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We present an outline of basic assumptions and governing structural equations describing atmospheres of substellar mass objects, in particular the extrasolar giant planets and brown dwarfs. Although most of the presentation of the physical…
The use of machine learning is becoming ubiquitous in astronomy, but remains rare in the study of the atmospheres of exoplanets. Given the spectrum of an exoplanetary atmosphere, a multi-parameter space is swept through in real time to find…
The growth of sky surveys and the large amount of stellar spectra in the current databases, has generated the necessity of developing new methods to estimate atmospheric parameters, a fundamental task on stellar research. In this work we…
Modeling the atmospheres of exoplanets is fundamental to understanding their atmospheric physics and chemical processes. While one-dimensional (1D) atmospheric models with 1D radiative transfer (RT) have been widely used, advances in…
Multi-channel satellite imagery, from stacked spectral bands or spatiotemporal data, have meaningful representations for various atmospheric properties. Combining these features in an effective manner to create a performant and trustworthy…
We calculate a grid of spherically symmetric OB stellar atmospheres at low metallicities, including both non-local thermodynamic equilibrium (NLTE) and metal line blanketing effects. This is done to assess the uncertainties in helium…
The chemical compositions of stars encode the history of the universe and are thus fundamental for advancing our knowledge of astrophysics and cosmology. However, measurements of elemental abundances ratios, and our interpretations of them,…
The construction and implementation of atmospheric model grids is a popular tool in exoplanet characterisation. These typically vary a number of parameters linearly, containing one model for every combination of parameter values. Here we…
In the era of the James Webb Space Telescope (JWST), the dramatic improvement in the spectra of exoplanetary atmospheres demands a corresponding leap forward in our ability to analyze them: atmospheric retrievals need to be performed on…
Clustering is an effective tool for astronomical spectral analysis, to mine clustering patterns among data. With the implementation of large sky surveys, many clustering methods have been applied to tackle spectroscopic and photometric data…
Theoretical spectral energy distributions (SEDs) of white dwarfs provide a powerful tool for cross-calibration and sensitivity control of instruments from the far infrared to the X-ray energy range. Such SEDs can be calculated from fully…
Earth's atmosphere imprints a large number of telluric absorption and emission lines on astronomical spectra, especially in the near infrared, that need to be removed before analysing the affected wavelength regions. These lines are…
We present a new spectroscopic pipeline designed to analyse large numbers of hot massive stars homogeneously. The pipeline has been developed to utilise large grids of FASTWIND non-LTE, line blanketed models in which spherical geometry is…
We present a theoretical study of the effects and signatures of realistic velocity field and atmospheric inhomogeneities associated with convective motions at the surface of cool late-type stars on the emergent profiles of iron spectral…
The search for Earth-like exoplanets requires high-contrast and high-angular resolution instruments, which designs can be very complex: they need an adaptive optics system to compensate for the effect of the atmospheric turbulence on image…
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…
Context. Obtaining precise stellar and wind properties and abundance patterns of massive stars is crucial to understanding their nature and interactions with their environments, as well as to constrain their evolutionary paths and…
Spectral diagnostic features formed in the solar chromosphere are few and difficult to interpret -- they are neither formed in the optically thin regime nor in local thermodynamic equilibrium (LTE). To probe the state of the chromosphere,…
Observational studies of exoplanets are suggestive of a ubiquitous presence of clouds. The current modelling techniques used in emission to account for the clouds tend to require prior knowledge of the cloud condensing species and often do…
In the framework of the Virtual Observatory, the newly developed service TheoSSA provides access to theoretical stellar spectral-energy distributions. In a pilot phase, this service is based on the well established Tuebingen NLTE…