Baby Supernova discovery hints at how star explosions are born

heavier than the sun and several hundred times wider than the sun, Yaron sai d.

The supernova detonated about 160 million light-years away in a spiral galaxy called NGC 7610. This galaxy is relatively close to the Milky Way, making it easier for scientists to aim more telescopes at it and detect signals from it that span almost the entire the spectrum of light, from radio waves to X-rays. Observations of the supernova were made with telescopes at the Keck Observatory in Hawaii and NASA's Swift satellite starting about 6 hours after the explosion, Yaron explained.

SN 2013fs was the most common variety of supernova: a Type II. This kind of supernova happens when the core of a massive star runs out of fuel, collapses to an extraordinarily dense nugget in a fraction of a second and then bounces and blasts its material outw ar d.

The astronomers captured pictures of the newborn supernova early enough to spot a disk of matter the star expelled just before its demise. Normally supernovas are seen after the shockwave from the explosions have swept away such material and any secrets that the disk might have contained.

The researchers found that a year or so before this star died, it rapidly spewed out vast amounts of material, equal to about onethousandth of the sun's mass, at speeds of nearly 224,000 mph (360,000 km/ h). Previous research had seen cases where such early eruptions occurred among unusual subgroups of Type II supernovas, but these new findings suggest that such outpourings also precede more common kinds of Type II supernovas.

"It's as if the star 'knows' its life is ending soon, and puffing material at an enhanced rate during its final breaths," Yaron told Space.com. "Think of a volcano or geyser bubbling before an eruption."

These findings suggest that a star may be unstable months before its turns into a Type II supernova. As such, "the structure of the star when it explodes may be different than that assumed so far," Yaron said. For instance, the core of a star may experience upheavals during its final days, causing strong winds to travel from the depths of the star all the way to its surface and beyond.