Image of the star cluster G286.21 + 0.17, captured 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). Credit: ALMA (ESO / NAOJ / NRAO), Y. Cheng et al.; NRAO / AUI / NSF, S. Dagnello; NASA / ESA Hubble.
Astronomers created a surprising new image showing stellar fireworks in the star cluster G286.21 + 0.17.
Most of the stars in the universe, including our Sun, were born in large star clusters. These clusters are the building blocks of galaxies, but their formation from dense molecular clouds remains largely a mystery.
The image of the G286.21 + 0.17 group, caught in the act of formation, is a multi-wavelength mosaic made up of more than 750 individual radio observations with the Atacama Large Millimeter / submillimeter Array matrix (SOUL) and 9 infrared images of the POT/ THAT 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 animated gif shows the structure and movements (velocity toward the Sun) of the gas in the formation group, as seen with ALMA (purple) at the top of the Hubble infrared image. The scales from purple pink to purple blue represent gas moving at different speeds, from 15 km / s to 24 km / s. These movements are controlled by gravity, turbulence, and “feedback” from wind pressure and radiation from newborn stars. Credit: ALMA (ESO / NAOJ / NRAO), Y. Cheng et al.; NRAO / AUI / NSF, S. Dagnello; NASA / ESA Hubble.
“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.
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.”
References
“Stellar Variability in a Massive Star Cluster in Formation” by Yu Cheng, Morten Andersen, and Jonathan Tan, July 1, 2020, The Astrophysical Journal.
DOI: 10.3847 / 1538-4357 / ab93bc
“Gas kinematics of the massive G286.21 + 0.17 protocol revealed by ALMA” by Yu Cheng, Jonathan C. Tan, Mengyao Liu, Wanggi Lim, and Morten Andersen, May 8, 2020, The Astrophysical Journal.
DOI: 10.3847 / 1538-4357 / ab879f
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