A NASA satellite has discovered water ejected from a fading star in the Leo constellation. Does it vaporize the comets and planets that surround it?
Avi Blizovsky
A red giant in its dying stages looks as if it is evaporating water, raising the possibility that there is, or at least was, another solar system that contains water - an important ingredient for life. This is what astronomers reported on Wednesday.
A carbon-rich star was not expected to contain a significant amount of water, but a NASA satellite used as a radio observatory discovered a large concentration of water evaporating around the star. The most likely possibility is that the water evaporates from the surface of comets falling into the surface of the star. says researcher Gary Melnick.
Several hundred billion comets are at the edge of the solar system of each Sun-like star, just the amount necessary to produce such a concentration of evaporating water, Melnick and his colleagues said.
Although the amount seems enormous, the mass of the water is similar to that found in the comets of the Kuiper belt, ice fragments that have been beyond the orbit of Neptune since the early days of the solar system.
From time to time a comet reaches the Sun and begins to evaporate, says research team member Sabic Ford. But CW Leonis - the star where the water was discovered, "is many times bigger and brighter than the Sun, whose comets begin to evaporate already from a distance similar to that of the distance from the Sun to the Kuiper belt.
CW Leonis is 500 light-years from Earth in the constellation Leo. Astronomers believe that the gas giant is shedding its outer layer, which will turn into a planetary nebula within a few tens of thousands of years.
"We think we are witnessing a certain type of apocalypse that will eventually occur in the solar system as well.: says David Neufeld, who helped decipher the information from the Submillimeter Wave Astronomy Satellite, which has been studying the universe in search of water for over two years.
In about six billion years, the Sun will begin to use up its hydrogen fuel supply and expand into a red giant like CW Leonis, swallowing up the planets. "Even Pluto will evaporate and be left with bare, boiling rock." says Neufeld.
According to the observations, there are at least sixty planetary systems similar to ours. But the composition of the ingredients remains a mystery. The new findings increase the hypothesis that many of them contain large reservoirs of water, like many bodies in our solar system.
Melnik, an astronomer at the Harvard-Smithsonian Center for Astrophysics, and his colleagues reported their findings on July 12 in the journal Nature.
