arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 2110.01271astro-ph.EPastro-ph.IM
收藏

由TauREx 3.1启用的系外行星大气化学模型的比较

A comparison of chemical models of exoplanet atmospheres enabled by TauREx 3.1

Ahmed F. Al-Refaie, Quentin. Changeat, Olivia Venot, Ingo P. Waldmann, Giovanna Tinetti

摘要:

热化学平衡是目前系外行星反演中最常用的假设之一。随着詹姆斯韦伯太空望远镜(JWST)和Ariel发射的临近,评估将自洽化学应用于光谱检索时所做的潜在偏差和假设至关重要。在这里,我们使用TauREx 3.1的灵活性来交叉比较三种最先进的化学平衡代码:ACE,FastChem和GGchem。我们模拟的JWST光谱ACE,FastChem,GGchem和GGchem+缩合只包含C,H,O,N元素和光谱FastChem,GGchem和GGchem+缩合更广泛的元素范围内给出7个模拟的JWST光谱,然后交叉检索,共49检索。我们的分析表明,相似的,所有的化学代码检索正确的参数,以<1%的真理。然而,检索,其中包含的元素不匹配的真相,参数,如金属丰度偏离20%,同时保持极低的不确定性<1%,给出虚假的信心。这一点对于JWST和Ariel的未来分析至关重要,强调不采用适当假设(缺失物种,固定元素比例,冷凝)的自洽化学方案有可能导致自信的偏差解释。自由化学检索采用参数描述的化学配置文件可以提供替代无偏的探索。

英文摘要:

Thermochemical equilibrium is one of the most commonly used assumptions in current exoplanet retrievals. As the James Webb Space Telescope (JWST) and Ariel launch draw near, assessing the underlying biases and assumptions made when applying self-consistent chemistry into spectral retrievals is crucial. Here we use the flexibility of TauREx 3.1 to cross-compare three state of the art chemical equilibrium codes: ACE, FastChem and GGchem. We simulate JWST spectra for ACE, FastChem, GGchem and GGchem+condensation containing only C, H, O, N elements and spectra for FastChem, GGchem and GGchem+condensation with a more extensive range of elements giving seven simulated JWST spectra in total and then cross-retrieve giving a total of 49 retrievals. Our analysis demonstrates that like-for-like, all chemical codes retrieve the correct parameters to <1% of the truth. However, retrievals, where the contained elements do not match the truth, parameters such as metallicity deviate by 20% while maintaining extremely low uncertainties <1% giving false confidence. This point is of major importance for future analyses on JWST and Ariel, highlighting that self-consistent chemical scheme that do not employ the proper assumptions (missing species, fixed elemental ratios, condensation) are at risk of confidently biasing interpretations. Free chemistry retrievals employing parametric descriptions of the chemical profiles can provide alternative unbiased explorations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