Related papers: Synthetic spectra for O and B type subdwarf stars
We present a new grid of LTE model atmospheres for weakly magnetic (B<=10e10G) neutron stars, using opacity and equation of state data from the OPAL project and employing a fully frequency- and angle-dependent radiation transfer. We discuss…
Present X-ray missions like Chandra and XMM-Newton provide high-resolution and high-S/N observations of extremely hot white dwarfs, e.g. burst spectra of novae. Their analysis requires adequate Non-LTE model atmospheres. The T\"ubingen…
We describe our NLTE codes which allow the computation of synthetic spectra of hot stars and accretion disks. They can be combined to compute ionizing fluxes from the hot component in symbiotic stars.
% context heading (optional) {With the development of new polarimeters for large telescopes, the spectro-polarimetric study of astrophysical bodies is becoming feasible and, indeed, more frequent. In particular, this is permitting the…
We test our knowledge of the atomic opacity in the solar UV spectrum. Using the atomic data compiled in Paper I from modern, publicly available, databases, we perform calculations that are confronted with space-based observations of the…
A new generative technique is presented in this paper that uses Deep Learning to reconstruct stellar spectra based on a set of stellar parameters. Two different Neural Networks were trained allowing the generation of new spectra. First, an…
Modern investigations of magnetic chemically peculiar stars reveal a variety of complex processes in their atmospheres. Realistic spectrum synthesis modelling of these objects has to take into account anomalous chemical composition, strong…
A new extensive grid of synthetic Str{\"o}mgren colors and bolometric corrections is presented for F-M type dwarf and giant stars having 3000K $\leq$ T$_{\rm{eff}}$ $\leq$ 8000K, 0.0 $\leq$ log $g$ $\leq$ 5.0, and -3.0 $\leq$ [Fe/H] $\leq$…
Large spectroscopic surveys of individual massive stars, such as ULLYSES and XSHOOTU, provide observational data for hundreds of massive stars. Their analysis requires large numbers of synthetic spectra so that stellar parameters can be…
The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in chemical composition of their atmospheres. For example, atmospheres of thermally - emitting neutron stars in supernova remnants…
We describe a self-consistent spectrum analysis technique employing non-LTE line formation, which allows precise atmospheric parameters of massive stars to be derived: 1sigma-uncertainties as low as ~1% in effective temperature and…
We construct a comprehensive model atom for TiI-II using more than 3600 measured and predicted energy levels of TiI and 1800 energy levels of TiII, and quantum mechanical photoionisation cross-sections. Non-local thermodynamical equilibrium…
We investigate statistical equilibrium of neutral and singly-ionized strontium in late-type stellar atmospheres. Particular attention is given to the completeness of the model atom, which includes new energy levels, transition…
A new model atom of nitrogen was developed using the energy levels of N I from laboratory measurements and also predicted in atomic structure calculations and the most up-to-date atomic data for computing radiative and collisional rates of…
Methods of calculation of NLTE model atmosphere are discussed. The NLTE trace element procedure is compared with the full NLTE model atmosphere calculation. Differences between LTE and NLTE atmosphere modeling are evaluated. The ways of…
The goals of this work are to develop a new method to separate early and late type stellar components of a dense stellar cluster based on narrow band filters, to apply it to the central parsec of the GC, and to conduct a population analysis…
We have obtained ultra-high quality spectra (R=180,000; S/N>300) with unprecedented wavelength coverage (4400 to 7400 A) for a number of stars covering most of the HR diagram in order to test the predictions of models of stellar surface…
In this paper, I present a new set of synthetic spectral energy distributions (SEDs) for young stellar objects (YSOs) spanning a wide range of evolutionary stages, from the youngest deeply embedded protostars to pre-main-sequence stars with…
We present a semi-empirical spectral classification scheme for normal B-type stars using near-infrared spectra (1.5-1.7 $\mu$m) from the SDSS APOGEE2-N DR14 database. The main motivation for working with B-type stars is their importance in…
Theoretical stellar libraries have been increasingly used to overcome limitations of empirical libraries, e.g. by exploring atmospheric parameter spaces not well represented in the latter. This work presents a new theoretical library which…