Most of the stars in the universe – including our life-giving Population 1, the main-sequence Sun, one of the more than 100 billion stars in the Milky Way, which formed approximately 4.6 billion years ago – are they formed a group of massive stars created from the violent gravitational collapse of matter within a region of a large molecular cloud. These clusters are the building blocks of galaxies, but their actual formation from these dense clouds is a mystery.
The outskirts of our galaxy, the Milky Way, are in orbit around 150 globular star clusters, among the oldest objects in the galaxy, formed about 11.5 billion years ago, 2.3 billion years after the Big Bang and shortly before the rate of cosmic star formation will peak. , 10 billion years ago, a period known as “cosmic noon”. A globular cluster could be the first place where intelligent life is identified in our galaxy, ”according to Rosanne DiStefano of the Harvard-Smithsonian Center for Astrophysics (CfA).
The stars in these ancient clusters contain fewer heavy elements needed to build planets, since those elements (such as iron and silicon) must be created in the younger generations of stars. Unlike DiStefano, some scientists have argued that this makes the 11-star globular cluster population less likely to harbor planets. Only one planet has been found in a globular cluster to date.
The image of the group G286.21 + 0.17, captured in the act of formation, is a mosaic of multiple wavelengths formed by more than 750 individual radio observations with the Atacama Large Millimeter / submillimeter Array (ALMA) and 9 infrared images of The NASA. / ESA’s Hubble Space Telescope. The cluster is located in the Carina region of our galaxy, about 8000 light years away.
ALMA reveals dense clouds made of molecular gas (purple ‘fireworks streamers’). The telescope observed the movements of the turbulent gas that falls into the cluster, forming dense cores that eventually create individual stars.
The stars in the image are revealed by their infrared light, as seen by Hubble, including a large group of stars emerging from one side of the cloud. The powerful winds and radiation from the most massive of these stars are blasting away the molecular clouds, leaving faint wisps of bright, hot dust (shown in yellow and red).
“This image shows stars in various stages of formation within this unique group,” said Yu Cheng of the University of Virginia in Charlottesville, Virginia, and lead author of two articles published in The Astrophysical Journal.
“Oldest objects in the universe”: Bubble clues solve the puzzle of globular galaxy clusters
Hubble revealed around a thousand newly formed stars with a wide range of masses. Furthermore, ALMA demonstrated that there is much more mass present in the dense gas that has yet to collapse. “Overall, the process can take at least a million years to complete,” added Cheng.
“This illustrates how dynamic and chaotic the process of star birth is,” said co-author Jonathan Tan of Chalmers University in Sweden and the University of Virginia and principal investigator on the project. “We see competing forces at work: the gravity and turbulence of the cloud on one side, and the stellar winds and radiation pressure of young stars on the other. This process sculpts the region. It is surprising to think that our own Sun and our planets were once part of such a cosmic dance. “
“ALMA’s phenomenal resolution and sensitivity are evident in this striking image of star formation,” said Joe Pesce, NSF Program Officer for NRAO / ALMA. “Combined with data from the Hubble Space Telescope, we can clearly see the power of multi-wavelength observations to help us understand these fundamental universal processes.”
Source: “Gas kinematics of the massive G286.21 + 0.17 protocol revealed by ALMA”, Yu Cheng et. al., The Astrophysical Journal. https://doi.org/10.3847/1538-4357/ab879f “Stellar Variability in a Massive Star Cluster in Formation”, Yu Cheng et. al., The Astrophysical Journal. https://doi.org/10.3847/1538-4357/ab93bc
The Daily Galaxy, Max Goldberg, through the National Radio Astronomy Observatory
The image at the top of the page shows the star cluster G286.21 + 0.17, caught in the act of formation. This is a multiple wavelength mosaic of over 750 ALMA radio images and 9 infrared images from Hubble. ALMA shows molecular clouds (purple) and Hubble shows stars and bright dust (yellow and red). ALMA (ESO / NAOJ / NRAO), Y. Cheng et al.; NRAO / AUI / NSF, S. Dagnello; NASA / ESA Hubble.
