Astronomers witness birth of Milky Way’s most massive star
Scientists have observed in
unprecedented detail the birth of a massive star within a dark cloud core about
10,000 light years from Earth.
impression of the forming massive star
(Credit: David A
Hardy / www.astroart.org)
The UK-led team used the new
ALMA (Atacama Large Millimetre/submillimetre Array) telescope in Chile – the
most powerful radio telescope in the world – to view the stellar womb which, at
500 times the mass of the Sun and many times more luminous, is the largest ever
seen in our galaxy.
The researchers say their
observations – to be published in the journal 'Astronomy and Astrophysics'
– reveal how matter is being dragged into the centre of the huge gaseous cloud
by the gravitational pull of the forming star – or stars – along a number of
dense threads or filaments. The result comes a few months after the telescope
was formally inaugurated in Chile.
“The remarkable observations from
ALMA allowed us to get the first really in-depth look at what was going on
within this cloud,” said lead author Dr Nicolas Peretto, from Cardiff
University. “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!
“Even though we already believed that
the region was a good candidate for being a massive star-forming cloud, we were
not expecting to find such a massive embryonic star at its centre. This cloud
is expected to form at least one star 100 times more massive than the Sun and
up to a million times brighter. Only about one in 10,000 of all the stars in
the Milky Way reach that kind of mass.”
Different theories exist as
to how these massive stars form but the team’s findings lend weight to the idea
that the entire cloud core begins to collapse
inwards, with material raining in towards the centre to form one or more
Co-author Professor Gary Fuller,
from The University of Manchester, said: "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.
infrared image of the cloud from the NASA Spitzer satellite showing the dark,
dense filaments which are feeding the central forming massive star
“Our observations reveal in superb
detail the filamentary network of dust and gas flowing into the central compact
region of the cloud and strongly support the theory of global collapse for the
formation of massive stars.”
The University of Manchester hosts
the Science and Technology Facilities Council (STFC)-funded support centre for
UK astronomers using ALMA, where the observations were processed.
Team member Dr Ana Duarte-Cabral,
from the Université de Bordeaux, said: “Matter is drawn into the centre of
the cloud from all directions but the filaments are the regions around the star
that contain the densest gas and dust and so these distinct patterns are
Peretto added: “We managed to get these very detailed observations using only a
fraction of ALMA’s ultimate potential. ALMA will definitely revolutionise our
knowledge of star formation, solving some current problems, and certainly
raising new ones.”
Access to ESO
telescopes including ALMA is made possible for UK astronomers by a subscription
paid for by STFC.
Additional information is available
from the University of Manchester
and ESO press releases.
A copy of the paper, entitled
‘Global collapse of molecular clouds as a formation mechanism for the most
massive stars,’ published in 'Astronomy & Astrophysics', is available.
The research team comprised of:
- N. Peretto
(CEA/AIM Paris Saclay, France; University of Cardiff, UK)
- G. A. Fuller
(University of Manchester, UK; Jodrell Bank Centre for Astrophysics and UK ALMA
Regional Centre Node)
- A. Duarte-Cabral (LAB, OASU, Université de Bordeaux,
- A. Avison (University of Manchester, UK; UK ALMA Regional Centre
- P. Hennebelle (CEA/AIM Paris Saclay, France)
- J. E. Pineda (University
of Manchester, UK; UK ALMA Regional Centre node; ESO, Garching, Germany)
André (CEA/AIM Paris Saclay, France)
- S. Bontemps (LAB, OASU, Université de Bordeaux, CNRS,
- F. Motte (CEA/AIM Paris Saclay, France)
- N. Schneider (LAB, OASU,
Université de Bordeaux, CNRS, France)
- S. Molinari (INAF, Rome, Italy)
Broader UK involvement in ALMA
includes STFC’s Rutherford Appleton Laboratory and UK Astronomy Technology
Centre, the Cavendish Laboratory at the University of Cambridge, the University
of Manchester and the University of Kent, all of whom played key roles in the
design and construction of ALMA.
The University of Manchester
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