Published: Fri, September 13, 2019
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Scientists find water on potentially habitable planet, World News & Top Stories

Scientists find water on potentially habitable planet, World News & Top Stories

Astronomers found water vapour in the atmosphere of a potentially inhabitable planet which is twice the size and eight times the mass of Earth. The total amount of solar irradiation that Earth and K2-18b receive is approximately equal.

Astronomers now believe they've detected liquid water in the atmosphere of a planet orbiting within the habitable zone of its parent star. Getting to know K2-18b a bit better, she said, "will be important for understanding the potential habitability of smaller "Earth-sized" planets".

For the first time, researchers have found a planet outside of our solar system that has water on it. "This is not only because super-Earths like K2-18b are the most common planets in our Galaxy, but also because red dwarfs - stars smaller than our Sun - are the most common stars".

The team used archive data from 2016 and 2017 captured by the ESA/NASA Hubble Space Telescope and developed open-source algorithms to analyse the starlight filtered through K2-18b's atmosphere.

Because light from the K2-18b's star takes a century to reach the Earth, to travel over there would be "impossible", he said. These worlds include broiling hot versions of our own Jupiter, Saturn and Neptune, and steamy Super-Earths that are more water than rock. "While not a true Earth-analogue due to its size, this bodes well for our exploration of small planets", Josh Lothringer, who studies exoplanet atmospheres at Johns Hopkins University in the United States, said on Twitter.

The study's lead author, Greek-born Angelos Tsiaras, presented the exciting findings in the journal Nature Astronomy.

However, the discovery brings astronomers closer to answering the fundamental question of how unique Earth is in the universe, the scientists said. The results revealed the molecular signature of water vapor, also indicating the presence of hydrogen and helium in the planet's atmosphere.

Ultimately K2-18B might be hostile to life since it has been exposed to high-energy radiation.


Björn Benneke (University of Montreal) led a team in applying for time on the Hubble Space Telescope, observing the planet as it crossed the face of its star.

Further studies are required to estimate cloud coverage and the percentage of atmospheric water present, the researchers said.

In addition to water, Hubble also detected traces of hydrogen, an observation that intrigued Tom Louden, a physicist at the University of Warwick and an expert on exoplanetary atmospheres.

K2-18b orbits a red dwarf star about 110 light years distant - a million billion kilometres - in the Leo constellation of the Milky Way, and is probably bombarded by more destructive radiation than Earth.

That's largely because the researchers are taking a transmission spectrum of the planet as it passes in front of its host star - that is, they're looking at the star's light as it passes through a thin sliver of the planet's atmosphere.

"Our discovery makes K2-18 b one of the most interesting targets for future study", said Giovanna Tinetti, study co-author and principal investigator for ARIEL.

So the only option is to wait for the next generation of space telescopes to be launched in the 2020s and to look for gasses in the planet's atmosphere that could only be produced by living organisms, the report in BBC News had stated quoting UCL's Dr Ingo Waldmann.

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