ESA Hubble Science Release | 2019 Sep 11
With data from the NASA/ESA Hubble Space Telescope, water vapour has been detected in the atmosphere of a super-Earth within the habitable zone by University College London (UCL) researchers in a world first. K2-18b, which is eight times the mass of Earth, is now the only planet orbiting a star outside the Solar System, or exoplanet, known to have both water and temperatures that could support life. ...
The team used archive data from 2016 and 2017 captured by the NASA/ESA Hubble Space Telescope and developed open-source algorithms to analyse the starlight filtered through K2-18b’s atmosphere [1]. The results revealed the molecular signature of water vapour, also indicating the presence of hydrogen and helium in the planet’s atmosphere.
The authors believe that other molecules, including nitrogen and methane, may be present but they remain undetectable with current observations. Further studies are required to estimate cloud coverage and the percentage of atmospheric water present.
The planet orbits the cool dwarf star K2-18, which is 110 light years from Earth in the constellation of Leo. Given the high level of activity of its red dwarf star, K2-18b may be more hostile than Earth and is likely to be exposed to more radiation.
Hubble Finds Water Vapor on Habitable-Zone Exoplanet
NASA | GSFC | Hubble | 2019 Sep 11
First Water Detected on Potentially 'Habitable' Planet
University College, London | 2019 Sep11
Water Vapour in the Atmosphere of the Habitable-Zone Eight Earth-Mass Planet K2-18 b ~ Angelos Tsiaras et al
- Nature Astronomy (online 11 Sep 2019) DOI: 10.1038/s41550-019-0878-9
Water Detected on an Exoplanet in Its Star's Habitable Zone
University of Montreal | 2019 Sep 11
An international study lead by Université de Montréal astronomer Björn Benneke has detected water vapour on the planet K2-18b; this represents a major discovery in the search of alien life.
Ever since the discovery of the first exoplanet in the 1990s, astronomers have made steady progress towards finding and probing planets located in the habitable zone of their stars, where conditions can lead to the formation of liquid water and the proliferation of life.
Results from the Kepler satellite mission, which discovered nearly 2/3 of all known exoplanets to date, indicate that 5 to 20% of Earths and super-Earths are located in the habitable zone of their stars. However, despite this abundance, probing the conditions and atmospheric properties on any of these habitable zone planets is extremely difficult and has remained elusive… until now.
A new study by Professor Björn Benneke of the Institute for Research on Exoplanets at the Université de Montréal, his doctoral student Caroline Piaulet and several of their collaborators reports the detection of water vapour and perhaps even liquid water clouds in the atmosphere of the planet K2-18b. ...
Water Vapor on the Habitable-Zone Exoplanet K2-18b ~ Björn Benneke et al
- arXiv.org > astro-ph > arXiv:1909.04642 > 10 Sep 2019
Two Super-Earths around Star K2-18