Astronomy Letters-A Journal of Astronomy and Space Astrophysics最新文献

Generation of Energetic Electrons in the Alfvén Wings of Ganymede and Europa 在木卫三和木卫二的alfvsamn翼中高能电子的产生

IF 0.9 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-09-14 DOI: 10.1134/S1063773726700325

V. V. Zaitsev, V. E. Shaposhnikov, T. V. Simonova

{"title":"Generation of Energetic Electrons in the Alfvén Wings of Ganymede and Europa","authors":"V. V. Zaitsev, V. E. Shaposhnikov, T. V. Simonova","doi":"10.1134/S1063773726700325","DOIUrl":"10.1134/S1063773726700325","url":null,"abstract":"This paper is devoted to investigating the acceleration of the particles that are produced when the incident flow of the Jovian magnetosphere interacts with the atmospheres of Ganymede and Europa with the goal of analyzing the origin of the energetic particles that provide the ultraviolet and decameter emissions from the feet of the magnetic flux tubes of these satellites. We consider the mechanism of particle acceleration by Alfvén waves. We draw attention to the possible realization of a nonlinear stage of evolution of the Alfvén waves that transport the electric current in the Alfvén wings of Ganymede and Europa. We show a significant influence of nonlinearity on the proper estimate of the efficiency of the Alfvén acceleration mechanism and its applicability for explaining the observed ultraviolet fluxes from the feet of the magnetic flux tubes of Ganymede and Europa. The acceleration by linear inertial Alfvén waves is much less efficient and cannot provide the necessary energies of fast electrons for the generation of the observed emission triggered by these Jovian satellites.","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"52 4","pages":"203 - 209"},"PeriodicalIF":0.9,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148962186","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

Study of the New Cataclysmic Variable Candidate SRGe J020254.8(boldsymbol{+})403705 新突变候选变量SRGe J020254.8 (boldsymbol{+}) 403705的研究

IF 0.9 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-09-14 DOI: 10.1134/S1063773726700283

P. D. Efremova, I. F. Bikmaev, A. S. Sklyanov, I. M. Khamitov, M. V. Suslikov, M. A. Gorbachev, E. N. Irtuganov, R. I. Gumerov, N. A. Sakhibullin, M. R. Gilfanov, R. A. Sunyaev, P. S. Medvedev

{"title":"Study of the New Cataclysmic Variable Candidate SRGe J020254.8(boldsymbol{+})403705","authors":"P. D. Efremova, I. F. Bikmaev, A. S. Sklyanov, I. M. Khamitov, M. V. Suslikov, M. A. Gorbachev, E. N. Irtuganov, R. I. Gumerov, N. A. Sakhibullin, M. R. Gilfanov, R. A. Sunyaev, P. S. Medvedev","doi":"10.1134/S1063773726700283","DOIUrl":"10.1134/S1063773726700283","url":null,"abstract":"We present the results of our optical and spectroscopic observations of the X-ray source SRGe J020254.8(+)403705 carried out in 2023–2025 with the 1.5-m Russian–Turkish telescope (RTT-150). Our photometric data analysis has revealed two periodicities: (54.2563pm 0.0014) and (147.7828pm 0.0043) min. The short period is reliably detected both from our photometry and from the variability in spectral lines and is interpreted as the white-dwarf spin period. The long period has been found only from the photometric variability and may be associated with the orbital motion of the system. The optical spectra of the source contain a flat continuum with intense emission lines of hydrogen and neutral and ionized helium, including the He II (lambda 4686) line. The presence of an inverted Balmer decrement, the variability of the line equivalent widths and FWHMs with the white-dwarf spin period, and their antiphase variations point to a possible contribution of magnetically controlled accretion to the emission from the system. The SRG/eROSITA and Swift/XRT spectra of SRGe J020254.8(+)403705 in the energy range 0.3–10 keV are well described by the model of a hot optically thin plasma with a temperature (kTsim 30) keV and luminosities (L_{textrm{x}}approx 0.5times 10^{33}) and ({approx}1times 10^{33}) erg s({}^{-1}), respectively, consistent with accretion onto a magnetic white dwarf. The corresponding estimates of the accretion rates are (dot{M}approx 0.5times 10^{-10}) and ({approx}1times 10^{-10};M_{odot}) yr({}^{-1}). According to our results, SRGe J020254.8(+)403705 is classified as an intermediate polar.","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"52 4","pages":"145 - 161"},"PeriodicalIF":0.9,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148962189","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

Shapes of 11-Year Solar Cycles: A Nonparametric Approach 11年太阳周期的形状：一种非参数方法

IF 0.9 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-09-14 DOI: 10.1134/S1063773726700313

Yu. A. Nagovitsyn, S. N. Fedoseeva

引用次数: 0

Photometric and Spectral Variability of the Candidate Post-AGB Star IRAS 07506-0345 agb后候选恒星IRAS 07506-0345的光度和光谱变异性

IF 0.9 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-09-14 DOI: 10.1134/S1063773726700301

N. P. Ikonnikova, M. A. Burlak, A. V. Dodin

引用次数: 0

Photometric and Physical Properties of CW Tau and Other Stars in Its Vicinity 连续波Tau及其附近其他恒星的光度和物理性质

IF 0.9 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-09-14 DOI: 10.1134/S1063773726700295

