Astronomers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with the help of NASA satellites and ground-based telescopes gathered enough data to create an accurate 3-D model of the “stellar monster” Eta Carinae.
Eta Carinae is actually two stars locked in orbit, located 7,500 light years away, in the southern constellation of Carina. The two stars come close once every 5.5 years. Both of them generate large quantities of gas that form stellar winds. The primary star is brighter but cooler, with a mass 90 times bigger than that of the Sun’s. Its brightness is 5 million times stronger than that of our Sun. The second star is smaller, hotter and one million times brighter than the Sun.
During the periastron, which is when the two stars come close, the distance between them is about 140 million miles (225 million kilometers).Scientists noticed important changes during the months before and after periastron. This includes a powerful outburst of X-Rays, followed by a decrease and a final state of balance. At specific light wavelengths, astronomers detected the disappearance and reappearance of certain structures.
Using the data gathered throughout 3 periastrons (11 years), a member of the Goddard team, Tom Madura, set up a computer simulation that will help the team understand how the next cycle will look like. At the end of the next cycle, the newly acquired data will be introduced in the computer model, thus improving the next simulation.
According to the model, the changes observed are mainly due to the interactions between the stars’ stellar winds which have different proprieties. The wind produced by the primary star is described as “thick and slow”, blowing with a speed of 1 million miles/hour. It is also very dense. By comparison, the second star generates a leaner, faster wind.
The simulations were performed on the Pleiades supercomputer at NASA’s Ames Research Center in Moffett Field, California, revealing the complex interactions between the two winds. When the companion turns around the primary star, its fast wind sculpts a spiral-shaped cavity in the dense airflow that surrounds the main star.
In order to have a better view of the process, Madura transformed the simulation into 3-d digital models that later became solid versions. The 3-D parts can be freely downloaded and constructed everyone who wishes to do so.
Like any other star, the Eta Carinae might one day end its life in a supernova explosion. Researchers do not have data that suggest the event will happen soon, but in it’s final moments, “it’s going to be a source of daylight comparable to the moon – but a point source” said Goddard astrophysicist Ted Gull.
Image Source: Wikipedia
