A comparison of exoplanet spectroscopic retrieval tools

被引:60
作者
Barstow, Joanna K. [1 ]
Changeat, Quentin [1 ]
Garland, Ryan [2 ]
Line, Michael R. [3 ]
Rocchetto, Marco [1 ]
Waldmann, Ingo P. [1 ]
机构
[1] UCL, Dept Phys & Astmn, Gower St, London WC1E 6BT, England
[2] Univ Oxford, Atmospher Ocean & Planetary Phys, Clarendon Lab, Keble Rd, Oxford OX1 3PU, England
[3] Arizona State Univ, Sch Earth & Space Explorat, POB 871404, Tempe, AZ 85281 USA
基金
英国科学技术设施理事会; 欧洲研究理事会;
关键词
radiative transfer; methods: data analysis; methods: statistical; techniques: spectroscopic; planets and satellites: atmospheres; COLLISION-INDUCED ABSORPTION; LINE LISTS; H-2; PAIRS; ATMOSPHERE; WATER; TEMPERATURE; EMISSION; CLOUDS; CLEAR;
D O I
10.1093/mnras/staa548
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Over the last several years, spectroscopic observations of transiting exoplanets have begun to uncover information about their atmospheres, including atmospheric composition and indications of the presence of clouds and hazes. Spectral retrieval is the leading technique for interpretation of transmission spectra and is employed by several teams using a variety of forward models and parameter estimation algorithms. However, different model suites have mostly been used in isolation and so it is unknown whether the results from each are comparable. As we approach the launch of the James Webb Space Telescope, we anticipate advances in wavelength coverage, precision, and resolution of transit spectroscopic data, so it is important that the tools that will be used to interpret these information-rich spectra are validated. To this end, we present an intermodel comparison of three retrieval suites: TAUREX, NEMESIS, and CHIMERA. We demonstrate that the forward model spectra are in good agreement (residual deviations on the order of 20-40 ppm), and discuss the results of cross-retrievals among the three tools. Generally, the constraints from the cross-retrievals are consistent with each other and with input values to within 1 sigma. However, for high precision scenarios with error envelopes of order 30 ppm, subtle differences in the simulated spectra result in discrepancies between the different retrieval suites, and inaccuracies in retrieved values of several sigma. This can be considered analogous to substantial systematic/astrophysical noise in a real observation, or errors/omissions in a forward model such as molecular line list incompleteness or missing absorbers.
引用
收藏
页码:4884 / 4909
页数:26
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