Jan. 16 () –
Observations with the James Webb and ALMA telescopes of the Large Magellanic Cloud have revealed hidden clusters of young stars that illustrate how some of the first stars in the universe were born.
Between 6 billion and 7 billion years ago, superstar clusters were the main form of star formation, producing hundreds of new stars each year. This type of star formation has been in decline, and super star clusters are very rarely found in our local Universe.
Currently, only two superstar clusters are known in the Milky Way and one in the Large Magellanic Cloud, all of them millions of years old. James Webb observations have now provided unequivocal evidence that the N79 region hosts a second superstar cluster in the Large Magellanic Cloud, just 100,000 years old. This discovery now allows astronomers witness the birth of a super star cluster in our neighboring galaxy.
The Large Magellanic Cloud, a satellite galaxy of our own Milky Way, It is located almost 160,000 light years from Earth. This relatively “close” distance and its frontal orientation to Earth make it an ideal laboratory for studying extragalactic star formation. JWST’s mid-infrared instrument (MIRI) observed 97 young stellar objects (YSOs) in the N79 region of the LMC, where the newly discovered star cluster, H72.97-69.39, is located.
The abundance of heavy elements in the Large Magellanic Cloud is half that of our Solar System, star formation conditions similar to those of 6-7 billion years ago. This offers astronomers an idea of how star formation may have taken place in the early days of the universe.
MIRI images show that the most massive YSOs gather near H72.97-69.39, and the less massive YSOs are distributed on the outskirts of N79, a process known as mass segregation. What was previously believed to be a single massive young star has now revealed itself as a cluster of five young starsrevealed by the precise images of the James Webb Space Telescope. One of the five young stars is more than 500,000 times more luminous than the Sun, with more than 1,550 young stars around it, as revealed by James Webb’s near-infrared camera (NIRCam).
ALMA (Atacama Large Millimeter/submillimeter Array) has made important contributions to the study of YSOs in the Large Magellanic Cloud, particularly in the N79 region. Previous ALMA observations of this region revealed two colliding one-parsec-long filaments of dust and gas. At their collision point is the superstar cluster H72.97-69.39, home to the most luminous protostar identified by JWST. Colliding filaments of molecular gas could be the catalyst needed to create a superstar cluster, and ALMA observations provide crucial context for understanding the large-scale environment in which these YSOs are forming.
This multi-wavelength investigation, combining data from JWST and ALMA, allowed astronomers to study the relationship between large-scale molecular cloud structures and the birth of protostars and clusters, reports in a statement the NRAO (National Radio Astronomy Observatory).
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