Related papers: The electron temperature in ionized nebulae
We have conducted a large-scale survey of 120 planetary nebulae (PNe) to search for the near-infrared emission lines [Kr III] 2.199 and [Se IV] 2.287 microns. The neutron(n)-capture elements Se and Kr may be enriched in a PN if its…
We suggest a new way to establish the relation between the electron temperature t3 within the [OIII] zone and the electron temperature t2 within the [OII] zone in high-metallicity (12+log(O/H) > 8.25) HII regions. The t2 - t3 diagram is…
We analyse a sample of 225 star-forming regions from the DESIRED-E project, each with simultaneous determinations of the electron temperature from ionized nitrogen and oxygen, $T_{\rm e}$([NII]) and $T_{\rm e}$([OIII]), respectively. We…
We present new computations of the equilibrium and non-equilibrium cooling efficiencies and ionization states for low-density radiatively cooling gas containing cosmic abundances of the elements H, He, C, N, O, Ne, Mg, Si, S, and Fe. We…
Thermal instability in an electron-ion magnetized plasma, which is relevant in the intragalactic medium (IGM) of galaxy clusters, solar corona, and other two-component plasma objects is investigated. We apply the multicomponent plasma…
In this summary I review some results relative to: planetary nebulae, H II regions, chemical evolution of galaxies, and the determination of the primordial helium abundance. These results were presented during the symposium "Ionized Gaseous…
Of the light element abundances capable of testing standard big bang nucleosynthesis, only He4 is measured with an accuracy of a few percent. Thus, it is imperative to establish a comprehensive technique for determining He4 abundances and…
Deriving oxygen abundances from the electron temperature (hereafter the $T_e$-method) is the gold-standard for extragalactic metallicity studies. However, unresolved temperature fluctuations within individual HII regions and across…
The metallicities implied by collisionally excited lines (CELs) of heavy elements in H II regions are systematically lower than those implied by recombination lines (RLs) by factors ~2, introducing uncertainties of the same order in the…
We present long-slit spectrophotometric observations in the red and near infrared of 12 HII galaxies. The spectral range includes the sulphur lines [SII] at wavelengths 6716, 6731 angstroms and [SIII] at 6312 angstroms and 9069, 9532…
Methods to determine abundances of the elements in the atmospheres of F, G, and K stars with precisions of 0.01-0.03 dex are reviewed. Such high-precision stellar abundances have led to the discovery of unexpected phenomena and relations…
The discrepancy between the oxygen abundances in high-metallicity HII regions determined through the Te-method (and/or through the corresponding "strong lines - oxygen abundance" calibration) and that determined through the model fitting…
The aim of the paper is to determine abundances in a group of PNe with uniform morphology. The PNe discussed are circular excited by rather low-temperature central stars. The relation between abundance and evolution is discussed. The…
We report the abundances of 30 elements in 23 metal-poor ([Fe/H] <-1.7) giants. These are based on 7774 equivalent widths and spectral synthesis of 229 additional lines. Hyperfine splitting is taken into account when appropriate. Our choice…
We report on our studies of the physical structure of the planetary nebula (PN) NGC7662. Using (3D) Integral Field Spectroscopy we have been able to measure the electron temperature more accurately and at a larger number of radial locations…
Traditionally, it is understood that fluctuations in the equilibrium distribution are not evident in thermodynamic systems of large $N$ (the number of particles in the system) \cite{Huang1}. In this paper we examine the validity of this…
The analysis of X-ray and Sunyaev-Zel\'dovich measurements of the intracluster medium (ICM) assumes that electrons are in thermal equilibrium with ions in the plasma. However, electron-ion equilibration timescales can be comparable to the…
Non-local thermodynamic equilibrium (NLTE) line formation for neutral and singly-ionized iron is considered through a range of stellar parameters characteristic of cool stars. A comprehensive model atom for Fe I and Fe II is presented. Our…
A mayor problem that arises in the computation of stellar atmosphere models is the self consistent determination of the temperature distribution via the constraint of energy conservation. The energy balance includes the gains due to the…
The electronic distribution in devices with sufficiently small diemnsions may not be in thermal equilibrium with their surroundings. Systems where the occupancies of electronic states are solely determined by tunneling processes are…