Blowing bubbles in the Carina Nebula

The Carina Nebula, by ESA’s Herschel space observatory. The image shows the effects of massive star formation – powerful stellar winds and radiation have carved pillars and bubbles in dense clouds of gas and dust.

The image covers approximately 2.3 x 2.3 degrees of the Carina Nebula complex and was mapped using Herschel instruments PACS and SPIRE at wavelengths of 70, 160, and 250 microns, corresponding to the blue, green, and red channels, respectively. North is to the upper left and east is to the lower left.

Credits: ESA/PACS/SPIRE/Thomas Preibisch, Universitäts-Sternwarte München, Ludwig-Maximilians-Universität München, Germany. HI-RES JPEG (Size: 1429 kb)

Giant bubbles, towering pillars and cascading clouds of dust and gas fill the star-forming nursery of the Carina Nebula seen here in a stunning new view from Herschel to launch ESA Space Science’s image of the week feature.

The Carina Nebula is some 7500 lightyears from Earth and hosts some of the most massive and luminous stars in our Galaxy, including double-star system eta Carinae, which boasts over 100 times the mass of our Sun.

The total amount of gas and dust traced by ESA’s Herschel space observatory in this image is equivalent to some 650 000 Suns. Including warmer gas not well traced by Herschel, the total mass may be as high as 900 000 Suns.

Surrounding pillars of gas and dust point towards the bright central region of nebulosity – home to eta Carinae and numerous other massive stars.

The pillars are carved by intense stellar winds and radiation blasted out by these stars, eating away at the surrounding material.

Above and to the left is a chaotic web of bubbles and broken bubble arcs molded by individual regions of star formation that have swept up shells of dense clouds around them.

At top right is the Gum 31 nebula, which has blown a giant bubble out of the surrounding dense clouds thanks to winds and radiation emitted by the young stellar cluster NGC 3324 that sits at its heart.

This latest Herschel image launches ESA Space Science’s new image of the week series, which will present a variety of images and animations capturing all aspects of space science from the Sun, planets, stars, and galaxies to the edge of the Universe, along with the spacecraft that provide us with these spectacular views.

Every week, look to the top right of the Space Science homepage and prepare to be amazed!

For further information, please contact:

Markus Bauer
ESA Science and Robotic Exploration Communication Officer
Tel: +31 71 565 6799
Mob: +31 61 594 3 954
Email: markus.bauer@esa.int

Göran Pilbratt
ESA Herschel Project Scientist
Research and Scientific Support Department
Science and Robotic Exploration Directorate
ESA, The Netherlands
Tel: +31 71 565 3621
Email: gpilbratt@rssd.esa.int

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Astronomers Watch Delayed Broadcast of a Powerful Stellar Eruption

Carina Nebula

Credit:NASA,NOAO, and A. Rest (Space Telescope Science Institute, Baltimore, Md.)
Acknowledgment: NOAO,AURA, NSF, and N. Smith (University of Arizona)

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Astronomers are watching a delayed broadcast of a spectacular outburst from the unstable, behemoth double-star system Eta Carinae, an event initially seen on Earth nearly 170 years ago.

Dubbed the "Great Eruption," the outburst first caught the attention of sky watchers in 1837 and was observed through 1858. But astronomers didn't have sophisticated science instruments to accurately record the star system's petulant activity.

Luckily for today's astronomers, some of the light from the eruption took an indirect path to Earth and is just arriving now, providing an opportunity to analyze the outburst in detail. The wayward light was heading in a different direction, away from our planet, when it bounced off dust clouds lingering far from the turbulent stars and was rerouted to Earth, an effect called a "light echo." Because of its longer path, the light reached Earth 170 years later than the light that arrived directly.

The observations of Eta Carinae's light echo are providing new insight into the behavior of powerful massive stars on the brink of detonation. The views of the nearby erupting star reveal some unexpected results, which will force astronomers to modify physical models of the outburst.

"When the eruption was seen on Earth 170 years ago, there were no cameras capable of recording the event," explained the study's leader, Armin Rest of the Space Telescope Science Institute in Baltimore, Md. "Everything astronomers have known to date about Eta Carinae's outburst is from eyewitness accounts. Modern observations with science instruments were made years after the eruption actually happened. It's as if nature has left behind a surveillance tape of the event, which we are now just beginning to watch. We can trace it year by year to see how the outburst changed."

The team's paper will appear Feb. 16 in a letter to the journal Nature.

Located 7,500 light-years from Earth, Eta Carinae is one of the largest and brightest star systems in our Milky Way galaxy. Although the chaotic duo is known for its petulant outbursts, the Great Eruption was the biggest ever observed. During the 20-year episode, Eta Carinae shed some 20 solar masses and became the second brightest star in the sky. Some of the outflow formed the system's twin giant lobes. Before the epic event, the stellar pair was 140 times heftier than our Sun.

Because Eta Carinae is relatively nearby, astronomers have used a variety of telescopes, including the Hubble Space Telescope, to document its escapades. The team's study involved a mix of visible-light and spectroscopic observations from ground-based telescopes.

The observations mark the first time astronomers have used spectroscopy to analyze a light echo from a star undergoing powerful recurring eruptions, though they have measured this unique phenomenon around exploding stars called supernovae. Spectroscopy captures a star's "fingerprints," providing details about its behavior, including the temperature and speed of the ejected material.

