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Related papers: Improved Stark Broadened Profiles for Neutral Heli…

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We present new calculations of Stark broadened profiles for neutral helium lines using computer simulations that include some important aspects aimed at better representing the dynamical environment of the helium atom. These include the…

Solar and Stellar Astrophysics · Physics 2020-10-07 Patrick Tremblay , Alain Beauchamp , Pierre Bergeron

We present improved calculations for the Stark broadening of hydrogen lines in dense plasmas typical of white dwarf atmospheres. Our new model is based on the unified theory of Stark broadening from Vidal, Cooper, & Smith. For the first…

Solar and Stellar Astrophysics · Physics 2011-02-11 P. -E. Tremblay , P. Bergeron

Ultracool stellar atmospheres show absorption by alkali resonance lines severely broadened by collisions with neutral perturbers. In the coolest and densest atmospheres, such as those of T dwarfs, Na I and K I broadened by molecular…

Solar and Stellar Astrophysics · Physics 2023-06-21 N. F. Allard , K. Myneni , J. N. Blakely , G. Guillon

We present new calculations for the Stark broadening of the hydrogen line profiles in the dense atmospheres of white dwarf stars. Our improved model is based on the unified theory of Stark broadening from Vidal, Cooper & Smith, but it also…

Solar and Stellar Astrophysics · Physics 2009-07-22 P. -E. Tremblay , P. Bergeron , J. Dupuis

Aims: Hydrogen and helium line spectra are crucial diagnostic features for the quantitative analysis of OB stars. We compute synthetic spectra based on a hybrid non-LTE approach in order to test the ability of these models to reproduce…

Astrophysics · Physics 2009-11-11 M. F. Nieva , N. Przybilla

A new grid of detailed atmosphere model spectra for hot and moderately cool subdwarf stars is presented. High-resolution spectra and synthetic photometry are calculated in the range from 1000{\AA} to 10,000{\AA} using Non-LTE fully…

Solar and Stellar Astrophysics · Physics 2021-10-07 Thayse A. Pacheco , Marcos P. Diaz , Ronaldo S. Levenhagen , Paula R. T. Coelho

White dwarf stars are traditionally found to have surface compositions made primarily of hydrogen or helium. However, a new family has recently been uncovered, the so-called Hot DQ white dwarfs, which have surface compositions dominated by…

Solar and Stellar Astrophysics · Physics 2018-03-14 P. Dufour , N. Ben Nessib , S. Sahal-Bréchot , M. S. Dimitrijević

We present a comprehensive investigation of He I line profile calculations used in the spectroscopic analyses of DB white dwarfs. Our study includes an in-depth photometric and spectroscopic analysis of all DB white dwarfs in the Data…

Solar and Stellar Astrophysics · Physics 2026-04-14 Patrick Tremblay , Pierre Bergeron , Alain Beauchamp

Stark broadening theory is currently operated for calculating widths and shifts of spectral lines that are needed for spectroscopic diagnostics and modelling in astrophysics, laboratory and technological plasmas. We have calculated a great…

Solar and Stellar Astrophysics · Physics 2018-03-14 Sylvie Sahal-Brechot , Milan S. Dimitrijevic , Nebil Ben Nessib

We examine the emergent fluxes from helium-core white dwarfs following their evolution from the end of pre-white dwarf stages down to advanced cooling stages. For this purpose, we include a detailed treatment of the physics of the…

Astrophysics · Physics 2009-11-07 R. D. Rohrmann , A. M. Serenelli , L. G. Althaus , O. G. Benvenuto

Using the semiclassical perturbation method, electron-, proton-, and ionized helium-impact line widths and shifts for the nine Cr I spectral lines from the $4p^7P^0-4d^7D$ multiplet, have been calculated for a perturbers density of…

Astrophysics · Physics 2009-11-10 M. S. Dimitrijevic , T. Ryabchikova , L. C. Popovic , D. Shulyak , S. Khan

Stark broadening parameters for 157 multiplets of helium like boron (B IV) have been calculated using the impact semiclassical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series.…

Solar and Stellar Astrophysics · Physics 2016-05-25 Milan S. Dimitrijevic , Magdalena Christova , Zoran Simic , Andjelka Kovacevic , Sylvie Sahal-Brechot

In order to complete Stark broadening data for Ne II, and O III lines, needed for analysis of stellar atmospheres, we determined, within the semiclassical perturbation method, the missing Stark broadening parameters for the broadening by…

Solar and Stellar Astrophysics · Physics 2018-03-14 Milan S. Dimitrijevic , Andjelka Kovacevic , Zoran Simic , Sylvie Sahal-Brechot

Besides the need of Stark broadening parameters for a number of problems in physics, and plasma technology, in hot star atmospheres the conditions exist where Stark widths are comparable and even larger than the thermal Doppler widths.…

Solar and Stellar Astrophysics · Physics 2018-03-14 Z. Simic , M. S. Dimitrijevic , A. B. Kovacevic , S. Sahal-Brechot

We present the first grid of 3D simulations for the pure-helium atmospheres of DB white dwarfs. The simulations were computed with the CO5BOLD radiation-hydrodynamics code and cover effective temperatures and surface gravities between 12000…

Solar and Stellar Astrophysics · Physics 2018-09-05 E. Cukanovaite , P. -E. Tremblay , B. Freytag , H. -G. Ludwig , P. Bergeron

We present a comprehensive grid of synthetic stellar-atmosphere spectra, suitable for the analysis of high resolution spectra of hydrogen-deficient post-Asymptotic Giant Branch (post-AGB) objects hotter than 50000 K, migrating along the…

Solar and Stellar Astrophysics · Physics 2012-11-02 Graziela R. Keller , James E. Herald , Luciana Bianchi , Walter J. Maciel , Ralph C. Bohlin

As part of our laboratory investigation of the theoretical line profiles used in white dwarf atmosphere models, we extend the electron-density ($n_{\rm e}$) range measured by our experiments to higher densities (up to…

Solar and Stellar Astrophysics · Physics 2016-09-30 Ross E. Falcon , J. E. Bailey , T. A. Gomez , M. Schaeuble , T. Nagayama , M. H. Montgomery , D. E. Winget , G. A. Rochau

There is an ongoing interest in using spectroscopy in inertial confinement fusion (ICF) experiments, where dopants such as krypton can provide vital information about the temperature and density of the imploding plasma. While the most…

Plasma Physics · Physics 2025-12-08 G. Pérez-Callejo , E. Stambulchik , R. Florido , M. A. Gigosos

We have conducted a spectroscopic survey of over 1300 bright (V < 17.5), hydrogen-rich white dwarfs based largely on the last published version of the McCook & Sion catalog. The complete results from our survey, including the spectroscopic…

Solar and Stellar Astrophysics · Physics 2015-05-30 Alexandros Gianninas , Pierre Bergeron , Maria Teresa Ruiz

We have combined the detailed He I recombination model of Smits with the collisional transitions of Sawey & Berrington in order to produce new accurate helium emissivities that include the effects of collisional excitation from both the 2…

Astrophysics · Physics 2009-10-31 Robert A. Benjamin , Evan D. Skillman , Derck P. Smits
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