Astronomers using ESO’s Very Large Telescope (VLT) have observed giant pillar-like structures within the Carina Nebula, a huge star-formation region in the constellation of Carina.
This image, taken by ESO’s Very Large Telescope, shows the region R18 within the Carina Nebula. The massive stars within the star formation region slowly destroy the pillars of dust and gas from which they are born. Image credit: A. McLeod / ESO.
The Carina Nebula is some 7,500 light-years distant. It was discovered in the 1750s by French astronomer Nicolas Louis de Lacaille.
Also known as NGC 3372 and Caldwell 92, the nebula is about 150 light-years across.
It is among the brightest nebulae in the sky and is one of the closest incubators of very massive stars to our Solar System.
The spires and pillars in the new images of the nebula are vast clouds of dust and gas.
They were observed by a research team, led by ESO astronomer Anna McLeod, using VLT’s MUSE (Multi-Unit Spectroscopic Explorer) instrument.
In total 10 pillars have been observed, and in so doing a clear link was observed between the radiation emitted by nearby massive stars and the features of the pillars themselves.
These images show pillars within the Carina Nebula which were observed and studied with ESO’s Very Large Telescope. Image credit: A. McLeod / ESO.
In an ironic twist, one of the first consequences of the formation of a massive star is that it starts to destroy the cloud from which it was born.
The idea that massive stars will have a considerable effect on their surroundings is not new: such stars are known to blast out vast quantities of powerful, ionizing radiation — emission with enough energy to strip atoms of their orbiting electrons.
However, it is very difficult to obtain observational evidence of the interplay between such stars and their surroundings.
McLeod and co-authors analyzed the effect of this energetic radiation on the pillars: a process known as photoevaporation.
By observing the results of photoevaporation — which included the loss of mass from the pillars — they were able to deduce the culprits.
There was a clear correlation between the amount of ionizing radiation being emitted by nearby stars, and the dissipation of the pillars.
This might seem like a cosmic calamity, with massive stars turning on their own creators.
However the complexities of the feedback mechanisms between the stars and the pillars are poorly understood.
These pillars might look dense, but the clouds of dust and gas which make up nebulae are actually very diffuse.
It is possible that the radiation and stellar winds from massive stars actually help create denser spots within the pillars, which can then form stars.
The team’s findings have been accepted for publication in the Monthly Notices of the Royal Astronomical Society (arXiv.org preprint).
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A.F. McLeod et al. 2016. Connecting the dots: a correlation between ionising radiation and cloud mass-loss rate traced by optical integral field spectroscopy. MNRAS, accepted for publication; arXiv:1608.00005
