Surprising new observations of the system, known as Eta Carinae, described Wednesday at the American Astronomical Society‘s annual winter meeting, include a set of oddly bright flares that might signal a change in the two stars’ billowing stellar winds. What’s more, 3-D printed simulations show unexpected anatomy within the star system’s churning, tempestuous center.
Scientists have kept a close eye on Eta Carinae since the 1840s, when a series of unexpected eruptions briefly transformed it into the brightest star in the southern sky. At any time, the unstable system could explode in a spectacular supernova. (Don’t worry—Earth will be fine. But the light show will be unforgettable.)
The new observations don’t pin down when Eta Carinae might explode, but they are helping astronomers better understand the turbulent pair.
“It’s not only the most massive and luminous object that’s close to us, but it’s also extremely erratic,” says astronomer Michael Corcoran of NASA’s Goddard Space Flight Center, in Greenbelt, Maryland.
It looks like a single point of light in the constellation Carina, but Eta Carinae (7,500 light-years away) is actually the violent, unstable product of two giant stars, one big and one smaller, whirling around each other. The smaller star, a relatively puny 30 solar masses, escaped notice until 1996. The primary star is at least 90 times more massive than the sun, and five million times brighter.
“As a result of this extreme luminosity, the stars are basically blowing themselves apart,” Corcoran says.
Every 5.5 years, the smaller star completes a slingshot-like orbit around the bigger star, and at their closest the two snuggle in as near as Mars is to the sun.