K. N. Grankin

{"title":"Photometric and Physical Properties of CW Tau and Other Stars in Its Vicinity","authors":"K. N. Grankin","doi":"10.1134/S1063773726700295","DOIUrl":"10.1134/S1063773726700295","url":null,"abstract":"The photometric (VR_{c}I_{c}) observations of CW Tau, V773 Tau, FM Tau, FO Tau, CIDA 2, and LkCa 4 in December 2024–November 2025 are described and analyzed. The brightnesses and colors of two potential comparison stars are determined. The rotational modulation of the brightness in LkCa 4 and V773 Tau is confirmed. It is shown that the age of the components FO Tau A and FO Tau B is ({sim}2.5) Myr, while the age of V773 Tau Aa and V773 Tau Ab is ({sim}2.3) and ({sim}3.7) Myr, respectively. The problems of determining the brightnesses and colors of the quiet photosphere in young stars exhibiting a significant photometric variability due to the presence of extended cool photospheric spots, variable circumstellar extinction, and unstable accretion are discussed. The basic physical parameters of the single stars in our sample are determined and discussed. It is noted that the age of FM Tau (9.7–11.2 Myr) determined by taking into account the photometric data and the dynamical mass differs significantly from the mean age of the remaining stars in our sample (2.76 Myr).","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"52 4","pages":"178 - 202"},"PeriodicalIF":0.9,"publicationDate":"2026-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148962199","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

Influence of Circumbinary Disks on the X-ray Variability of Binary Systems 环双星盘对双星x射线变异性的影响

IF 0.9 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-08-28 DOI: 10.1134/S1063773726700246

A. R. Emelyanova

引用次数: 0

SS433: New Results of Optical Studies 光学研究的新结果

IF 0.9 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-08-28 DOI: 10.1134/S1063773726700234

A. M. Cherepashchuk

{"title":"SS433: New Results of Optical Studies","authors":"A. M. Cherepashchuk","doi":"10.1134/S1063773726700234","DOIUrl":"10.1134/S1063773726700234","url":null,"abstract":"The 30-year spectroscopic and photometric monitoring of SS433 performed at the Sternberg Astronomical Institute in combination with all of the published data since 1978 have yielded a number of results that shed light on the nature of this unique microquasar. 1. The parameters of the kinematic model for SS433 (with the exception of some jumps in the precessional phase), on average, are stable over 45 years, arguing for the model of a slaved accretion disk tracking the precession of the rotation axis of the optical star. 2. The orbit of SS433 is elliptical with an eccentricity (e=0.05pm 0.01). This supports the model of a slaved accretion disk. 3. A secular evolutionary increase in the orbital period of SS433 at a rate (dot{P}_{textrm{orb}}=(1.14pm 0.25)times 10^{-7}) s s({}^{-1}) has been discovered. Hence it follows that the relativistic object in SS433 is a black hole with a mass of more than 8 (M_{odot}). 4. It follows from the increase in the orbital period of SS433 that the semimajor axis of this binary system increases with time, preventing the formation of a common envelope in the binary. Therefore, SS433 evolves as a semidetached binary system—a powerful wind from the supercritical accretion disk stabilizes the binary system. This paper has been written using the materials of the report presented by us at the Conference ‘‘High-Energy Astrophysics Today and Tomorrow—2025’’ and is based on our more detailed paper published in UFN (Cherepashchuk et al. 2025).","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"52 3","pages":"107 - 118"},"PeriodicalIF":0.9,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823096","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

Slowdown of Positrons Produced when Hard Background Gamma-Ray Photons Interact with Soft Background Photons 硬背景伽玛射线光子与软背景光子相互作用时产生的正电子减速

IF 0.9 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-08-28 DOI: 10.1134/S1063773726700271

A. N. Popov, D. P. Barsukov, A. V. Ivanchik, S. V. Bobabshev

引用次数: 0

Modeling the Gravitational Wave Signal from the X-ray Pulsar Her X-1 x射线脉冲星Her X-1的引力波信号建模

IF 0.9 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-08-28 DOI: 10.1134/S106377372670026X

I. D. Markozov, G. K. Pimenov, A. A. Mushtukov

引用次数: 0

On Radio Pulsars with Magnetic Fields (boldsymbol{10^{9}{-}10^{10}}) G 关于具有磁场的射电脉冲星(boldsymbol{10^{9}{-}10^{10}}) G

IF 0.9 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-08-28 DOI: 10.1134/S1063773726700258

I. F. Malov, M. A. Timirkeeva

{"title":"On Radio Pulsars with Magnetic Fields (boldsymbol{10^{9}{-}10^{10}}) G","authors":"I. F. Malov, M. A. Timirkeeva","doi":"10.1134/S1063773726700258","DOIUrl":"10.1134/S1063773726700258","url":null,"abstract":"We have analyzed a number of features in radio pulsars with surface magnetic fields in the range (10^{9}{-}10^{10}) G. In the distribution of magnetic fields for the pulsars from the ATNF catalog the sample under study corresponds to the minimum between the millisecond and normal pulsars. We provide arguments for the assumption that the central neutron stars in this sample are in binary systems and continue to spin up through the accretion of matter outflowing from the companion. More than (70%) of the pulsars under study are actually members of binary systems. They must be younger than the millisecond pulsars that have reached their minimum spin period. Indeed, their mean characteristic age is a factor of 2.5 shorter than that of millisecond pulsars, while their kinematic age, which is much closer to the real one, is several million years. In this time, such pulsars could not go far from the Galactic disk, where they were born and evolved. Indeed, they are concentrated near the disk, while their height (z) above the Galactic plane does not exceed several tens of parsecs for most of the pulsars in the sample under study.","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"52 3","pages":"140 - 144"},"PeriodicalIF":0.9,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148823093","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