The delayed broadcast is giving astronomers a unique look at the outburst and turning up some surprises. The turbulent star system does not behave like other stars of its class. Eta Carinae is a member of a stellar class called Luminous Blue Variables, large, extremely bright stars that are prone to periodic outbursts. The temperature of the outflow from Eta Carinae's central region, for example, is about 8,500 degrees Fahrenheit (5,000 Kelvin), which is much cooler than that of other erupting stars. "This star really seems to be an oddball," Rest said. "Now we have to go back to the models and see what has to change to actually produce what we are measuring."

Rest's team first spotted the light echo while comparing visible-light observations he took of the stellar duo in 2010 and 2011 with the U.S. National Optical Astronomy Observatory's Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile. He obtained another set of CTIO observations taken in 2003 by astronomer Nathan Smith of the University of Arizona in Tucson, which helped him piece together the whole 20-year outburst.

The images revealed light that seemed to dart through and illuminate a canyon of dust surrounding the doomed star system. "I was jumping up and down when I saw the light echo," said Rest, who has studied light echoes from powerful supernova blasts. "I didn't expect to see Eta Carinae's light echo because the eruption was so much fainter than a supernova explosion. We knew it probably wasn't material moving through space. To see something this close move across space would take decades of observations. We, however, saw the movement over a year's time. That's why we thought it was probably a light echo."

Although the light in the images appears to move over time, it's really an optical illusion. Each flash of light is reaching Earth at a different time, like a person's voice echoing off the walls of a canyon.

The team followed up its study with spectroscopic observations, using the Carnegie Institution of Washington's Magellan and du Pont telescopes at Las Campanas Observatory in Chile. That study helped the astronomers decode the light, revealing the outflow's speed and temperature. The observations showed that ejected material was moving at roughly 445,000 miles an hour (more than 700,000 kilometers an hour), which matches predictions.

Rest's group monitored changes in the intensity of the light echo using the Las Cumbres Observatory Global Telescope Network's Faulkes Telescope South in Siding Spring, Australia. The team then compared those measurements with a plot astronomers in the 1800s made of the light brightening and dimming over the course of the 20-year eruption. The new measurements matched the signature of the 1843 peak in brightness.

The team will continue to follow Eta Carinae because light from the outburst is still streaming to Earth. "We should see brightening again in six months from another increase in light that was seen in 1844," Rest said. "We hope to capture light from the outburst coming from different directions so that we can get a complete picture of the eruption."

Rest's team consists of J.L. Prieto, Carnegie Observatories, Pasadena, Calif.; N.R. Walborn and H.E. Bond, Space Telescope Science Institute, Baltimore, Md.; N. Smith, Steward Observatory, University of Arizona, Tucson; F.B. Bianco and D.A. Howell, Las Cumbres Observatory Global Telescope Network, Goleta, Calif., and University of California, Santa Barbara; R. Chornock, R.J. Foley, and W. Fong, Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.; D.L. Welch and B. Sinnott, McMaster University, Hamilton, Ontario; M.E. Huber, Johns Hopkins University, Baltimore, Md.; R.C. Smith, Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, La Serena, Chile; I. Toledo, Atacama Large Millimeter Array (ALMA), Chile; D. Minniti, Pontifica Universidad Catolica, Santiago, Chile; and K. Mandel, Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass., and Imperial College London, U.K.

CONTACT

Donna Weaver
Space Telescope Science Institute, Baltimore, Md.
410-338-4514
dweaver@stsci.edu

Armin Rest
Space Telescope Science Institute, Baltimore, Md.
410-338-4358
arest@stsci.edu

More about → Astronomers Watch Delayed Broadcast of a Powerful Stellar Eruption

Return to the Carina Nebula

Carina Nebula
Credit: ESA/Hubble & NASA

Looking like an elegant abstract art piece painted by talented hands, this picture is actually a NASA/ESA Hubble Space Telescope image of a small section of the Carina Nebula. Part of this huge nebula was documented in the well-known Mystic Mountain picture (heic1007a) and this picture takes an even closer look at another piece of this bizarre astronomical landscape (heic0707a).

The Carina Nebula itself is a star-forming region about 7500 light-years from Earth in the southern constellation of Carina (The Keel: part of Jason’s ship the Argo). Infant stars blaze with a ferocity so severe that the radiation emitted carves away at the surrounding gas, sculpting it into strange structures. The dust clumps towards the upper right of the image, looking like ink dropped into milk, were formed in this way. It has been suggested that they are cocoons for newly forming stars.

The Carina Nebula is mostly made from hydrogen, but there are other elements present, such as oxygen and sulphur. This provides evidence that the nebula is at least partly formed from the remnants of earlier generations of stars where most elements heavier than helium were synthesised.

The brightest stars in the image are not actually part of the Carina Nebula. They are much closer to us, essentially being the foreground to the Carina Nebula’s background.

This picture was created from images taken with Hubble’s Wide Field Planetary Camera 2. Images through a blue filter (F450W) were coloured blue and images through a yellow/orange filter (F606W) were coloured red. The field of view is 2.4 by 1.3 arcminutes.

More about → Return to the Carina Nebula