Line Profiles of the Calcium I Resonance Line in Cool Metal-polluted White Dwarfs
| Autor: | Simon Blouin, Nicole F. Allard, Florent Xavier Gadea, Thierry Leininger, P. Dufour |
|---|---|
| Přispěvatelé: | Observatoire du Mont Mégantic et Département de Physique, Université de Montréal, Université de Montréal (UdeM), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse) |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Planetesimal
WD 2251-070) -white dwarfs 010504 meteorology & atmospheric sciences Opacity FOS: Physical sciences chemistry.chemical_element Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Spectral line line: profiles -opacity -stars: individual (SDSS J08044063+2239486 Atmosphere 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Helium Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences Line (formation) Earth and Planetary Astrophysics (astro-ph.EP) Physics [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] White dwarf Astronomy and Astrophysics WD J2356-209 Stars chemistry Astrophysics - Solar and Stellar Astrophysics 13. Climate action Space and Planetary Science Astrophysics::Earth and Planetary Astrophysics Astrophysics - Earth and Planetary Astrophysics |
| Zdroj: | The Astrophysical Journal The Astrophysical Journal, American Astronomical Society, 2019, 875 (2), pp.137. ⟨10.3847/1538-4357/ab1266⟩ |
| ISSN: | 0004-637X 1538-4357 |
| DOI: | 10.3847/1538-4357/ab1266⟩ |
| Popis: | Metal-polluted white dwarfs (DZ stars) are characterized by a helium-rich atmosphere contaminated by heavy elements traces originating from accreted rocky planetesimals. As a detailed spectroscopic analysis of those objects can reveal the composition of the accreted debris, there is a great interest in developing accurate DZ atmosphere models. However, the coolest DZ white dwarfs are challenging to model due to the fluidlike density of their atmospheres. Under such extreme conditions, spectral absorption lines are heavily broadened by interactions with neutral helium and it is no longer justified to use the conventional Lorentzian profiles. In this work, we determine the theoretical profiles of the Ca I resonance line (the most prominent spectral line for the coolest DZ white dwarfs) in the dense atmospheres of cool DZ white dwarfs. To do so, we use a unified theory of collisional line profiles and accurate ab initio potential energies and transition dipole moments for the CaHe molecule. We present the resulting profiles for the full range of temperatures and helium densities relevant for the modeling of cool, metal-polluted white dwarfs (from 3000 to 6000 K and from $10^{21}$ to $10^{23}\,{\rm cm}^{-3}$). We also implement these new profiles in our atmosphere models and show that they lead to improved fits to the Ca I resonance line of the coolest DZ white dwarfs. 6 pages, 9 figures, 1 table. Accepted for publication in The Astrophysical Journal |
| Databáze: | OpenAIRE |
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