Astronomers spot star embryo in largest ever galactic ‘womb’
July 10, 2013 | Raw Story | Agence France-Presse
Astronomers on Wednesday reported their best observation yet of a
massive star embryo growing within a dark cloud — the largest stellar
“womb” ever spotted in our Milky Way galaxy.
The star, which could grow to 100 times the mass of our Sun and up to
a million times brighter, was spotted by the most powerful radio
telescope on Earth — the ALMA international astronomy facility located
in Chile, according to a paper published in the journal Astronomy and
Astrophysics.
Astronomers hope its discovery, at a distance of some 11,000 light
years from Earth, will shed light on how these exceptionally massive
stars are formed, shrouded as they are in dust and mystery.
“Not only are these stars rare, but their births are extremely rapid
and childhood short, so finding such a massive object so early in its
evolution in our Galaxy is a spectacular result,” study co-author Gary
Fuller of the University of Manchester said in a statement issued by the
European Southern Observatory (ESO)
The most massive and brightest stars in the galaxy form within cool
and dark cloud cores, hungrily feeding on material being dragged inwards
by the embryo star’s gravitational pull.
This specific star is located in the Spitzer Dark Cloud, whose core has a mass about 500 times that of the Sun.
“This object is expected to form a star that is up to 100 times more
massive than the Sun. Only about one in ten thousand of all stars in the
Milky Way reach that kind of mass,” said study lead author Nicolas
Peretto of Cardiff University.
“The remarkable observations from ALMA allowed us to get the first
really in-depth look at what was going on within this cloud. We wanted
to see how monster stars form and grow, and we certainly achieved our
aim. One of the sources we have found is an absolute giant — the largest
protostellar core ever spotted in the Milky Way!”
According to the ESO, there are two theories on the formation of
massive stars, which have at least ten times the mass of our Sun.
The first theory suggests that parental dark clouds fragment,
creating several small cores that collapse and form stars. The other
sees the entire cloud collapse inwards, with material racing into its
centre to feed the star or stars growing there.
The new results support the second theory, said the statement.
“The ALMA observations reveal the spectacular details of the motions
of the filamentary network of dust and gas and show that a huge amount
of gas is flowing into a central compact region,” said team member Ana
Duarte Cabral from the Laboratoire d’Astrophysique in Bordeaux, France.
The find was made possible by the high sensitivity of the Atacama
Large Millimetre/submillimetre Array, located 5,000 meters (16,400 feet)
above sea level, deep in Chile’s Atacama Desert.
ALMA has 66 antennas exploring the universe via radio waves emitted
by galaxies, stars and other bodies not captured by optical and infrared
telescopes, which only receive light.
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