Related papers: Korg: fitting, model atmosphere interpolation, and…
We present Korg, a new package for 1D LTE (local thermodynamic equilibrium) spectral synthesis of FGK stars, which computes theoretical spectra from the near-ultraviolet to the near-infrared, and implements both plane-parallel and spherical…
We performed extensive tests of the accuracy of atmospheric parameter determination for FGK stars based on the spectrum fitting procedure Spectroscopy Made Easy (SME). Our stellar sample consists of 13 objects, including the Sun, in the…
Mg is often traced in late-type stars using lines of neutral magnesium, which is expected to be subject to departures from LTE. The astrophysical importance of Mg as well as its relative simplicity from an atomic physics point of view,…
Accurate spectroscopic lithium abundances are essential in addressing a variety of open questions, such as the origin of a uniform lithium content in the atmospheres of metal-poor stars (Spite plateau) or the existence of a correlation…
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,…
In an effort to estimate the largely unknown effects of photospheric temperature fluctuations on spectroscopic abundance determinations, we have studied the problem of LTE line formation in the inhomogeneous solar photosphere based on…
Planetary studies demand precise and accurate stellar parameters as input to infer the planetary properties. Different methods often provide different results that could lead to biases in the planetary parameters. In this work, we present a…
Multiple codes are available to derive atmospheric parameters and individual chemical abundances from high-resolution spectra of AFGKM stars. Almost all spectroscopists have their own preferences regarding which code and method to use. But…
Spectra of late-type stars are usually analyzed with static model atmospheres in local thermodynamic equilibrium (LTE) and a homogeneous plane-parallel or spherically symmetric geometry. The energy balance requires particular attention, as…
We present a new stellar atmosphere interpolator which we will use to compute stellar population models based on empirical and/or synthetic spectra. We combined observed and synthetic stellar spectra in order to achieve more or less uniform…
Given the widespread availability of grids of models for stellar atmospheres, it is necessary to recover intermediate atmospheric models by means of accurate techniques that go beyond simple linear interpolation and capture the intricacies…
Very young (t $\lesssim$ 10 Myrs) stars possess strong magnetic fields that channel ionized gas from the interiors of their circumstellar discs to the surface of the star. Upon impacting the stellar surface, the shocked gas recombines and…
We present tests carried out on optical and infrared stellar spectra to evaluate the accuracy of different types of interpolation. Both model atmospheres and continuum normalized fluxes were interpolated. In the first case we used linear…
Accurately known stellar lithium abundances may be used to shed light on a variety of astrophysical phenomena such as Big Bang nucleosynthesis, radial migration, ages of stars and stellar clusters, and planet engulfment events. We present a…
Context: The full spectrum fitting of stellar spectra against a library of empirical spectra is a well-established approach to measure the atmospheric parameters of FGK stars with a high internal consistency. Extending it towards cooler…
We compare high resolution infrared observations of the CO 3-1 bands in the 2.297-2.310 micron region of M dwarfs and one L dwarf with theoretical expectations. We find a good match between the observational and synthetic spectra throughout…
We investigate statistical equilibrium of Cr in the atmospheres of late-type stars. The main goal is to ascertain the reason for a systematic abundance discrepancy between Cr I and Cr II lines, which is often encountered in spectroscopic…
We present a new method for replacing the outermost layers of stellar models with interpolated atmospheres based on results from 3D simulations, in order to correct for structural inadequacies of these layers. This replacement is known as…
In this work we present first results of our current project aimed at combining the 3D hydrodynamical stellar atmosphere approach with non-LTE (NLTE) spectral line synthesis for a number of key chemical species. We carried out a full…
Aims: Hydrogen and helium line spectra are crucial diagnostic features for the quantitative analysis of OB stars. We compute synthetic spectra based on a hybrid non-LTE approach in order to test the ability of these models to reproduce…