Using the Atacama Large Millimetre/submillimetre Array, astronomers observed the birth of
a massive star within a dark cloud core, revealing in superb detail the filamentary network of dust and gas flowing into the central compact region of the
Scientists have observed in unprecedented detail the birth of a massive star within a dark cloud core about 10,000 light years from Earth.
The 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 – published in the journal Astronomy and Astrophysics –
reveal how matter is being dragged into the center of the huge gaseous cloud by the gravitational pull of the forming star – or stars – along a number of dense
threads or filaments.
“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!
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 center. 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 center to form one or more massive stars.
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.
“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 center 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 center 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 generated.”
Dr Peretto added: “We managed to get these very detailed observations using only a fraction of ALMA’s ultimate potential. ALMA
will definitely revolutionize our knowledge of star formation, solving some current problems, and certainly raising new ones.”
- Astronomers use the expression “massive stars” to mean those with roughly ten or more times the mass of the Sun. It refers to the star’s mass, not itssize.
- This star formation region is forming many stars. The 500 solar mass core is the most massive of several.
Peretto, et al., “Global collapse of molecular clouds as a formation mechanism for the most massive stars,” A&A, Volume 555, A112, July 2013;
Source: University of Manchester
Images: David A. Hardy; N. Peretto, et al., A&A 555, A112 (2013)