The European Space Agency's Herschel space observatory has discovered enough water vapor to fill Earth's oceans more than 2000 times over, in a gas and dust cloud that is on the verge of collapsing into a new Sun-like star. Stars form within cold, dark clouds of gas and dust -- 'pre-stellar cores' -- that contain all the ingredients to make solar systems like our own.
"To produce that amount of vapor, there must be a lot of water ice in the cloud, more than three million frozen Earth oceans' worth," says Paola Caselli from the University of Leeds, UK, lead author of the paper reporting the results in Astrophysical Journal Letters.
"Before our observations, the understanding was that all the water was frozen onto dust grains because it was too cold to be in the gas phase and so we could not measure it. Now we will need to review our understanding of the chemical processes in this dense region and, in particular, the importance of cosmic rays to maintain some amount of water vapor."
The observations also revealed that the water molecules are flowing towards the heart of the cloud where a new star will probably form, indicating that gravitational collapse has just started.* "There is absolutely no sign of stars in this dark cloud today, but by looking at the water molecules, we can see evidence of motion inside the region that can be understood as collapse of the whole cloud towards the center," says Dr Caselli.
"There is enough material to form a star at least as massive as our Sun, which means it could also be forming a planetary system, possibly one like ours."* Some of the water vapor detected in L1544 will go into forming the star, but the rest will be incorporated into the surrounding disc, providing a rich water reservoir to feed potential new planets.
The Daily Galaxy via European Space Agency (ESA)