Non-LTE line-formation for hydrogen revisited

Abstract

We discuss aspects of non-LTE line formation for hydrogen in early-type stars. We evaluate the effect of variations in the electron-impact excitation cross sections in model atoms of differing complexity by comparison with observation. While the Balmer lines are basically unaffected by the choice of atomic data, the Paschen, Brackett and Pfund series members allow us to discriminate between the different models. Non-LTE calculations based on the widely-used approximation formulae of Mihalas, Heasley & Auer and of Johnson fail to simultaneously reproduce the optical and IR spectra over the entire parameter range. The use of data from ab-initio calculations up to principal quantum number n<=7 largely solves the problem. We recommend a reference model using the available data. This model is of general interest because of the ubiquity of the hydrogen spectrum.

34 pages, 14 figures, 4 tables

References in corpus (4)

• Revised Stellar Temperatures for Magellanic Cloud O Supergiants from FUSE and VLT-UVES Spectroscopy
• Constraints on the Ionization Balance of Hot-Star Winds from FUSE Observations of O Stars in the Large Magellanic Cloud
• Near-Infrared Classification Spectroscopy: J-Band Spectra of Fundamental MK Standards
• Stagnation and Infall of Dense Clumps in the Stellar Wind of tau Scorpii

Cited by in corpus (76)

