— NASA's Hubble confirms that galaxies are the ultimate recyclers — New observations by NASA's Hubble Space Telescope are expanding astronomers' understanding of the ways in which galaxies continuously recycle immense volumes of hydrogen gas and heavy…
— Frozen comet had a watery past, University of Arizona scientists find — For the first time, scientists have found convincing evidence for the presence of liquid water in a comet, shattering the current paradigm that comets never get warm enough to melt…
— Sugar-grain sized meteorites rocked the climates of early Earth and Mars — Bombardments of 'micro-meteorites' on Earth and Mars four billion years ago may have caused the planets' climates to cool dramatically, hampering their ability to support life, according…
— Astrophysicist: White dwarfs could be fertile ground for other Earths — Planet hunters have found hundreds of planets outside the solar system in the last decade, though it is unclear whether even one might be habitable. But it could be that the best place…
— Integral spots matter a millisecond from doom — ESA's Integral gamma-ray observatory has spotted extremely hot matter just a millisecond before it plunges into the oblivion of a black hole. But is it really doomed? These unique observations…
— MESSENGER spacecraft to swing into orbit around Mercury — At 8:45 p.m. EDT on March 17, the MESSENGER spacecraft will execute a 15-minute manoeuvre that will place it into orbit around Mercury, making it the first craft ever to do so, and…
— Baby stars born to 'napping' parents — Cardiff University astronomers believe that a young star's long 'napping' could trigger the formation of a second generation of smaller stars and planets orbiting around it…
— Oldest objects in solar system indicate a turbulent beginning — Scientists have found that calcium, aluminium-rich inclusions (CAIs), some of the oldest objects in the solar system, formed far away from our sun and then later fell back into the…
— Oxygen isotope analysis tells of the wandering life of a dust grain 4.5 billion years ago — Scientists have performed a micro-probe analysis of the core and outer layers of a pea-sized piece of a meteorite some 4.57 billion years old to reconstruct the history of its formation,…
Splashy portrait helps explain how stars form
Different wavelengths of light swirl together like watercolors in a new, ethereal portrait of a bright, star-forming region. The multi-wavelength picture combines infrared, visible and X-ray light from NASA's Spitzer Space Telescope, the European Southern Observatory's New Technology Telescope, and the European Space Agency's XMM-Newton orbiting X-Ray telescope, respectively.
The colourful image offers a fresh look at the history of the star-studded region, called NGC 346, revealing new information about how stars form in the universe. NGC 346 is the brightest star-forming region in the Small Magellanic Cloud, a so-called irregular dwarf galaxy that orbits our Milky Way galaxy, 210,000 light-years away.
'NGC 346 is an astronomical zoo,' said Dimitrios Gouliermis of the Max Planck Institute for Astronomy in Germany, lead author of a new paper describing the observations in an upcoming issue of the Astrophysical Journal. 'When we combined data at various wavelengths, we were able to tease apart what's going on in different parts of the cloud.'
Small stars are scattered throughout the NGC 346 region, while massive stars populate its centre. The massive stars and most of the small stars formed at the same time out of one dense cloud, while other small stars were created later through a process called triggered star formation. Intense radiation from 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 a set of even younger small stars in the region, seen as a pinkish blob at the top of the image, couldn't be explained by this mechanism. Scientists were scratching their heads over what caused this seemingly isolated group of stars to form.
By combining multi-wavelength data of NGC 346, Gouliermis says he 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. According to the astronomers, this very massive star spurred the isolated young stars into existence before it died, but through a different type of triggered star formation than that which occurred near the centre of the region. Fierce winds from the massive star, and not radiation, pushed dust and gas together, compressing it into new 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 believe, comprising different competitive or collaborative mechanisms.'
The new image also reveals a bubble, seen as a blue halo to the left, caused by the supernova explosion that happened 50,000 years ago. Further analysis shows that this bubble is located within a large expanding gaseous shell, possibly powered by the explosion and the winds of other bright stars in its vicinity.
Infrared light (red) shows cold dust; visible light (green) denotes glowing gas; and X-rays (blue) represent very warm gas. Ordinary stars appear as blue spots with white centres, while young stars enshrouded in dust appear as red spots with white centres.
Other authors of this paper include Thomas Henning and Wolfgang Brandner of the Max Planck Institute for Astronomy, and You-Hua Chu and Robert Gruendl of the University of Illinois at Urbana-Champaign.
Or subscribe for our Newsletter, a free e-mail publication. It is published practically every day.
Jupiter scar likely from rocky body
Runaway star plows through space
The Orion nebula: Still full of surprises
Cassini rocks Rhea rendezvous