Eta Carinae is a binary system containing the most luminous and massive star within 10,000 light-years. A long-term study led by astronomers at NASA's Goddard Space Flight Center in Greenbelt, Maryland, combined data from NASA satellites, ground-based observing campaigns and theoretical modeling to produce the most comprehensive picture of Eta Carinae to date. New findings include Hubble Space Telescope images that show decade-old shells of ionized gas racing away from the largest star at a million miles an hour, and new 3-D models that reveal never-before-seen features of the stars' interactions.

Located about 7,500 light-years away in the southern constellation of Carina, Eta Carinae comprises two massive stars whose eccentric orbits bring them unusually close every 5.5 years. Both produce powerful gaseous outflows called stellar winds, which enshroud the stars and stymy efforts to directly measure their properties. Astronomers have established that the brighter, cooler primary star has about 90 times the mass of the sun and outshines it by 5 million times. While the properties of its smaller, hotter companion are more contested, Goddard's Ted Gull and his colleagues think the star has about 30 solar masses and emits a million times the sun's light.

At closest approach, or periastron, the stars are 140 million miles (225 million kilometers) apart, or about the average distance between Mars and the sun. Astronomers observe dramatic changes in the system during the months before and after periastron. These include X-ray flares, followed by a sudden decline and eventual recovery of X-ray emission; the disappearance and re-emergence of structures near the stars detected at specific wavelengths of visible light; and even a play of light and shadow as the smaller star swings around the primary. 

During the past 11 years, spanning three periastron passages, the Goddard group has developed a model based on routine observations of the stars using ground-based telescopes and multiple NASA satellites. According to this model, the interaction of the two stellar winds accounts for many of the periodic changes observed in the system. The winds from each star have markedly different properties: thick and slow for the primary, lean and fast for the hotter companion. The primary's wind blows at nearly 1 million mph and is especially dense, carrying away the equivalent mass of our sun every thousand years. By contrast, the companion's wind carries off about 100 times less material than the primary's, but it races outward as much as six times faster. 

The images and video on this page include periastron observations from NASA's Rossi X-ray Timing Explorer, the X-Ray Telescope aboard NASA's Swift, the Hubble Space Telescope's STIS instrument, and computer simulations. See the captions for details.

This video is public domain and can be downloaded at: http://svs.gsfc.nasa.gov/goto?11725 

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NASA | Missions Take an Unparalleled Look into Superstar Eta Carinae

Video summary of the Goddard research. Credit: [​NASA Goddard/YouTube](https://www.youtube.com/watch?v=0rJQi6oaZf0).

The star system Eta Carinae is, to date, basically a giant cosmic volcano. Located 7,500 light-years away in the constellation Carina, the system is comprised of two mind-bogglingly massive stars&#x2014;each millions of times brighter than the Sun&#x2014;that explosively interact. As a result, the Eta Carinae system is by far the largest and brightest object within 10,000 light years of Earth.

Scientists have long been fascinated by the system's volatile and ultra-luminous nature, which is why astronomers based out of NASA's Goddard Space Flight Center pulled out all the stops with their latest investigation into Eta Carinae. For over a decade, Goddard researchers have been monitoring the monster stars with both space and ground-based telescopes, and using the NASA's Pleiades supercomputer to model the data.

The result are the most accurate and comprehensive images and video simulations of this epic stellar light show ever created, which the team [​released](http://www.nasa.gov/content/goddard/nasa-observatories-take-an-unprecedented-look-into-superstar-eta-carinae/#.VK6qTmTF_fe) Wednesday evening at the 225th American Astronomical Association meeting.

"We are coming to understand the present state and complex environment of this remarkable object," said astrophysicist Ted Gull, who coordinated the effort, in a [​NASA statement](http://www.nasa.gov/content/goddard/nasa-observatories-take-an-unprecedented-look-into-superstar-eta-carinae/#.VK6qtWTF_fd). "But we have a long way to go to explain Eta Carinae's past eruptions or to predict its future behavior."

As the video above explains, the blazing luminosity at the heart of Eta Carinae is the result of the two stars [​barreling toward their periastron](http://astronomy.swin.edu.au/cosmos/P/Periastron)&#x2014;the point of closest orbit&#x2014;every five and a half years. Considering that the stars weigh 30 and 90 solar masses respectively, and that they end up about as far from each other as Mars is from the Sun, it's easy to understand why the system is such a luminous juggernaut. You can't just chuck giant stars at each other and not expect some fireworks.

Still, the video and the accompanying explanation are worth watching and reading in full, because there are a lot of weird, finer details revealed by the Goddard researchers. From the Fibonacci-like spiral the close encounter creates to [​the system's emission of lasers](http://apod.nasa.gov/apod/ap971129.html), Eta Carinae continues to be full of surprises.

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Watch the Brightest Star System Near Earth Explode

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Watch the Brightest Star System Near Earth Explode

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