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We present a model for the lower overshoot layer of the Sun, based on the realistic solar stratification, without the use of a "mixing-length" parameter, by solving the system of Reynolds momentum equations using the closure formalism of…

天体物理学 · 物理学 2009-11-10 D. Marik , K. petrovay

Doppler shifts of the Fe I spectral line at lambda5250 Angstroms from the full solar disk obtained over the period 1986 to 2009 are analyzed to determine the circulation velocity of the solar surface along meridional planes. Simultaneous…

太阳与恒星天体物理 · 物理学 2015-05-20 Roger K. Ulrich

We present two-dimensional numerical simulations of convection and waves in a 7 solar mass star across stellar ages ranging from zero age to terminal-age-main-sequence. We show that waves efficiently transport angular momentum across the…

太阳与恒星天体物理 · 物理学 2025-04-08 Tamara Marie Rogers , Rathish Previn Ratnasingam

The Solar Wind Electrons Alphas and Protons experiment on the Parker Solar Probe (PSP) mission measures the three-dimensional electron velocity distribution function. We derive the parameters of the core, halo, and strahl populations…

We re-estimate the peculiar velocity of the Sun with respect to the local standard of rest using a sample of local stars within 600 pc of the Sun, selected from the LAMOST Spectroscopic Survey of the Galactic Anti-centre (LSS-GAC). The…

星系天体物理 · 物理学 2015-06-23 Yang Huang , Xiaowei Liu , Haibo Yuan , Maosheng Xiang , Zhiying Huo , Bingqiu Chen , Yong Zhang , Yonghui Hou

New data on the membership of the Local Group, in conjunction with new and improved radial velocity data, are used to refine the derivation of the motion of the Sun relative to the Local Group (hereafter LG). The Sun is found to be moving…

天体物理学 · 物理学 2009-10-31 Stephane Courteau , Sidney van den Bergh

Quasi-periodic disturbances have been observed in the outer solar atmosphere for many years now. Although first interpreted as upflows (Schrijver et al. (1999)), they have been widely regarded as slow magnetoacoustic waves, due to observed…

太阳与恒星天体物理 · 物理学 2015-06-05 G. Kiddie , I. De Moortel , G. Del Zanna , S. W. McIntosh , I. Whittaker

It is of great importance to track the solar wind back to its photospheric source region and identify the related current sheets; this will provide key information for investigating the origin and predictions of the solar wind. We report a…

太阳与恒星天体物理 · 物理学 2014-03-05 C. Huang , Y. Y. Yan , G. Li , Y. Y. Deng , B. L. Tan

Magnetoconvection at the solar surface governs the dynamics in the upper solar atmosphere and sustains the heliosphere. Properties of this fundamental process are poorly described near the solar poles. Here we report the first…

Understanding the global rotational profile of the solar atmosphere and its variation is fundamental to uncovering a comprehensive understanding of the dynamics of the solar magnetic field and the extent of coupling between different layers…

Long-term variations of solar differential rotation and sunspot activity are investigated through re-analyzing the data on parameters of the differential rotation law obtained by Makarov, Tlatov, and Callebaut (1997), Javaraiah, Bertello,…

太阳与恒星天体物理 · 物理学 2015-06-05 K. J. Li , W. Feng , X. J. Shi , J. L. Xie , P. X. Gao , H. F. Liang

As fundamental parameters of the Sun, the Alfv\'en radius and angular momentum loss determine how the solar wind changes from sub-Alfv\'enic to super-Alfv\'enic and how the Sun spins down. We present an approach to determining the solar…

太阳与恒星天体物理 · 物理学 2021-06-23 Ying D. Liu , Chong Chen , Michael L. Stevens , Mingzhe Liu

The Sun's internal rotation {\Omega}(r,{\Theta}) has previously been measured using helioseismology techniques and found to be a complex function of co-latitude, {\theta}, and radius, r. From helioseismology and observations of apparently…

太阳与恒星天体物理 · 物理学 2017-02-08 Ian Cunnyngham , Marcelo Emilio , Jeff Kuhn , Isabelle Scholl , Rock Bush

Orbit spin coupling is proposed as an alternative to planetary tidal models for the excitation of solar variability as a function of time. Momentum sourced from the orbital angular momenta of solar system bodies is deposited within the…

太阳与恒星天体物理 · 物理学 2023-09-26 James H Shirley

Context. Solar active regions are known to have jets. These jets are associated with heating and the release of particles into the solar wind. Aim. Our aim is to understand the spatial distribution of coronal jets within active regions to…

太阳与恒星天体物理 · 物理学 2022-09-07 Jonas Odermatt , Krzysztof Barczynski , Louise K. Harra , Conrad Schwanitz , Säm Krucker

Solar activity is studied using a cluster analysis of the time-fluctuations of sunspot number. In the historic period (1850-1932) the cluster exponent was approximately equal to 0.37 (strong clustering) for the high activity components of…

太阳与恒星天体物理 · 物理学 2009-08-03 A. Bershadskii

As a large-scale motion on the Sun, the meridional flow plays an important role in determining magnetic structure and strength and solar cycle. However, the meridional flow near the solar poles is still unclear. The Hinode observations show…

太阳与恒星天体物理 · 物理学 2024-07-29 Shuhong Yang , Jie Jiang , Zifan Wang , Yijun Hou , Chunlan Jin , Qiao Song , Yukun Luo , Ting Li , Jun Zhang , Yuzong Zhang , Guiping Zhou , Yuanyong Deng , Jingxiu Wang

Sun-like stars shed angular momentum due to the presence of magnetised stellar winds. Magnetohydrodynamic models have been successful in exploring the dependence of this "wind-braking torque" on various stellar properties, however the…

太阳与恒星天体物理 · 物理学 2023-05-31 Adam J. Finley , Allan Sacha Brun

We analyzed the sunspot-group daily data that were reported by Greenwich Photoheliogrphic Results (GPR) during the period 1874-1976 and Debrecen Photoheliographic Data (DPD) during the period 1977-2017. We determined the equatorial rotation…

太阳与恒星天体物理 · 物理学 2020-12-04 J. Javaraiah

We investigate periodicities in mean heliographic latitudes of sunspot groups, called active latitudes, for the last six complete solar cycles (1945-2008). For this purpose, the Multi Taper Method and Morlet Wavelet analysis methods were…

太阳与恒星天体物理 · 物理学 2023-01-06 A. Kilcik , V. Yurchyshyn , F. Clette , A. Ozguc , J. -P. Rozelot