Stars form in huge clouds of gas and dust, and the moment they start shining, they can destroy the excess gas and carve spectacular structures inside these nebulae. The Carina Nebula, located 7,500 light-years from Earth in the Milky Way, is one of these large clouds and, thanks to new observations, astronomers have gotten a better understanding of how the gas is eroded away.
An international team of researchers used the Multi Unit Spectroscopic Explorer (MUSE) instrument on the Very Large Telescope (VLT) in Chile to study how the ionizing radiation from newborn stars first formed and is now destroying the pillars of the Carina Nebula.
These pillars have been dubbed the "Pillars of Destruction", a play on the well-known similar feature of the Eagle Nebula known as the Pillars of Creation. In a paper published in the Monthly Notices of the Royal Astronomical Society, the researchers combined the data from the Carina Nebula with the Pillars of Creation and another similar region called NGC 3603, and they discovered a clear link between the amount of powerful light emitted by the nearby stars and the features in the pillars.
The astronomers discovered six pillars within the Carina Nebula, each several light-years in length. They are being destroyed by a process called photoevaporation, where the gas of the nebula is heated and pushed away. Using the newly installed MUSE, the team was able to measure the mass loss of these structures and even work out the intensity of the stellar culprits.
"By combining observations from different regions instead of analyzing only a single one, we were able to determine the quantitative connection between the ionizing massive stars and their effect on the surrounding clouds," lead author Dr Anna Faye McLeod from the European Southern Observatory (ESO) told IFLScience.
"This is very important, as we know that the effect of the massive stars is that they photoevaporate the clouds and shape them into pillar-like structures, but now we also know (from an observational point of view) what exactly this photoevaporating effect is in terms of numbers, depending on the amount of massive stars that are acting on the regions."
Different pillars from the Carina Nebula as seen by MUSE. ESO/A. McLeod
This study provides some new information on the feedback mechanism between star-formation and birth clouds. While we have been aware of the role new stars play in dissipating gas, the exact details of these processes have been vague. This research is a first but big step in better understanding the infancy of stars, which will help us to create better models for galaxy evolution. The researchers are planning to investigate more regions like this, even beyond the Milky Way.
"This study is an important step towards [understanding massive star formation feedback], as we were able to confirm the predictions of photoevaporation coming from the models, and we can now implement this quantification in the more feedback recipes of galaxy evolution models," said McLeod. "What is still needed is to observationally quantify the effect of the other mechanisms as well. We are working on it!"
The nebulae and pillars look like colorful clouds in space, but in reality they are significantly less dense than even fog or smoke on Earth. Nebulae have an average density of 100 to 1,000 particles per cubic centimeter, but they appear thick due to their impressive size.