This Galaxy Hosted One of the Most Powerful Supernovae Ever Seen

In 2010, an exceptionally luminous supernova exploded in a small galaxy about 150 million light-years away called UGC 5189A. The Hubble Space Telescope has kept its eye on this galaxy because of the extraordinary supernova, which for three years released more than 2.5 billion times the energy of our Sun in visible light alone.

Though the supernova, named SN 2010jl, died down years ago, astronomers are still watching its aftermath.

While a supernova explosion is a cataclysmic event that’s more luminous than the galaxy that hosts it, what happens after it explodes is just as compelling. An explosion that powerful changes its surroundings, and astronomers examine the aftermath to understand more about how it happened.

“The bright Type IIn SN 2010jl is an interesting laboratory for the study of dust formation, evolution, and destruction.”

– “Disentangling Dust Components in SN 2010jl: The First 1400 Days” – APJ

When a supernova explodes, it leaves behind a remnant, either a neutron star or a stellar-mass black hole. Both of those objects rank high on the fascination scale. A black hole is a mind-bending singularity from which not even light can escape. A neutron star is a weird sphere made almost entirely of neutrons. Scientists aren’t exactly certain, but the extreme gravitational pressure in a neutron star might squeeze the protons and electrons so much that they turn into neutrons.

But aside from the stellar object they leave behind, supernovae have other effects on their surroundings. They create dust and gas, disperse heavy elements into their surroundings, and their shockwaves can even trigger the birth of more stars.

Supernovae are known to create dust in their surroundings, as this artist’s illustration shows. Image Credit: ESO / M. Kornmesser

SN 2010jl was a type IIn supernova. But since its discovery, astronomers have been studying it closely, and they observed a mid-infrared brightening that lasted longer than 1,000 days. This puts SN 2010jl in a class of its own, and now it’s the namesake for a new sub-type of type IIn supernovae.

This 2012 composite image shows the galaxy UGC 5189A in X-ray data from Chandra (purple) and optical data from Hubble (red, green and blue.) The very bright source near the top of the galaxy is SN 2010jl. Image Credit: X-ray: NASA/CXC/Royal Military College of Canada/P.Chandra et al.); Optical: NASA/STScI

SN 2010jl interacts strongly with its dense circumstellar medium. A 2020 paper said that as shocks travel outward from the supernova, they hit the dense medium and bounce back into the SN’s ejecta. The region between the two shocks cools rapidly, forming dust. But most of the dust is then destroyed, and only about 20% of it survives. This is a complicated set of interactions that astronomers want to know more about. “The bright Type IIn SN 2010jl is an interesting laboratory for the study of dust formation, evolution, and destruction,” the authors of the 2020 paper said.

This diagram shows a clumpy circumstellar medium surrounding SN 2010jl. As the expanding ejecta strikes dense clumps in the CSM, some of the shock waves bounce back toward the SN. Dust forms in the cooling region between the two shock waves. The outer torus is what caused the supernova’s infrared luminosity. Image Credit: Bevan et al. 2020.

The destruction of the dust is related to SN 2010jl’s unusual near-infrared brightening. Astronomers think that the IR brightness came from the portion of the dust that was destroyed. As shock waves from the supernova burst through the stellar surface, it generated an intense burst of energy. That energy evaporated the dust, generating the IR brightness, according to a 2021 paper.

Supernovae are more than just exploding stars. They’re part of Nature’s great recycling. How they explode, how they create metals and spread them out into space, and how they shape their surroundings are all active areas of study.

There’s a lot going on in the region around a supernova after it explodes. Shock waves bounce off one another, dust is created and then destroyed, and different parts of the remnant’s anatomy light up with different energies at different times.

As SN 2010jl shows us, supernovae are dynamic objects that shape their environments long after they explode. By observing their remnants for many years, astronomers are answering key questions about the progenitor stars that exploded and the ongoing aftermath.

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