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We discuss the determination of elemental abundances from high resolution X-ray data. We emphasize the need for an accurate determination of the underlying temperature structure and advocate the use of a line ratio method which allows us to…

Astrophysics · Physics 2009-11-10 J. H. M. M. Schmitt , J. -U. Ness

We present a set of gas-phase Planck mean and Rosseland mean opacity tables applicable for simulations of star and planet formation, stellar evolution, disk modelling at various metallicities in hydrogen-rich environments. The tables are…

Solar and Stellar Astrophysics · Physics 2015-05-13 Ch. Helling , W. Lucas

We discuss the role of the electron temperature in abundance determinations in ionized nebulae (planetary nebulae and giant HII regions). We show that, even when observations provide a direct estimate of Te, abundance determinations may…

Astrophysics · Physics 2007-05-23 Grazyna Stasinska

Transmission spectroscopy of exoplanets has the potential to provide precise measurements of atmospheric chemical abundances, in particular of hot Jupiters whose large sizes and high temperatures make them conducive to such observations. To…

Earth and Planetary Astrophysics · Physics 2018-11-07 Arazi Pinhas , Nikku Madhusudhan , Siddharth Gandhi , Ryan J. MacDonald

Hydrogen is a promising energy carrier, yet its practical deployment is limited by the lack of storage materials that simultaneously achieve high storage capacity ($w$) and practical equilibrium pressure at room temperature ($P_{\rm…

We determine the elemental abundances for the ejecta of the slow nova PW Vul 1984. Our technique uses a minimization of the emission line fits of a photoionization model to available ultraviolet, optical and infrared spectra. We find the…

Astrophysics · Physics 2015-06-24 Greg J. Schwarz , S. Starrfield , Steven N. Shore , Peter H. Hauschildt

Abridged: We detail and benchmark two sophisticated chemical models developed by the Heidelberg and Bordeaux astrochemistry groups. The main goal of this study is to elaborate on a few well-described tests for state-of-the-art astrochemical…

Astrophysics of Galaxies · Physics 2015-05-19 D. Semenov , F. Hersant , V. Wakelam , A. Dutrey , E. Chapillon , St. Guilloteau , Th. Henning , R. Launhardt , V. Pietu , K. Schreyer

We propose a methodology to perform a self-consistent analysis of the physical properties of the emitting gas of HII galaxies adequate to the data that can be obtained with the XXI century technology. This methodology requires the…

Astrophysics of Galaxies · Physics 2009-01-21 G. F. Hagele , A. I. Diaz , E. Terlevich , E. Perez-Montero , R. Terlevich , M. V. Cardaci

Designing alloys for additive manufacturing (AM) presents significant opportunities. Still, the chemical composition and processing conditions required for printability (ie., their suitability for fabrication via AM) are challenging to…

Ionized nebulae are key to understanding the chemical composition and evolution of the Universe. Among these nebulae, H~{\sc ii} regions and planetary nebulae are particularly important as they provide insights into the present and past…

Astrophysics of Galaxies · Physics 2023-11-20 José Eduardo Méndez-Delgado , Jorge García-Rojas

In this work, we mainly present the optimal convergence rates of the temporally second-order finite element scheme for solving the electrohydrodynamic equation. Suffering from the highly coupled nonlinearity, the convergence analysis of the…

Numerical Analysis · Mathematics 2025-05-06 Shengfeng Wang , Zeyu Xia , Maojun Li

Aims: ARCiS, a novel code for the analysis of exoplanet transmission and emission spectra is presented. The aim of the modelling framework is to provide a tool able to link observations to physical models of exoplanet atmospheres. Methods:…

Earth and Planetary Astrophysics · Physics 2020-10-07 Michiel Min , Chris W. Ormel , Katy Chubb , Christiane Helling , Yui Kawashima

The theoretical description of non-equilibrium Bose--Einstein condensate (BEC) is one of the main challenges in modern statistical physics and kinetics. The non-equilibrium nature of BEC makes it impossible to employ the well-established…

Quantum Gases · Physics 2022-06-01 V. Yu. Shishkov , E. S. Andrianov , Yu. E. Lozovik

We address disequilibrum abundances of some simple molecules in the atmospheres of solar composition brown dwarfs and self-luminous extrasolar giant planets using a kinetics-based 1D atmospheric chemistry model. Our approach is to use the…

Earth and Planetary Astrophysics · Physics 2015-06-22 Kevin J. Zahnle , Mark S. Marley

Constraining the chemical structure of exoplanetary atmospheres is pivotal for interpreting spectroscopic data and understanding planetary evolution. Traditional retrieval methods often assume thermochemical equilibrium or free profiles,…

Earth and Planetary Astrophysics · Physics 2025-06-17 Deborah Bardet , Quentin Changeat , Olivia Venot , Emilie Panek

Much of our understanding of the internal structure of the Sun derives from so-called standard theoretical solar models. Unfortunately, none of those models agrees completely with observation. The discrepancy is commonly associated with…

Solar and Stellar Astrophysics · Physics 2019-04-10 Douglas Gough

[ABRIDGED]We study the carbon abundances with a twofold objective. On the one hand, we want to evaluate the behaviour of carbon in the context of Galactic chemical evolution. On the other hand, we focus on the possible dependence of carbon…

Solar and Stellar Astrophysics · Physics 2021-12-01 E. Delgado Mena , V. Adibekyan , N. C. Santos , M. Tsantaki , J. I. González Hernández , S. G. Sousa , S. Bertrán de Lis

We have performed a differential, line-by-line, chemical abundance analysis, ultimately relative to the Sun, of nine very metal-poor main sequence halo stars, near [Fe/H]=$-$2 dex. Our abundances range from…

Solar and Stellar Astrophysics · Physics 2017-04-05 Erin O'Malley , Andrew McWilliam , Brian Chaboyer , Ian Thompson

The detections of atomic hydrogen, heavy atoms and ions surrounding the extrasolar giant planet (EGP) HD209458b constrain the composition, temperature and density profiles in its upper atmosphere. Thus the observations provide guidance for…

Earth and Planetary Astrophysics · Physics 2015-06-11 T. T. Koskinen , M. J. Harris , R. V. Yelle , P. Lavvas

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…

Astrophysics · Physics 2009-11-11 Orly Gnat , Amiel Sternberg