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Over the last ten years, both space and ground observations have shown that H2O is the most abundant molecular species, after hydrogen, in atmospheres of hot, gaseous extrasolar planets. Being the main molecular carrier of oxygen, H2O is a tracer of origin and mechanisms of evolution of the planets.
For temperate terrestrial planets, the presence of H2O is of great importance as an indicator of housing conditions. Being small and relatively cold, these planets and their atmospheres are the most difficult to observe. As a result, no atmospheric spectral signature has been detected to date. The super-earths – planets lighter than ten M⊕ – around more recent type stars can provide our first opportunity to study by spectroscopy the characteristics of such planets, these being best suited to transit observations. We report here the detection of an H2O spectroscopic signature in the atmosphere of the "planet" – a planet of eight M⊕ in the habitable zone of a dwarf M – with a high statistical confidence (ADI = 5.0, 3 , 6σ).
In addition, the derived average molecular weight suggests an atmosphere still containing hydrogen. The observations were recorded with the Hubble Space Telescope / WFC3 camera and analyzed with our dedicated algorithms, available to the public. While the relevance of M-dwarfs to host habitable worlds is still under discussion, planet offers an unprecedented opportunity to better understand the composition and climate of living space planets.
Angelos Tsiaras, Ingo P. Waldmann, Giovanna Tinetti, Jonathan Tennyson, Sergey N. Yurchenko
(Submitted on Sept. 11, 2019)
Comments: Published in Nature Astronomy
Topics: Earth and planetary astrophysics (astro-ph.EP)
DOI: 10.1038 / s41550-019-0878-9
Cite as follows: arXiv: 1909.05218 [astro-ph.EP] (or arXiv: 1909.05218v1 [astro-ph.EP] for this version)
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From: Angelos Tsiaras
[v1] Wednesday, 11 September 2019 17:17:51 UTC (7,756 KB)
https://arxiv.org/abs/1909.05218
astrobiology
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