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Related papers: Calibrating the Mixing Length Parameter for a Red …

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We show that contrary to what is expected from 1D stationary model atmospheres, 3D hydrodynamical modeling predicts a considerable influence of convection on the spectral properties of late-type giants. This is due to the fact that…

Astrophysics · Physics 2009-11-11 A. Kucinskas , H. -G. Ludwig , P. H. Hauschildt

We performed 3D hydrodynamic simulations of the inner $\approx 50\%$ radial extent of a $25\ \mathrm{M_\odot}$ star in the early phase of the main sequence and investigate core convection and internal gravity waves in the core-envelope…

Solar and Stellar Astrophysics · Physics 2023-07-21 Falk Herwig , Paul R. Woodward , Huaqing Mao , William R. Thompson , Pavel Denissenkov , Josh Lau , Simon Blouin , Robert Andrassy , Adam Paul

Asteroseismology is a powerful tool to measure the fundamental properties of stars and probe their interiors. This is particularly efficient for red giants because their modes are well detectable and give information on their deep layers.…

Solar and Stellar Astrophysics · Physics 2017-12-05 M. Benbakoura , P. Gaulme , J. McKeever , P. G. Beck , J. Jackiewicz , R. A. Garcia

We perform a calibration of the mixing length parameter at the bottom boundary of the convection zone for helium-dominated atmospheres of white dwarfs. This calibration is based on a grid of 3D DB (pure-helium) and DBA (helium-dominated…

Solar and Stellar Astrophysics · Physics 2019-09-25 Cukanovaite E. , P. -E. Tremblay , B. Freytag , H. -G. Ludwig , G. Fontaine , P. Brassard , O. Toloza , D. Koester

In this paper, four sets of evolutionary models are computed with different values of the mixing length parameter $\alpha_{\rm p}$ and the overshooting parameter $\delta_{\rm ov}$. The properties of the convective cores and the convective…

Solar and Stellar Astrophysics · Physics 2015-05-14 Jin Jie , Chunhua Zhu , Guoliang Lv

We present new synthetic broad-band photometric colors for late-type giants based on synthetic spectra calculated with the PHOENIX model atmosphere code. The grid covers effective temperatures T_eff=3000...5000K, gravities log…

We aim to describe the oscillation power excess observed in Kepler red giants, and to investigate empirical scaling relations governing these parameters. From these scalings relations, we derive new physical properties of red giant…

The physical parameters of the retired A star HD 185351 were analysed in great detail by Johnson et al. (2014) using interferometry, spectroscopy and asteroseismology. Results from all independent methods are consistent with HD 185351…

Linear damping rates of radial oscillation modes in selected $Kepler$ stars are estimated with the help of a nonadiabatic stability analysis. The convective fluxes are obtained from a nonlocal, time-dependent convection model. The…

Solar and Stellar Astrophysics · Physics 2017-11-08 Günter Houdek

We present the atmospheric structure and the fundamental parameters of three red supergiants, increasing the sample of RSGs observed by near-infrared spectro-interferometry. Additionally, we test possible mechanisms that may explain the…

Solar and Stellar Astrophysics · Physics 2015-02-25 B. Arroyo-Torres , M. Wittkowski , A. Chiavassa , M. Scholz , B. Freytag , J. M. Marcaide , P. H. Hauschildt , P. R. Wood , F. J. Abellan

Main sequence, solar-like stars (M < 1.5 Msun) have outer convective envelopes that are sufficiently thick to affect significantly their overall structure. The radii of these stars, in particular, are sensitive to the details of…

Solar and Stellar Astrophysics · Physics 2018-12-26 F. Spada , P. Demarque , S. Basu , J. D. Tanner

The CoRoT mission has provided thousands of red-giant light curves. The analysis of their solar-like oscillations allows us to characterize their stellar properties. Up to now, the global seismic parameters of the pressure modes remain…

We present the constraints on the cosmological parameters obtained with the $E_{\rm peak}$--$E_{\gamma}$ correlation found with the most recent sample of 19 GRBs with spectroscopically measured redshift and well determined prompt emission…

Astrophysics · Physics 2009-11-11 G. Ghirlanda , G. Ghisellini , C. Firmani , L. Nava , F. Tavecchio , D. Lazzati

Fingering (thermohaline) convection has been invoked for several years as a possible extra-mixing which could occur in Red Giant stars due to the modification of the chemical composition induced by nuclear reactions in the hydrogen burning…

Solar and Stellar Astrophysics · Physics 2014-10-22 F. C. Wachlin , S. Vauclair , L. G. Althaus

We study the nucleosynthesis and the induced mixing during the merging of massive stars inside a common envelope. The systems of interest are close binaries, initially consisting of a massive red supergiant and a main-sequence companion of…

Astrophysics · Physics 2009-11-07 N. Ivanova , Ph. Podsiadlowski

Although not predicted by standard stellar evolution, the surface abundance of light elements, such as lithium (Li), carbon, and nitrogen, changes during the red giant branch (RGB) as a result of extra-mixing. This is associated usually…

Solar and Stellar Astrophysics · Physics 2023-02-08 Claudia Aguilera-Gómez , Matías I. Jones , Julio Chanamé

This paper reports estimated stellar parameters of 1,153 Kepler red giant branch stars determined with asteroseismic modeling. We use radial-mode oscillation frequencies, gravity-mode period spacings, Gaia luminosities, and spectroscopic…

Solar and Stellar Astrophysics · Physics 2023-07-10 Yingxiang Wang , Tanda Li , Shaolan Bi , Timothy R. Bedding , Yaguang Li

The internal structures and properties of oscillating red-giant stars can be accurately inferred through their global oscillation modes (asteroseismology). Based on 1460 days of Kepler observations we perform a thorough asteroseismic study…

We report for the first time a parametric fit to the pattern of the \ell = 1 mixed modes in red giants, which is a powerful tool to identify gravity-dominated mixed modes. With these modes, which share the characteristics of pressure and…

More than 1000 red giants have been observed by NASA/Kepler mission during a nearly continuous period of ~ 13 months. The resulting high-frequency resolution (< 0.03 muHz) allows us to study the granulation parameters of these stars. The…

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