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Related papers: The Stagger-grid - A Grid of 3D Stellar Atmosphere…

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We present the Stagger-grid, a comprehensive grid of time-dependent, 3D hydrodynamic model atmospheres for late-type stars with realistic treatment of radiative transfer, covering a wide range in stellar parameters. This grid of 3D models…

Solar and Stellar Astrophysics · Physics 2015-06-15 Z. Magic , R. Collet , M. Asplund , R. Trampedach , W. Hayek , A. Chiavassa , R. F. Stein , Å. Nordlund

In this contribution, we present the StaggerGrid, a collaborative project for the construction of a comprehensive grid of time-dependent, three-dimensional (3D), hydrodynamic model atmospheres of solar- and late-type stars with different…

Solar and Stellar Astrophysics · Physics 2015-05-30 Remo Collet , Zazralt Magic , Martin Asplund

Present grids of stellar atmosphere models are the workhorses in interpreting stellar observations, and determining their fundamental parameters. These models rely on greatly simplified models of convection, however, lending less predictive…

Solar and Stellar Astrophysics · Physics 2015-06-15 Regner Trampedach , Martin Asplund , Remo Collet , Åke Nordlund , Robert F. Stein

Context: Traditional one-dimensional (1D) hydrostatic model atmospheres introduce systematic modelling errors into spectroscopic analyses of FGK-type stars. Aims: We present an updated version of the STAGGER-grid of 3D model atmospheres,…

We study the implications of averaging methods with different reference depth scales for 3D hydrodynamical model atmospheres computed with the Stagger-code. The temporally and spatially averaged (hereafter denoted as <3D>) models are…

Solar and Stellar Astrophysics · Physics 2015-06-16 Zazralt Magic , Remo Collet , Wolfgang Hayek , Martin Asplund

In the surface layers of late-type stars, stellar convection is manifested with its typical granulation pattern due to the presence of convective motions. The resulting photospheric up- and downflows leave imprints in the observed spectral…

Solar and Stellar Astrophysics · Physics 2014-05-30 Zazralt Magic , Martin Asplund

Context. The surface structures and dynamics of cool stars are characterized by the presence of convective motions and turbulent flows which shape the emergent spectrum. Aims. We used realistic three-dimensional radiative hydrodynamical…

Solar and Stellar Astrophysics · Physics 2018-03-14 A. Chiavassa , L. Casagrande , R. Collet , Z. Magic , L. Bigot , F. Thevenin , M. Asplund

Grids of stellar atmosphere models and associated synthetic spectra are numerical products which have a large impact in astronomy due to their ubiquitous application in the interpretation of radiation from individual stars and stellar…

Solar and Stellar Astrophysics · Physics 2009-09-02 H. -G. Ludwig , E. Caffau , M. Steffen , B. Freytag , P. Bonifacio , A. Kucinskas

We investigate the relation between 1D atmosphere models that rely on the mixing length theory and models based on full 3D radiative hydrodynamic (RHD) calculations to describe convection in the envelopes of late-type stars. The adiabatic…

Solar and Stellar Astrophysics · Physics 2014-12-24 Zazralt Magic , Achim Weiss , Martin Asplund

We compute the emergent stellar spectra from the UV to far infrared for different viewing angles using realistic 3D model atmospheres for a large range in stellar parameters to predict the stellar limb darkening. We have computed full 3D…

Solar and Stellar Astrophysics · Physics 2014-12-24 Zazralt Magic , Andrea Chiavassa , Remo Collet , Martin Asplund

I describe recent progress in terms of 3D hydrodynamical model atmospheres and 3D line formation and their applications to stellar abundance analyses of late-type stars. Such 3D studies remove the free parameters inherent in classical 1D…

Astrophysics · Physics 2007-05-23 Martin Asplund

Stellar structure calculations are able to predict precisely the properties of stars during their evolution. However, convection is still modelled by the mixing length theory; therefore, the upper boundary conditions near the optical…

Solar and Stellar Astrophysics · Physics 2016-02-03 Zazralt Magic

Stellar evolution codes play a major role in present-day astrophysics, yet they share common issues. In this work we seek to remedy some of those by the use of results from realistic and highly detailed 3D hydrodynamical simulations of…

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

Late type giants (RGB/AGB stars) will be important tracers of the Galactic morphology and evolution in the framework of Gaia, as they are intrinsically bright and thus can probe distant stellar populations or those obscured by interstellar…

During the recent years significant progress has been made in the modeling of red giant atmospheres with the aid of 3D hydrodynamical model atmosphere codes. In this contribution we provide an overview of selected results obtained in this…

Solar and Stellar Astrophysics · Physics 2013-05-16 A. Kucinskas , H. -G. Ludwig , M. Steffen , V. Dobrovolskas , J. Klevas , D. Prakapavicius , E. Caffau , P. Bonifacio

Stellar evolution codes play a major role in present-day astrophysics, yet they share common simplifications related to the outer layers of stars. We seek to improve on this by the use of results from realistic and highly detailed 3D…

We compare current 1D and multi-dimensional atmosphere modelling approaches for massive stars to understand their strengths and shortcomings. We calculate averaged stratifications from selected 2D calculations for O stars -- corresponding…

Three-dimensional radiation-hydrodynamics (3D RHD) simulations of stellar surface convection provide valuable insights into many problems in solar and stellar physics. However, almost all 3D near-surface convection simulations to date are…

Solar and Stellar Astrophysics · Physics 2023-09-13 Yixiao Zhou , Anish M. Amarsi , Victor Aguirre Børsen-Koch , Klara G. Karlsmose , Remo Collet , Thomas Nordlander

Recently 3D hydrodynamical simulations of stellar surface convection have become feasible thanks to advances in computer technology and efficient numerical algorithms. Available observational diagnostics indicate that these models are…

Astrophysics · Physics 2007-05-23 Martin Asplund , Remo Collet
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