Most of the stars in the universe – including our life-giving population 1, the main sequence Sun, one of more than 100 billion stars in the Milky Way galaxy that formed around 4.6 billion years ago – are massive star clusters that have arisen from violent gravity 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 edge of our Milky Way galaxy is encircled by approximately 150 globular clusters, which are among the oldest objects in the galaxy and were formed around 11.5 billion years ago, 2.3 billion years after the Big Bang and just before the speed of the cosmic star formation peaked Ten billion years ago – a time known as the “cosmic midday”. A globular cluster could be the first place to identify intelligent life in our galaxy, ”said Rosanne DiStefano of the Harvard-Smithsonian Center for Astrophysics (CfA).
Stars in these old clusters contain less of the heavy elements needed to build planets because these elements (such as iron and silicon) have to be created in younger generations of stars. Unlike DiStefano, some scientists have argued that this reduces the likelihood that 11-star planet populations will house planets. So far, only one planet has been found in a globular cluster.
The image of the cluster G286.21 + 0.17, which was taken when it was created, is a multi-wavelength mosaic consisting of more than 750 individual radio observations with the Atacama Large Millimeter / Submillimeter Array (ALMA) and 9 infrared images from NASA / ESA Hubble Space telescope. The cluster is located in the Carina region of our galaxy, about 8000 light years away.
Dense clouds of molecular gas (purple ‘firework streamer’) are discovered by ALMA. The telescope observed the movements of turbulent gas that fell into the cluster and formed dense nuclei that ultimately formed individual stars.
The stars in the image are visible through their infrared light seen by Hubble, including a large group of stars that pop out from one side of the cloud. The strong winds and radiation from the most massive of these stars blow up the molecular clouds and leave faint streaks of glowing, hot dust (shown in yellow and red).
“This image shows stars at various stages of education within this single cluster,” said Yu Cheng of the University of Virginia at Charlottesville, Virginia, and lead author of two articles published in the Astrophysical Journal.
“Oldest Objects in the Universe” – Hubble clues solve the puzzle of the globular galaxy clusters
Hubble revealed about a thousand newly formed stars with a wide range of masses. In addition, ALMA showed that there is much more mass in dense gas that still has to collapse. “Overall, the process can take at least a million years,” added Cheng.
“This shows 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, who is the project’s lead researcher. “We see competing forces in action: gravity and turbulence from the cloud on one side and star winds and radiation pressure from the young stars on the other. This process shapes the region. It’s amazing to think that our own sun and planets were once part of such a cosmic dance. “
“The phenomenal resolution and sensitivity of ALMA is reflected in this breathtaking picture of star formation,” said Joe Pesce, NSF program manager for NRAO / ALMA. “Combined with the Hubble Space Telescope data, we can clearly see the power of multi-wavelength observations to better understand these fundamental universal processes.”
Source: “Gas kinematics of the massive protocluster G286.21 + 0.17, 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 that is forming”, Yu Cheng et. al., The Astrophysical Journal. https://doi.org/10.3847/1538-4357/ab93bc
The Daily Galaxy, Max Goldberg, on the National Radio Astronomy Observatory
The image at the top of the page shows the star cluster G286.21 + 0.17, which was caught during the act of formation. This is a multi-wavelength mosaic of more than 750 ALMA radio images and 9 Hubble infrared images. ALMA shows molecular clouds (purple) and Hubble shows stars and glowing dust (yellow and red). ALMA (ESO / NAOJ / NRAO), Y. Cheng et al .; NRAO / AUI / NSF, S. Dagnello; NASA / ESA Hubble.