Large water reservoirs at the dawn of stellar birth

Large water reservoirs at the dawn of stellar birth 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. Water, essential to life on Earth, has previously been detected outside of our Solar System as gas and ice coated onto tiny dust grains near sites of active star formation, and in proto-planetary discs capable of forming alien planetary systems. The new Herschel observations of a cold pre-stellar core in the constellation of Taurus known as Lynds 1544 are the first detection of water vapour in a molecular cloud on the verge of star formation. More than 2000 Earth oceans-worth of water vapour were detected, liberated from icy dust grains by high-energy cosmic rays passing through the cloud. "To produce that amount of vapour, 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.