Related papers: MARCS model atmospheres
We present a grid of spherically symmetric model atmospheres for young pre-MS stars. This grid spans the parameter range $2000\K \leq \Teff \leq 6800\K$ and $2.0 \leq \logg \leq 3.5$ for $M=0.1\Msun$, appropriate for low mass stars and…
We have calculated a grid of more than 700 model atmospheres valid for a wide range of parameters encompassing the coolest known M~dwarfs, M~subdwarfs and brown dwarf candidates: $1500\le \teff \le 4000\,$K, $3.5\le \log(g)\le 5.5$, and…
The first in-situ measurements of the altitude profile of Martian upper atmospheric density and composition were carried out by the Viking lander missions in 1976. The MAVEN and MOM spacecraft launched in September 2014 with mass…
Grids of stellar models are useful tools to derive the properties of stellar clusters, in particular young clusters hosting massive stars, and to provide information on the star formation process in various mass ranges. Because of their…
Spherical hydrodynamic models with a polytropic equation of state (EoS) for forming protostars are revisited in order to investigate the so-called luminosity conundrum highlighted by observations. For a molecular cloud (MC) core with such…
presented. The 2.38 -- 4.08 micron wavelength-range of band 1 of ISO-SWS (Short-Wavelength Spectrometers on board of the Infrared Space Observatory) in which many different molecules -- with their own dependence on each of the stellar…
Since the end of 2018, the Transiting Exoplanet Survey Satellite (TESS) has provided stellar photometry to the astronomical community. We have used TESS data to study rotational modulation in the light curves of a sample of chemically…
We present a compilation of multiwavelength data on different star formation indicators for a sample of nearby star forming galaxies. Here we discuss the observations, reductions and measurements of ultraviolet images obtained with STIS, on…
Mass-to-light versus colour relations (MLCRs), derived from stellar population synthesis models, are widely used to estimate galaxy stellar masses (M$_*$) yet a detailed investigation of their inherent biases and limitations is still…
We study the spectroscopic and photometric properties of carbon stars. In the first paper of this series we focus on objects that can be described by hydrostatic models neglecting dynamical phenomena like pulsation and mass loss. As a…
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…
Context: Among late-type red giants, an interesting change occurs in the structure of the outer atmospheric layers as one moves to later spectral types in the Hertzsprung-Russell diagram: a chromosphere is always present, but the coronal…
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,…
We have a developed a new method for fitting spectral energy distributions (SEDs) to identify and constrain the physical properties of high-redshift (4 < z < 8) galaxies. Our approach uses an implementation of Bayesian based Markov Chain…
CO spectral line formation in the Sun has long been a source of consternation for solar physicists, as have the elemental abundances it seems to imply. We modelled solar CO line formation using a realistic, ab initio, time-dependent 3D…
Mesospheric CO2 clouds are one of two types of carbon dioxide clouds known on Mars. We present observations of mesospheric CO2 clouds made by Atmospheric Chemistry Suit (ACS) onboard the ESA-Roscosmos ExoMars Trace Gas Orbiter (TGO). We…
Context: Data from ground-based, high-resolution solar telescopes can only be used for science with calibrations and processing, which requires detailed knowledge about the instrumentation. [...] Aims: We aim to provide observers with a…
Interpreting the Stokes profiles observed in quiet regions of the solar chromosphere is a challenging task. The Stokes Q and U profiles are dominated by the scattering polarisation and the Hanle effect, and these processes can only be…
Red supergiants (RSGs) are evolved massive stars in a stage preceding core-collapse supernova. The physical processes that trigger mass loss in their atmospheres are still not fully understood. Based on observations of $\alpha$ Ori, a new…
Simulated exoplanet transmission spectra are critical for planning and interpretation of observations and to explore the sensitivity of spectral features to atmospheric thermochemical processes. We present a publicly available generic model…