Water spotted in planet-forming part of space

Astronomers have spotted water in space near a star similar to the Sun, potentially giving a glimpse into conditions that supported formation of planets like Earth.

The young sun ‘HL Tauri’ is located about 450 light-years away in the constellation Taurus. Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, teams have observed water vapour surrounding the star ‘HL Tauri’, located about 450 light-years away in the constellation Taurus.

It’s estimated to be about 3 times the amount of water on Earth, occupying a gap within a larger disc full of gas and dust, which are the key ingredients for planet formation.

The discovery team predicts an ocean-covered planet might be in the works.

“I had never imagined that we could capture an image of oceans of water vapour in the same region where a planet is likely forming,” says the study’s leader Stefano Facchini, an astronomer at Milan University.

As dust and gas collide, they may eventually form into a planet in orbit around HL Tauri. Facchini’s team says the presence of water nearby might influence that emergent planet’s chemical composition, though it takes millions of years for a planet the size of the Earth to reach the final stages of development.

“Directly measuring the amount of water vapour where planets are forming takes us a step closer to understanding how easy it could be to make worlds with oceans,” says Anita Richards, an astronomer at the University of Manchester who contributed to the study.

She supported the research team to verify data obtained from ALMA, which used a highly sensitive suite of ‘Band 5’ receivers to detect distant water. These receivers in the middle of the ultra-dry Atacama Desert 500m above sea level can separate the distinct but faint radio signals of water at wavelengths of 1.4-1.8mm from the ‘noise’ of vapour swirling in Earth’s own atmosphere.

“This sort of observation needs the driest possible conditions and could only be made in such detail using the ALMA array in Chile,” says Richards.

The research has been published in the journal Nature Astronomy.

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