The death blast of a star

[ilan]

A massive star completely destroyed by a supernova is puzzling scientists
Korey Haynes | Published: Friday, August 16, 201

The death blast of a star some 200 times the mass of the Sun, challenges theories about how such massive stars die.

Supernova 2016iet is an example of one of the most extreme types of stellar explosions, though it has some odd features. Gemini Observatory/NSF/AURA/ illustration by Joy Pollard

In November of 2016, the sharp-eyed Gaia spacecraft spied a supernova that exploded some billion light-years from Earth. Astronomers followed up with more telescopes, and quickly realized that this supernova – dubbed SN2016iet – was an odd one in many ways.

For one, the star that caused the supernova seemed to orbit far in the hinterlands of its tiny, previously unknown dwarf galaxy, some 54,000 light-years from its center. Most massive stars are born in denser clusters of stars, and it’s a puzzle how this one came to form so far out.

And this star was extremely massive, starting life as some 200 times the mass of the Sun, near the upper limit of what scientists think is possible for a single star to weigh.

The supernova itself also left what appeared to be the signature of two explosions, separated by about 100 days. Astronomers think this isn’t actually due to multiple explosions, but from the explosion hitting different layers of material the star lost in the years leading up to its death and left scattered around it in a diffuse cloud.

The star meets many of the criteria for something called a pair-instability supernova, a kind of explosion that some extremely massive stars should theoretically undergo. Such an event leaves the star completely destroyed, leaving nothing behind. But finding examples of these rare stellar explosions has been difficult, and this is still one of the first scientists have discovered. And even in that rare company, SN2016iet remains an oddball find.

Researchers led by graduate student Sebastian Gomez from the Harvard Center for Astrophysics published their results August 15 in The Astrophysical Journal.

The same patch of sky is shown in 2014, before the supernova exploded, and in 2018, highlighting just how far outside the galaxy the explosion occurred.

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Imagine the amount of energy 2016iet emitted when it gave up the ghost! It's awesome to see an actual image of the supernova's remnants and the host galaxy in the second image. - ilan