James Webb space telescope detects water vapour in planetary system

Development indicates that the planets forming around it might be able to support life one day

A water vapour signature was detected by the Webb telescope fewer than 160 million km away from the star. Photo: Nasa
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Water vapour detected close to a star about 370 light years away could offer signs that a planetary system named PDS 70 may one day support life.

For the first time, measurements have been taken by high-resolution images extracted from Nasa’s James Webb space telescope that conducts infrared astronomy.

The star at the centre of the system is about 5.4 million years old and is circled by two giant gas planets, with a third possibly in formation.

A water vapour signature was detected by the Webb telescope fewer than 160 million km away from the star, a similar distance from the Earth to the Sun.

It is the first time water has been detected among disks of gas and dust that eventually create stars and planets, and was only possible because of the unique capabilities of the James Webb telescope to scan space.

Astronomers studying the data, published in the journal Nature, previously believed water vapour would not survive in a star of that age due to stellar radiation. They also believed that any planets formed would be dry.

Further research is under way to see how rocky planets with water, similar to Earth, could be formed.

“We’ve seen water in other disks, but not so close in and in a system where planets are currently assembling,” said lead author Giulia Perotti of the Max Planck Institute for Astronomy in Heidelberg, Germany, in comments carried by Nasa's online blog.

“We couldn’t make this type of measurement before Webb.”

The institute's director Thomas Henning, one of the report's authors, said the discovery was “extremely exciting as it probes the region where rocky planets similar to Earth typically form”.

Mr Henning is co-principal investigator of Webb’s Mid-Infrared Instrument (Miri), which made the detection, and the principal investigator of the Miri Mid-Infrared Disk Survey programme that took the data.

The super telescope has also pictured two actively young stars about 1,470 light years away.

In a striking pink-coloured smear at its centre, the collection of stars named Herbig-Haro 46/47 can be seen, thanks to the telescope's infrared sensors, otherwise the images would only be in black and white.

The images from the baby stars reveal a wealth of data that could uncover the secrets of the cosmos for astronomers and shed more light on how stars are formed.

Updated: July 28, 2023, 11:53 AM