan Astrophysical Observatory and resulted in discovery of 1517 UV-excess (Markarian) galaxies. FBS spectral plates have been used long period to search and study faint LTS (C-type and M-type stars) at high Galactic latitudes. In this work we present Gaia DR3 photometric data, spectra, light curves, distances, high above/below Galactic plane, radial velocities (RV), and other important physical characteristics from the modern astronomical catalogues for three new confirmed DFBS C stars. The confirmation is based on Gaia DR3 BP/RP low-resolution spectral database. In our previous studies of the DFBS plates, these objects were presented as LTS candidates. One of the new confirmed objects is N-type C star, which is a Mira-type variable. Two remaining objects, are early CH-type giants at high Galactic latitudes. Most probably they present binary systems.\u0000Три новые углеродные С звезды были подтверждены среди кандидатов звезд поздних спектральных классов, отобранных на оцифрованных пластинках Первого Бюраканского Обзора (DFBS). DFBS - это оцифрованная версия Первого Бюраканского Обзора (FBS) или Маркаряновского обзора. FBS является первым систематическим внегалактическим обзором. Он был осуществлен Маркаряном и его коллегами в 1965-1980гг. с объективной призмой с использованием 1-м телескопа Шмидта Бюраканской астрофизической обсерватории (БАО) и увенчался открытием 1517 галактик с UV-\u0000избытком, названных галактиками Маркаряна. Пластинки обзора FBS длительное время\u0000использовались для поиска и изучения слабых звезд поздних спектральных типов (LTS, M и С (углеродные)) на высоких галактических широтах. В данной работе мы приводим Gaia DR3 фотометрические данные, спектры, кривые блеска, расстояния, радиальные скорости (RV) и другие \u0000важные физические характеристики из современных астрономических каталогов для трех новых DFBS C звезд. Подтверждение основано на Gaia DR3 BP/RP спектральных базах данных. В наших предыдущих исследованиях эти объекты были представлены как кандидаты в LTS. Oдним из новых \u0000подтвержденных объектов, это C звезда типа N. Два оставшихся объекта являются CH гигантами в высоких галактических широтах. Скорее всего, они представляют двойные системы.","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140728067","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":"Classification Of Flat Spectrum Radio Quasars By Optical Activity Types","authors":"A. Mickaelian, H. Abrahamyan, G. Paronyan, G. Mikayelyan, A. G. Sukiasyan, V. K. Mkrtchyan","doi":"10.54503/0002-3051-2024.77.1-5","DOIUrl":"https://doi.org/10.54503/0002-3051-2024.77.1-5","url":null,"abstract":"We have carried out a spectral classification by the activity types for a subsample of blazars from the BZCAT v.5 Catalogue, namely the Flat Spectrum Radio Quasars (FSRQ) candidates, designated in the catalogue as BZQ subtype objects. The classification is based on the Sloan Digital Sky Survey (SDSS) homogeneous medium-resolution optical spectroscopy and along with the standard BPT-type diagnostic diagrams, we have applied our newly introduced fine classification scheme with subtypes of quasars and considering many more features. Out of 1909 BZQ objects, 618 having SDSS spectra were classified, resulting in 445 broad-line QSOs, 19 narrow-line QSOs, 138 broad-line Seyferts, 8 narrow-line Seyferts, and 2 Emission-line galaxies without a proper classification. We have calculated the absolute magnitudes and luminosities for all objects to distinguish QSOs from Seyferts, as defined by the Catalogue of QSOs and Active Galaxies, -22m.25 separation limit. This way 148 objects changed their BZCAT subtypes between BZQ to BZG, and also 6 BZQ objects to BZU.","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140731472","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}