Water
is a ubiquitous substance in the universe, not only appearing as a liquid on
Earth but also frozen ice on distant planets, comets, and in the depths of interstellar
space. How much water is present during
the formation of star systems, however, is a question left unanswered due to
challenges of measuring vapor content in regions of energetic, often violent star
birth. However, by directing their
observations toward a much calmer, nebulous area of star formation, a team lead
by Professor Paola Caselli of the University of Leeds has recently determined
the quantity of water to be on the order of 2,000 times the volume of Earth’s
oceans.
Caselli’s
team studied a cloud, dubbed Lynds 1544 in the constellation Taurus, which is a
pre-stellar core, or a collection of gas and dust on the verge of collapsing
into an infant star. Using the Herschel
Space Observatory, a powerful telescope orbiting the earth, Caselli and her
team were able to directly observe water vapor to determine its combined mass. Their results indicate that there is far more
water in early star systems than previously expected, a significant finding
which helps shape our understanding of juvenile solar systems.
“I
am passionate about understanding our origins, which is why I have been
studying for many years dark clouds, where stars and planets form,” said Prof.
Caselli of the University of Leeds in West Yorkshire, England. “These particular clouds are the ideal
objects where to focus our attention if we want to unveil the initial
conditions of the whole process of star and planet formation.”
Unlike
young star systems which are subject to solar winds, stellar jets, and other astounding
displays of energy, Lynds 1544 is a relatively peaceful gas cloud with the
potential to collapse into a Sun-like star.
Already, the drift of the water vapor as observed by the Hershel
Observatory indicates that the cloud is gradually undergoing gravitational
collapse, in which material is slowly flowing toward the center where a star is
likely to be born.
While
the water in pre-stellar cores is typically frozen in ice, which makes it hard
to detect, the water content in L1544 is excited by passing cosmic rays, or
bands of energetic particles which, when absorbed by hydrogen molecules, can
help evaporate ice crystals. In this
case the water is made observable in the form of energized vapor. “This is an important result because it is
the first time that we have been able to measure water vapor in a pre-stellar
core,” Caselli commented. “We now know
the initial reservoir, or budget of water, at the dawn of a new solar-type
system.”
Water is a
crucial ingredient in the formation and preservation of life as we know it on
Earth. Therefore, knowing how much water
is present during the formation of stars and planets is key to understanding
the processes which made life possible in our solar system. The team’s next step is to perform similar
observations on other nebulous clouds in the galaxy to study how different
environments affect the chemistry of water, as understanding these dynamics may
unveil clues as to the origins of our own solar system or even the planet Earth
itself.
“I only hope
that people will wonder a little bit more about our wonderful Universe,” said
Caselli, “and how lucky we are to be here.”
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