Theoretical and laboratory spectra of sodium perturbed by molecular hydrogen

Allard, N. F.; Kielkopf, John F.; Spiegelman, Fernand; Tinetti, Giovanna; Beaulieu, J. P.

doi:10.1051/0004-6361/201219037

Cited by 28 publications

(35 citation statements)

References 42 publications

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“…Recent work by Allard et al (2012) on these line shapes should improve the situation, but there are many subtleties in the use of the theoretical results and there is clearly room for more study of the alkali opacities.…”

Section: Alkali Opacitymentioning

confidence: 99%

On the Cool Side: Modeling the Atmospheres of Brown Dwarfs and Giant Planets

Marley

Robinson

2015

Annu. Rev. Astron. Astrophys.

208

179

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The atmosphere of a brown dwarf or extrasolar giant planet controls the spectrum of radiation emitted by the object and regulates its cooling over time. While the study of these atmospheres has been informed by decades of experience modeling stellar and planetary atmospheres, the distinctive characteristics of these objects present unique challenges to forward modeling. In particular, complex chemistry arising from molecule-rich atmospheres, molecular opacity line lists (sometimes running to 10 billion absorption lines or more) multiple cloud-forming condensates, and disequilibrium chemical processes all combine to create a challenging task for any modeling effort. This review describes the process of incorporating these complexities into one-dimensional radiativeconvective equilibrium models of sub-stellar objects. We discuss the underlying mathematics as well as the techniques used to model the physics, chemistry, radiative transfer, and other processes relevant to understanding these atmospheres. The review focuses on the process of the creation of atmosphere models and briefly presents some comparisons of model predictions to data. Current challenges in the field and some comments on the future conclude the review.

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Section: Alkali Opacitymentioning

confidence: 99%

On the Cool Side: Modeling the Atmospheres of Brown Dwarfs and Giant Planets

Marley

Robinson

2015

Annu. Rev. Astron. Astrophys.

208

179

View full text Add to dashboard Cite

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“…Furthermore, because the shifts are also small, extremely good stability is required to make an accurate measurement of the dependence of shift on broadening, a process that requires measuring the wavelength of the line over a range of gas densities. Recently published experimental measurements for broadening by H 2 concerns neutral Na perturbed by H 2 (Allard et al 2012b). …”

Section: Spectral Line Parametersmentioning

confidence: 99%

K–H₂line shapes for the spectra of cool brown dwarfs

Allard

Spiegelman

Kielkopf

2016

A&A

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124

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Observations of cooler and cooler brown dwarfs show that the contribution from broadening at many bars pressure is becoming important. The opacity in the red optical to near-IR region under these conditions is dominated by the extremely pressure-broadened wings of the alkali resonance lines, in particular, the K I resonance doublet at 0.77 µm. Collisions with H 2 are preponderant in brown dwarf atmospheres at an effective temperature of about 1000 K; the H 2 perturber densities reach several 10 19 even in Jupiter-mass planets and exceed 10 20 for super-Jupiters and older Y dwarfs. As a consequence, it appears that when the far wing absorption due to alkali atoms in a dense H 2 atmosphere is significant, accurate pressure broadened profiles that are valid at high densities of H 2 should be incorporated into spectral models.

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“…Theoretical calculations of absorption profiles of Na and K perturbed by H 2 and He at high temperatures have been performed by Allard et al (2003Allard et al ( , 2012. Figure 19 shows a simulated visible spectrum of a gaseous, cloud-free exoplanet at spectral resolution R ∼ 200.…”

Section: The Visible Rangementioning

confidence: 99%

Spectroscopy of planetary atmospheres in our Galaxy

Tinetti

Encrenaz

Coustenis

2013

Astron Astrophys Rev

130

111

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About 20 years after the discovery of the first extrasolar planet, the number of planets known has grown by three orders of magnitude, and continues to increase at neck breaking pace. For most of these planets we have little information, except for the fact that they exist and possess an address in our Galaxy. For about one third of them, we know how much they weigh, their size and their orbital parameters. For less than 20, we start to have some clues about their atmospheric temperature and composition. How do we make progress from here?We are still far from the completion of a hypothetical Hertzsprung-Russell diagram for planets comparable to what we have for stars, and today we do not even know whether such classification will ever be possible or even meaningful for planetary objects. But one thing is clear: planetary parameters such as mass, radius and temperature alone do not explain the diversity revealed by current observations. The chemical composition of these planets is needed to trace back their formation history and evolution, as happened for the planets in our Solar System. As in situ measurements are and will remain off-limits for exoplanets, to study their chemical composition we will have to rely on remote sensing spectroscopic observations of their gaseous envelopes.

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Theoretical and laboratory spectra of sodium perturbed by molecular hydrogen

Cited by 28 publications

References 42 publications

On the Cool Side: Modeling the Atmospheres of Brown Dwarfs and Giant Planets

On the Cool Side: Modeling the Atmospheres of Brown Dwarfs and Giant Planets

K–H₂line shapes for the spectra of cool brown dwarfs

Spectroscopy of planetary atmospheres in our Galaxy

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Theoretical and laboratory spectra of sodium perturbed by molecular hydrogen

Cited by 28 publications

References 42 publications

On the Cool Side: Modeling the Atmospheres of Brown Dwarfs and Giant Planets

On the Cool Side: Modeling the Atmospheres of Brown Dwarfs and Giant Planets

K–H2line shapes for the spectra of cool brown dwarfs

Spectroscopy of planetary atmospheres in our Galaxy

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Product

Resources

About

K–H₂line shapes for the spectra of cool brown dwarfs