Image Credit: ESO/ESA/JPL-Caltech/NASA/D. Gouliermis (MPIA) et al
The
Small Magellanic Cloud (SMC) might be small by name, but that doesn't mean it's actually small. In fact, by human standards, it's quite large, spanning around 7,000 light-years across (Okay. So it's nothing in the grand scheme of things; It is a dwarf galaxy, after all).
The image above features one of the most beautiful star forming regions the Small Magellanic Cloud has to offer—called
NGC 346, it can be found approximately 210,000 light-years from Earth in the constellation of Tucana.
The many colorful facets of NGC 346 can be attributed to a young cluster of stars that are currently in the process of biting the hand that feeds them (i.e. the gaseous envelope from which they came). Thankfully (for us), the resulting nebula is super nice to look at.
Another view of NGC 94 (Credit: Image: X-ray: NASA/CXC/CfA/R. Tuellmann et al.; Optical: NASA/AURA/STScI)
As they continued to eat their way out of their stellar cocoon, we will see more and more of the cloud's inwards, until there's nothing left. The European Southern Observatory(ESO) divulges further:
[box style="0"] "NGC 346 is a real astronomical zoo," says Dimitrios Gouliermis of the Max Planck Institute for Astronomy in Heidelberg, Germany, and lead author of the paper describing the observations. "When we combined data at various wavelengths, we were able to tease apart what's going on in different parts of this intriguing region."
Small stars are scattered throughout the NGC 346 region, while massive stars populate its centre. These massive stars and most of the small ones formed at the same time out of one dense cloud, while other less massive stars were created later through a process called "triggered star formation". Intense radiation from the massive stars ate away at the surrounding dusty cloud, triggering gas to expand and create shock waves that compressed nearby cold dust and gas into new stars. The red-orange filaments surrounding the centre of the image show where this process has occurred.
But another set of younger low-mass stars in the region, seen as a pinkish blob at the top of the image, couldn't be explained by this mechanism. "We were particularly interested to know what caused this seemingly isolated group of stars to form," says Gouliermis.
By combining multi-wavelength data of NGC 346, Gouliermis and his team were able to pinpoint the trigger as a very massive star that blasted apart in a supernova explosion about 50 000 years ago. Fierce winds from the massive dying star, and not radiation, pushed gas and dust together, compressing it into new stars, bringing the isolated young stars into existence. While the remains of this massive star cannot be seen in the image, a bubble created when it exploded can be seen near the large, white spot with a blue halo at the upper left (this white spot is actually a collection of three stars).
The finding demonstrates that both wind- and radiation-induced triggered star formation are at play in the same cloud. According to Gouliermis, "the result shows us that star formation is a far more complicated process than we used to think, comprising different competitive or collaborative mechanisms."
The analysis was only possible thanks to the combination of information obtained through very different techniques and equipments. It reveals the power of such collaborations and the synergy between ground- and space-based observatories.
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