The Carina Nebula is one of the largest and brightest nebulae in the night sky and has now been beautifully imaged by ESO’s (European Southern Observatory) VISTA telescope at the Paranal Observatory in Chile. By observing in infrared light, VISTA has peered through the hot gas and dark dust enshrouding the nebula to show us myriad stars, both newborn and in their death throes.
The constellation of Carina is about 7,500 light-years away and the home of a nebula within which stars form and perish side-by-side. The massive stars in the interior of this cosmic bubble emit intense radiation that causes the surrounding gas to glow. By contrast, other regions of the nebula contain dark pillars of dust cloaking newborn stars. There’s a battle raging between stars and dust in the Carina Nebula, and the newly formed stars are winning by producing high-energy radiation and stellar winds which evaporate and disperse the dusty stellar nurseries in which they formed.
Despite the big distance between Earth and the Carina Nebula, the findings in those photos are of invaluable significance for astronomers. “We want to better understand how stars and planets form, and the environment they form in which is why studying a relatively nearby region of active star formation is so useful,“ Jim Emerson at School of Physics & Astronomy, Queen Mary University of London, explains. “Apart from the overview from the image the science is mostly done using catalogs of all the objects which we extract from the image in each of the individual colors (filters) used in the observations.“
Emerson first observed the Carina Nebula in 1973 but “with a single detector (no image) from a ballon borne telescope at wavelengths about 100 times longer than the Infrared of the current image,“ he says. “The current photo was made from images acquired every night over a period of a week in 2010. VISTA has observed it again several times since then in the course of its sky survey work.“
He admits that he was surprised by the beauty seen in the latest pictures. They were “stunning“, however he was not surprised by the clarity. “This image was taken using VISTA, the Visible and Infrared Survey Telescope for Astronomy, which works at near-infrared wavelengths and is currently the world’s largest dedicated survey telescope“Calum Turner, public information officer at ESO says. “ VISTA’s sensitive detectors and the amazing observing conditions at ESO’s Paranal Observatory have produced many beautiful images such as this one in the past, so I was not surprised by the clarity of the image — though it certainly is eye-catching!“
No direct indication about the history of Earth
The new pictures don’t give any indication about the history of our planet or its future, Emerson emphasizes. „Not directly. We can’t see any planets in these images because they are all too close to their much brighter host stars.“ However, other techniques could find them. “Astrophysicists compare what they find to theoretical models of how and where stars form and this interplay step by step improves the accuracy of the models. The models are then applied to a star of the mass of our Sun to give insights about its future.“ In the “very, very, very distant future” sun would also begin to run out of hydrogen to burn and at that stage it’s appearance would begin to change, he admits, but readers should not worry about that, because it is so far off in time. “Earth has other issues that need solving much sooner.“
And what are the chances that there are habitable planets in that nebula? “Well, nebulae like Carina are the birthplaces of stars, some of which can be seen in this image“, so Turner. „In the last 25 years, we’ve discovered that many stars have planets, which form in a disc around the star when it’s still very young. There’s no reason that the stars forming in Carina won’t host planets also in the process of forming. However, these planets would still be very young, continuously bombarded by asteroids, very unstable, and unlikely to be habitable. I certainly wouldn’t want to live there!”
The pictures we see now, show the nebula in its state as is was 7,500 years ago, but Turner does not assume that is has changed much since then. “7,500 years may sound like a lot of time — it’s roughly the length of time that human civilization has existed, but it’s a blink of an eye in astronomical terms. I wouldn’t expect any huge changes, but then again I’m not an expert.”
Spanning over 300 light-years, the Carina Nebula is one of the Milky Way’s largest star-forming regions and is easily visible to the unaided eye under dark skies; unfortunately only from the Southern Hemisphere, since it lies 60 degrees below the celestial equator.
Within this intriguing nebula, Eta Carinae takes pride of place as the most peculiar star system. This stellar behemoth is the most energetic star system in this region and was one of the brightest objects in the sky in the 1830s. It has since faded dramatically and is reaching the end of its life, but remains one of the most massive and luminous star systems in the Milky Way.
Eta Carinae can be seen in the cover picture of this article as part of the bright patch of light just above the point of the “V” shape made by the dust clouds. Directly to the right of Eta Carinae is the relatively small Keyhole Nebula – a small, dense cloud of cold molecules and gas within the Carina Nebula – which hosts several massive stars, and whose appearance has also changed drastically over recent centuries.
The Carina Nebula was discovered from the Cape of Good Hope by Nicolas Louis de Lacaille in the 1750s and a huge number of images have been taken of it since then. But thanks to its infrared vision, VISTA – the Visible and Infrared Survey Telescope for Astronomy – adds an unprecedentedly detailed view over a large area.
Copyright cover picture : ESO/J. Emerson/M. Irwin/J. Lewis
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