Related papers: Uncertainties in stellar abundance analyses
Ever since the discovery of neutron stars it has been realized that they serve as probes of a physical regime that cannot be accessed in laboratories: strongly degenerate matter at several times nuclear saturation density. Existing nuclear…
Orbital solutions for binary or multiple stellar systems that combine astrometry (e.g., position angles and angular separations) with spectroscopy (radial velocities) have important advantages over astrometric-only or spectroscopic-only…
We summarize some of the compelling new scientific opportunities for understanding stars and stellar systems that can be enabled by sub-milliarcsec (sub-mas) angular resolution, UV-Optical spectral imaging observations, which can reveal the…
The past decade has led to significant improvements in our understanding of the physical structure of the molecular cores of cold dark clouds. Observational efforts, in combination with improved knowledge of cloud structure, now provide…
High-fidelity spectroscopy presents challenges for both observations and in designing instruments. High-resolution and high-accuracy spectra are required for verifying hydrodynamic stellar atmospheres and for resolving intergalactic…
Beginning with a historical account of the spectral classification, its refinement through additional criteria is presented. The line strengths and ratios used in two dimensional classifications of each spectral class are described. A…
To analyse stellar populations in galaxies a widely used method is to apply theoretically derived responses of stellar spectra and line indices to element abundance variations, hereafter referred to as response functions. These are applied…
Black holes and neutron stars present extreme forms of matter that cannot be created as such in a laboratory on Earth. Instead, we have to observe and analyze the experiments that are ongoing in the Universe. The most telling observations…
An overview of selected topical problems on modelling oscillation properties in solar-like stars is presented. High-quality oscillation data from both space-borne intensity observations and ground-based spectroscopic measurements provide…
Spectroscopic analyses with the intention of the interpretation of the UV-spectra of the brightest stars as individuals - supernovae - or as components of star-forming regions - massive O stars - provide a powerful tool with great…
Elemental abundance ratios as tracers of stellar populations are discussed with emphasis on F, G, and K stars providing a `fossil' record of the chemical evolution of the Galaxy. Most abundance studies have been based on homogeneous 1D…
The current state-of-the-art of population synthesis is reviewed. The field is currently undergoing major revisions with the recognition of several key processes as new critical ingredients. Stochastic effects can artificially enhance or…
I provide an overview of the empirical mass-loss rates of hot and cool luminous stars. Stellar species included in this talk are luminous OB stars, Wolf-Rayet stars, asymptotic giant branch stars, and red supergiants. I discuss the scaling…
Molecular clouds are the principle stellar nurseries of our universe, keeping them in the focus of both observational and theoretical studies. From observations, some of the key properties of molecular clouds are well known but many…
The abundance patterns of metal-poor stars provide us a wealth of chemical information about various stages of cosmic chemical evolution. In particular, these stars allow us to study the formation and evolution of the elements, and the…
While there has been significant progress in our understanding of the origin and evolu-tion of planetary nebulae in the last 50 years, there remain several unsolved problems. These include the true 3D morphological structure of the nebulae,…
There has been remarkable progress recently in both observational and theoretical studies of galaxy formation and evolution. Largely due to a combination of deep Hubble Space Telescope imaging, Keck spectroscopy, and COBE far-IR background…
Statistical inference in observational science typically relies on a fundamental assumption: as sample size increases and uncertainties decrease, the inferred results should converge to the true physical quantities. This assumption…
Binary star systems are assumed to be co-natal and coeval, thus to have identical chemical composition. In this work we aim to test the hypothesis that there is a connection between observed element abundance patterns and the formation of…
Emission and absorption line observations of molecules in late-type stars are a vital component in our understanding of stellar evolution, dust formation and mass loss in these objects. The molecular composition of the gas in the…