arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1708.04239astro-ph.EP
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用JWST观测已知温带地球大小行星的大气

Observing the Atmospheres of Known Temperate Earth-sized Planets with JWST

Caroline V. Morley, Laura Kreidberg, Zafar Rustamkulov, Tyler Robinson, Jonathan J. Fortney

摘要:

最近在附近的晚M矮星周围发现了九颗凌日地球大小的行星,包括TRAPPIST-1行星和MEarth调查发现的两颗行星GJ 1132 b和LHS 1140 b。这些行星是已知最小的行星,可能有适合JWST探测的大气层。我们提出了模型的热发射和传输光谱,每个行星,不同的成分和表面压力的大气。我们的基础上的地球,土卫六和金星的元素组成和计算的分子组成假设化学平衡,这可以强烈依赖于温度。热发射光谱和透射光谱都对大气成分敏感;热发射光谱对表面压力和温度敏感。我们用JWST预测了每个行星大气的可观测性。GJ 1132 b和TRAPPIST-1b是JWST/MIRI发射光谱的优秀目标,需要不到10次日食观测。TRAPPIST-1c的发射测光需要5-15次日食; LHS 1140 b和TRAPPIST-1d、TRAPPIST-1 e和TRAPPIST-1f,可能有表面液态水,可以通过测光获得。九颗行星中有七颗是JWST透射光谱测量的有力候选者,尽管所需的凌日次数在很大程度上取决于行星的实际质量。使用测得的质量,不到20个凌日需要5西格玛检测GJ 1132 b和6个TRAPPIST-1行星的光谱特征。专门测量这九颗行星的大气层的活动将使我们能够第一次探测我们太阳系以外的陆地行星大气的形成和演变过程。

英文摘要:

Nine transiting Earth-sized planets have recently been discovered around nearby late M dwarfs, including the TRAPPIST-1 planets and two planets discovered by the MEarth survey, GJ 1132b and LHS 1140b. These planets are the smallest known planets that may have atmospheres amenable to detection with JWST. We present model thermal emission and transmission spectra for each planet, varying composition and surface pressure of the atmosphere. We base elemental compositions on those of Earth, Titan, and Venus and calculate the molecular compositions assuming chemical equilibrium, which can strongly depend on temperature. Both thermal emission and transmission spectra are sensitive to the atmospheric composition; thermal emission spectra are sensitive to surface pressure and temperature. We predict the observability of each planet's atmosphere with JWST. GJ 1132b and TRAPPIST-1b are excellent targets for emission spectroscopy with JWST/MIRI, requiring fewer than 10 eclipse observations. Emission photometry for TRAPPIST-1c requires 5-15 eclipses; LHS 1140b and TRAPPIST-1d, TRAPPIST-1e, and TRAPPIST-1f, which could possibly have surface liquid water, may be accessible with photometry. Seven of the nine planets are strong candidates for transmission spectroscopy measurements with JWST, though the number of transits required depends strongly on the planets' actual masses. Using the measured masses, fewer than 20 transits are required for a 5 sigma detection of spectral features for GJ 1132b and six of the TRAPPIST-1 planets. Dedicated campaigns to measure the atmospheres of these nine planets will allow us, for the first time, to probe formation and evolution processes of terrestrial planetary atmospheres beyond our solar system.

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。

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