• Present-day cosmic abundances. A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models
• Atmospheric NLTE-Models for the Spectroscopic Analysis of Blue Stars with Winds. II. Line-Blanketed Models
• A cosmic abundance standard: chemical homogeneity of the solar neighbourhood and the ISM dust-phase composition
• L-band spectroscopy of Galactic OB-stars
• Quantitative Spectroscopy of BA-type Supergiants
• The hot subdwarf B + white dwarf binary KPD 1930+2752 - a Supernova Type Ia progenitor candidate
• Non-LTE line formation for heavy elements in four very metal-poor stars
• Hydrogen and helium line formation in OB dwarfs and giants. A hybrid non-LTE approach
• The chemical composition of the Orion star-forming region. III. C, N, Ne, Mg and Fe abundances in B-type stars revisited
• Testing common classical LTE and NLTE model atmosphere and line-formation codes for quantitative spectroscopy of early-type stars
• Effective temperature determinations of late-type stars based on 3D non-LTE Balmer line formation
• NGC 1866: First Spectroscopic Detection of Fast Rotating Stars in a Young LMC Cluster
• Discovery of extended main sequence turn offs in Galactic open clusters
• Different stellar rotation in the two main sequences of the young globular cluster NGC1818: first direct spectroscopic evidence
• Carbon abundances of early B-type stars in the solar vicinity. Non-LTE line-formation for C II/III/IV and self-consistent atmospheric parameters
• C II abundances in early-type stars: solution to a notorious non-LTE problem
• Non-LTE modelling of the HeI 10830A line in early-type main sequence stars
• Quantitative H and K band spectroscopy of Galactic OB-stars at medium resolution
• Oxygen abundances in metal-poor subgiants as determined from [O I], O I and OH lines
• A Bake-Off Between CMFGEN and FASTWIND: Modeling the Physical Properties of SMC and LMC O-type Stars
• Rapid escape of ultra-hot exoplanet atmospheres driven by Hydrogen Balmer absorption
• LMC origin of the hyper-velocity star HE 0437-5439. Beyond the supermassive black hole paradigm
• HD 271791: An Extreme Supernova Runaway B Star Escaping from the Galaxy
• The Hanle Effect of the Hydrogen Ly-alpha Line for Probing the Magnetism of the Solar Transition Region
• Spectral modeling of type II supernovae. I. Dilution factors
• Non-LTE Balmer line formation in late-type spectra: Effects of atomic processes involving hydrogen atoms
• Photochemistry and Heating/Cooling of the Multiphase Interstellar Medium with UV Radiative Transfer for Magnetohydrodynamic Simulations
• A new method for an objective, ${\chi }^2$-based spectroscopic analysis of early-type stars
• Quantitative spectroscopy of Deneb
• Quantitative spectroscopy of Galactic BA-type supergiants. I. Atmospheric parameters
• The solar hydrogen spectrum in non-LTE
• HVS7: a chemically peculiar hyper-velocity star
• The scattering polarization of the Ly-alpha lines of H I and He II taking into account PRD and J-state interference effects
• A quantitative in-depth analysis of the prototype sdB+BD system SDSS J08205+0008 revisited in the Gaia era
• A new method for the inversion of atmospheric parameters of A/Am stars
• B fields in OB stars (BOB): Detection of a magnetic field in the He-strong star CPD-57° 3509
• CRIRES-POP: A library of high resolution spectra in the near-infrared
• Extreme helium stars: non-LTE matters Helium and hydrogen spectra of the unique objects V652 Her and HD144941
• Solar and Stellar Photospheric Abundances
• Discovery of magnetic A supergiants: the descendants of magnetic main sequence B stars
• Angular momentum changing transitions in proton-Rydberg atom collisions
• Quantitative spectroscopy of B-type supergiants
• The effects of surface fossil magnetic fields on massive star evolution: III. The case of $\tau$ Sco
• CRIRES high-resolution near-infrared spectroscopy of diffuse interstellar band profiles. Detection of 12 new DIBs in the YJ band and the introduction of a combined ISM sight line and stellar analysis approach
• High-mass eclipsing binaries: a testbed for models of interior structure and evolution -- Accurate fundamental properties and surface chemical composition for V1034 Sco, GL Car, V573 Car and V346 Cen
• Quantitative spectroscopy of late O-type main-sequence stars with a hybrid non-LTE method
• Weighing the Galactic dark matter halo: a lower mass limit from the fastest halo star known
• Physical Properties of the B and Be Star Populations of h and chi Persei
• Scattering Polarization of Hydrogen Lines in Weakly Magnetized Stellar Atmospheres I. Formulation and Application to Isothermal Models
• On the Probable Existence of an Abrupt Magnetization in the Upper Chromosphere of the Quiet Sun
• Magnetic sensitivity in the wing scattering polarization signals of the hydrogen Lyman-alpha line of the solar disk radiation
• The transfer of polarized radiation in resonance lines with partial frequency redistribution, J-state interference, and arbitrary magnetic fields. A radiative transfer code and useful approximations
• Quantitative spectroscopy of extreme helium stars - Model atmospheres and a non-LTE abundance analysis of BD+10${}^{\circ }$2179?
• SHOTGLAS II. MUSE spectroscopy of blue horizontal branch stars in the core of $\omega$ Centauri and NGC 6752
• The Atomic Physics Underlying the Spectroscopic Analysis of Massive Stars and Supernovae
• A halo blue straggler on a highly eccentric retrograde orbit
• Comprehensive rate coefficients for electron collision induced transitions in hydrogen
• NLTE spectroscopic analysis of the ${}^3$He anomaly in subluminous B-type stars
• B fields in OB stars (BOB): The magnetic triple stellar system HD 164492C in the Trifid nebula
• HD144941: The most extreme helium-strong star
• The blue supergiant Sher 25 revisited in the Gaia era
• Observations of the Ultraviolet-Bright Star Barnard 29 in the Globular Cluster M13 (NGC 6205)
• Non-LTE Model Atom Construction
• To clump or not to clump The impact of wind inhomogeneities on the optical and NIR spectroscopic analysis of massive OB stars
• A non-LTE spectral analysis of the 3He and 4He isotopes in the HgMn star kappa Cancri
• Non-LTE Modelling of the Structure and Spectra of the Hot Accretion Spots on the Surface of Young Stars
• Helium stratification in HD 145792: a new Helium strong star
• Soft X-ray heating as a mechanism of optical continuum generation in solar-type star superflares
• A numerical approach for modelling the polarisation signals of strong resonance lines with partial frequency redistribution. Numerical applications to two-term atoms and plane-parallel atmospheres
• The Puzzling Spectrum of HD 94509
• Quantitative spectroscopy of multiple OB stars: I. The quadruple system HD 37061 at the centre of Messier 43
• Non-Maxwellian rate coefficients for electron and ion collisions in Rydberg plasmas: implications for excitation and ionization
• Non-LTE Line Formation in the Near-IR: Hot Stars
• MUSE crowded field 3D spectroscopy in NGC 300 II. Quantitative spectroscopy of BA-type supergiants
• First JWST/NIRSpec Spectroscopy of O Stars in the Small Magellanic Cloud
• Scattering polarization and the Hanle effect in H-alpha as a probe of chromospheric magnetism: Modeling vs. Observations