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Related papers: Consistent Solar Models Including the $^7$Li and $…

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Models of the solar transition region made from lines other than those of helium cannot account for the strength of the helium lines. However, the collisional excitation rates of the helium resonance lines are unusually sensitive to the…

Astrophysics · Physics 2009-11-07 G. R. Smith , C. Jordan

We compute rotating 1D stellar evolution models that include a modified temperature gradient in convection zones and criterion for convective instability inspired by rotating 3D hydrodynamical simulations performed with the MUSIC code. In…

Solar and Stellar Astrophysics · Physics 2021-10-27 Thomas Constantino , Isabelle Baraffe , Thomas Goffrey , Jane Pratt , Thomas Guillet , Dimitar Vlaykov , Louis Amard

Solar oscillations frequencies show a distinct change with solar activity. The changes in frequencies can be used to study the time variation of solar structure. We discuss constraints on the changes in solar structure with time as obtained…

Astrophysics · Physics 2007-05-23 Sarbani Basu

Context. Acoustic waves in the Sun are affected by the atmospheric layers, but this region is often ignored in forward models due to the increase in computational cost. Aims. The purpose of this work is to take into account the solar…

Solar and Stellar Astrophysics · Physics 2025-07-15 Damien Fournier , Janosch Preuss , Thorsten Hohage , Laurent Gizon

Context : On its asteroseismic side, the initial run of CoRoT was partly devoted to the solar like star HD49933.The eigenmodes of this F dwarf have been observed with unprecedented accuracy. Aims : We investigate quantitatively the impact…

Solar and Stellar Astrophysics · Physics 2015-05-13 L. Piau , S. Turck-Chieze , V. Duez , R. F. Stein

We present the first constraints on the cross-correlation power spectrum of HeII ($^{+}{\rm He}^3$) signal strength using the redshifted 8.67GHz hyperfine transition between $z=2.9$ and $z=4.1$ and with interferometric data obtained from…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-22 Cathryn M. Trott , Randall B. Wayth

Local helioseismology has opened new frontiers in our quest for understanding of the internal dynamics and dynamo on the Sun. Local helioseismology reconstructs subsurface structures and flows by extracting coherent signals of acoustic…

Solar and Stellar Astrophysics · Physics 2016-07-20 Alexander G. Kosovichev , Junwei Zhao

One-dimensional, semi-empirical models of the solar atmosphere are widely employed in numerous contexts within solar physics, ranging from the determination of element abundances and atomic parameters to studies of the solar irradiance and…

Solar and Stellar Astrophysics · Physics 2024-04-11 J. M. Borrero , I. Milic , A. Pastor Yabar , A. J. Kaithakkal , J. de la Cruz Rodriguez

The material ejected from a binary neutron star merger produces "kilonova," a radioactively powered emission at ultraviolet, optical, and infrared wavelengths. The early-phase spectra of the kilonova AT2017gfo, following the gravitational…

High Energy Astrophysical Phenomena · Physics 2026-04-08 Koya Chiba , Masaomi Tanaka , Shinya Wanajo , Sho Fujibayashi , Kyohei Kawaguchi , Kenta Hotokezaka

Traditionally, fast solar wind is considered to originate in solar source regions that are continuously open to the heliosphere and slow wind originates in regions that are intermittently open to it. In fast wind, the gradient of the solar…

Space Physics · Physics 2025-12-29 B. L. Alterman , R. D'Amicis

In helioseismology, there is a well-known offset between observed and computed oscillation frequencies. This offset is known to arise from improper modeling of the near-surface layers of the Sun, and a similar effect must occur for models…

Astrophysics · Physics 2009-11-13 Hans Kjeldsen , Timothy R. Bedding , Joergen Christensen-Dalsgaard

We construct helium (He) star models with optically thick winds and compare them with the properties of Galactic Wolf-Rayet (WR) stars. Hydrostatic He-core solutions are connected smoothly to trans-sonic wind solutions that satisfy the…

Solar and Stellar Astrophysics · Physics 2018-01-31 Daisuke Nakauchi , Hideyuki Saio

We investigate the effect of helium abundance and $\alpha$-element enhancement on the properties of convection in envelopes of solar-like main-sequence stars stars using a grid of 3D radiation hydrodynamic simulations. Helium abundance…

Solar and Stellar Astrophysics · Physics 2015-06-17 Joel D. Tanner , Sarbani Basu , Pierre Demarque

Luminosity, which is the total amount of radiant energy emitted by an object, is one of the most critical quantities in astrophysics for characterizing stars. Equally important is the temporal evolution of a star's luminosity because of its…

Solar and Stellar Astrophysics · Physics 2022-06-20 L. E. A. Vieira , G. Kopp , T. Dudok de Wit , L. A. da Silva , F. Carlesso , A. Barbosa , A. Muralikrishna , R. Santos

Based on radiation hydrodynamics modeling of stellar convection zones, a diffusion scheme has been devised describing the downward penetration of convective motions beyond the Schwarzschild boundary (overshoot) into the radiative interior.…

Astrophysics · Physics 2009-10-30 T. Bloecker , H. Holweger , B. Freytag , F. Herwig , H. -G. Ludwig , M. Steffen

Cosmological models can be constrained by determining primordial abundances. Accurate predictions of the He I spectrum are needed to determine the primordial helium abundance to a precision of $< 1$% in order to constrain Big Bang…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-21 F. Guzmán , N. R. Badnell , R. J. R. Williams , P. A. M. van Hoof , M. Chatzikos , G. J. Ferland

The experimental uncertainties in G between different experiments have important implications for helioseismology. We show that these uncertainties for the standard solar model lead to a range in the value of the square of the sound speed…

Astrophysics · Physics 2009-09-25 Ilidio Lopes , Joseph Silk

The stratification near the base of the Sun's convective envelope is governed by processes of convective overshooting and element diffusion, and the region is widely believed to play a key role in the solar dynamo. The stratification in…

Solar and Stellar Astrophysics · Physics 2015-05-27 Joergen Christensen-Dalsgaard , Mario J. P. F. G. Monteiro , Matthias Rempel , Michael J. Thompson

The behavior of lithium (Li) in Population I main sequence stars challenges standard stellar theory. Two phenomena stand out: the solar Li problem which extends to Li depletion in solar analogs and the Li dip observed in mid-F stars within…

Solar and Stellar Astrophysics · Physics 2025-08-28 Xuefeng Li , Jianrong Shi , Yan Li , Hongliang Yan , Jinghua Zhang

We present our results concerning a systematical analysis of helioseismic implications on solar structure and neutrino production. We find Y$_{ph}=0.238-0.259$, $R_b/R_\odot=0.708-0.714$ and $\rho_b=(0.185-0.199)$ gr/cm$^3$. In the interval…

Astrophysics · Physics 2015-06-24 V. Castellani , S. Degl'Innocenti , W. A. Dziembowski , G. Fiorentini , B. Ricci
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