NASA's Spitzer Space Telescope has detected enough water vapor to fill the oceans on Earth five times inside the collapsing nest of a forming star system. Astronomers say the water vapor is pouring down from the system's natal cloud and smacking into a dusty disk where planets are thought to form.
The observations provide the first direct look at how water, an essential ingredient for life as we know it, begins to make its way into planets, possibly even rocky ones like our own.
"For the first time, we are seeing water being delivered to the region where planets will most likely form," said Dan Watson of the University of Rochester, N.Y. Watson is the lead author of a paper about this "steamy" young star system, appearing in the Aug. 30 issue of Nature.
The star system, called NGC 1333-IRAS 4B, is still growing inside a cool cocoon of gas and dust. Within this cocoon, circling around the embryonic star, is a burgeoning, warm disk of planet-forming materials. The new Spitzer data indicate that ice from the stellar embryo's outer cocoon is falling toward the forming star and vaporizing as it hits the disk.
"On Earth, water arrived in the form of icy asteroids and comets. Water also exists mostly as ice in the dense clouds that form stars," said Watson. "Now we've seen that water, falling as ice from a young star system's envelope to its disk, actually vaporizes on arrival. This water vapor will later freeze again into asteroids and comets."
