 ?> -REx. II. RETRIEVAL OF EMISSION SPECTRA

By Ingo P. Waldmann, Marco Rocchetto, Giovanna Tinetti, E. J. Barton, Sergei N. Yurchenko, Jonathan Tennyson. 2015

84 citations recorded by the source corpus.

 ?> -REx (Tau Retrieval of Exoplanets) is a novel, fully Bayesian atmospheric retrieval code custom built for extrasolar atmospheres. In Waldmann et al., the transmission spectroscopic case was introduced, and here we present the emission spectroscopy spectral retrieval for the  ?> -REx framework. Compared to transmission spectroscopy, the emission case is often significantly more degenerate due to the need to retrieve the full atmospheric temperature–pressure (TP) profile. This is particularly true in the case of current measurements of exoplanetary atmospheres, which are either of low signal-to-noise, low spectral resolution, or both. We present a new way of combining two existing approaches to the modeling of the said TP profile: (1) the parametric profile, where the atmospheric TP structure is analytically approximated by a few model parameters, (2) the layer-by-layer approach, where individual atmospheric layers are modeled. Both of these approaches have distinct advantages and disadvantages in terms of convergence properties and potential model biases. The  ?> -REx hybrid model presented here is a new two-stage TP profile retrieval, which combines the robustness of the analytic solution with the accuracy of the layer-by-layer approach. The retrieval process is demonstrated using simulations of the hot-Jupiter WASP-76b and the hot-super-Earth 55 Cnc e as well as the secondary eclipse measurements of HD 189733b.

Subfields: Atomic and Molecular Physics, and Optics, Spectroscopy, Statistical and Nonlinear Physics

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Citations in the corpus

The 2020 release of the ExoMol database: Molecular line lists for exoplanet and other hot atmospheres (2020, methodology): “REx [13, 14].”
A NEW APPROACH TO ANALYZING HST SPATIAL SCANS: THE TRANSMISSION SPECTRUM OF HD 209458 b (2015, methodology): “We used the nested sampling algorithm implemented in T -REx (Waldmann et al. 2015a,b) to fully explore the parameter space and find the best fit to the WFC3 spectrum.”
A Population Study of Gaseous Exoplanets (2017, methodology): “The observed spectra were fitted using the Bayesian atmospheric retrieval framework T -REx (Waldmann et al. 2015a,b).”
Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e (2020, methodology): “…solution (or a modification of it) by Guillot (2010); Parmentier & Guillot (2014) is commonly used, for example in Line et al. (2012, 2013a,b, 2014b), Benneke & Seager (2012), Waldmann et al. (2015), Rocchetto et al. (2016), Kreidberg et al. (2018), Brogi & Line (2019), Mollière et al. (2019).”
NO THERMAL INVERSION AND A SOLAR WATER ABUNDANCE FOR THE HOT JUPITER HD 209458B FROM HST/WFC3 SPECTROSCOPY (2016, methodology): “…to identify which molecules are actually “detected” in this spectrum, we perform a standard nested Bayesian model comparison using the full Bayesian evidence calculation from pymultinest (Trotta 2008; Benneke & Seager 2013; Swain, Line & Deroo 2014; Waldmann et al. 2015a,b; Kreidberg et al. 2015).”
DETECTION OF AN ATMOSPHERE AROUND THE SUPER-EARTH 55 CANCRI E (2015, methodology): “Atmospheric retrieval In order to fit the WFC3 spectrum we use T -REx (Waldmann et al. 2015b,a), a Bayesian spectral retrieval that fully maps the parameter space through the nested sampling algorithm.”
Exoplanetary Atmospheres: Key Insights, Challenges, and Prospects (2019, background): “ances are obtained from the following sources: Jupiter and Saturn (9, 281, 79), Neptune (121), and Uranus (254). The exoplanet H O abundances are from various works: HD 209458b (206, 151), HD 189733b (206, 278), WASP12b (206), WASP-43b (132), WASP-33b (102), TrES-3 (148), GJ 436b (187), HAT-P-26b (2”
HD 209458b in new light: evidence of nitrogen chemistry, patchy clouds and sub-solar water (2017, methodology): “…atmospheres in transmission (Benneke & Seager 2012, 2013; Benneke 2015; Waldmann et al. 2015a; Line & Parmentier 2016), thermal emission (Lee et al. 2012; Barstow et al. 2013; Line et al. 2013, 2016; Waldmann et al. 2015b) and reflected light (Lee et al. 2013; Lupu et al. 2016; Lavie et al. 2016).”