HELIOS: An Open-Source, GPU-Accelerated Radiative Transfer Code For Self-Consistent Exoplanetary Atmospheres
Matej Malik, Luc Grosheintz, João M. Mendonça, Simon L. Grimm, Baptiste Lavie, Daniel Kitzmann, Shang-Min Tsai, Adam Burrows, Laura Kreidberg, Megan Bedell, Jacob L. Bean, Kevin B. Stevenson, Kevin Heng
(Submitted on 17 Jun 2016)
We present the open-source radiative transfer code named HELIOS, which is constructed for studying exoplanetary atmospheres. In its initial version, the model atmospheres of HELIOS are one-dimensional and plane-parallel, and the equation of radiative transfer is solved in the two-stream approximation with non-isotropic scattering. The opacities are computed with the opacity calculator HELIOS-K and converted to k-distribution tables by weighing the molecular abundances with analytical chemistry formulae. We validate HELIOS by comparing a model of GJ 1214b to that computed using COOLTLUSTY and from the work of Miller-Ricci & Fortney, and by performing several tests, where we find: model atmospheres with single-temperature layers struggle to converge to radiative equilibrium; k-distribution tables constructed with < 0.01 cm-1 resolution in the opacity function (< 1000 points per wavenumber bin) may result in errors > 1-10% in the synthetic spectra; and a diffusivity factor of 2 approximates well the exact radiative transfer solution in the limit of pure absorption. We construct “null-hypothesis” models (chemical equilibrium, radiative equilibrium and solar element abundances) for 6 hot Jupiters. We find that the dayside emission spectra of HD 189733b and WASP-43b are consistent with the null hypothesis, while it consistently under-predicts the observed fluxes of WASP-8b, WASP-12b, WASP-14b and WASP-33b. We demonstrate that our results are somewhat insensitive to the choice of stellar models (blackbody, Kurucz or PHOENIX) and metallicity, but are strongly affected by higher carbon-to-oxygen ratios. The code is publicly available as part of the Exoclimes Simulation Platform (ESP; www.exoclime.net).
Comments: 23 pages, 15 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph)
Cite as: arXiv:1606.05474 [astro-ph.EP]
(or arXiv:1606.05474v1 [astro-ph.EP] for this version)
Submission history
From: Matej Malik
[v1] Fri, 17 Jun 2016 11:01:09 GMT (2820kb,D)
http://arxiv.org/abs/1606.05474
