Rare first moment of stellar explosion captured by amateur astronomer

February 22, 2018

The moment a supernova becomes visible in the sky has been captured by an amateur astronomer, and has helped an international team of researchers validate theoretical predictions about the initial evolution of such stellar explosions.

How the structure of the exploding star affects the supernova properties. has remained an open question, but understanding it would be a significant step forward in astrophysics research. Current theory suggests an explosive shockwave travels through the star's interior before reaching the surface and producing a sharp peak of electromagnetic emission. The strength and duration of this signal, known as shock breakout is believed to largely depend on the outer structure of the star and on the presence or absence of matter around it. However, testing this theory requires the observation of the before and after moment a star becomes a supernova.

Melina Bersten, researcher at the Instituto de Astrofísica de La Plata, CONICET - UNLP, Argentina, and Visiting Associate Scientist at the Kavli Institute for the Physics and Mathematics of the Universe has said the chances of capturing such an event are slim, because it lasts for the order of one hour.

"If we think that on average each galaxy roughly produces one supernova per century, and that a century contains nearly 900 thousand hours, then the chance probability of observing the right galaxy at the right moment is not much greater than one in a million. However, the actual chances are smaller. One needs to take into account the facts that we can only see the galaxy during the night time and that the sky must be clear," she said.

Luckily, on September 20, 2016, amateur astronomer Vi?ctor Buso from Rosario, Argentina, was testing his new camera on his rooftop observatory in hope of photographing his first supernova. After an hour of taking images Buso noticed a new tiny object had appeared, and it became more obvious with time (Figure 1). He had captured the moment a supernova had exploded.

Named SN 2016gkg, a team of researchers including the Kavli Institute for the Physics and Mathematics of the Universe, and lead by Bersten, analyzed the images. The rapid brightening rate combined with a very low luminosity had no analogue among known supernovae, and the team concluded Buso had discovered SN 2016gkg during the shock breakout.

"When Buso told us how he had observed and what he had witnessed, we realized this was a unique finding," said Bersten.

Also, by comparing the photometry of the images with their computer simulations, the team found an initial sharp rise in supernova light that could only be explained by shock emergence (Figure 2).

"To our surprise, images had a great quality considering they were obtained from the middle of a large city in the midst of the pampas", notes Dr. Gasto?n Folatelli from IALP, who led the data analysis, and adds "sky conditions seem to have been nearly ideal on that night!"

Their conclusion was supported by the fact that the models required no modification in order to consistently reproduce the initial rise and the rest of the supernova evolution (Figure 3). Moreover, SN 2016gkg happened to be a rather ordinary event, which would imply that the observed phase is common to all supernovae, as models predict.

The team's results were published in Nature on February 22.
-end-


Kavli Institute for the Physics and Mathematics of the Universe

Related Supernova Articles from Brightsurf:

Scientists discover supernova that outshines all others
A supernova at least twice as bright and energetic, and likely much more massive than any yet recorded has been identified by an international team of astronomers, led by the University of Birmingham.

Supernova observation first of its kind using NASA satellite
Their research, detailed in the Monthly Notices of the Royal Astronomical Society, represents the first published findings about a supernova observed using TESS, and add new insights to long-held theories about the elements left behind after a white dwarf star explodes into a supernova.

Astronomers find possible elusive star behind supernova
Astronomers may have finally found a doomed star that seemed to have avoided detection before its explosive death.

Stellar thief is the surviving companion to a supernova
Hubble found the most compelling evidence that some supernovas originate in double-star systems.

Supernova may have 'burped' before exploding
Only by increasing the rate at which telescopes monitor the sky has it been possible to catch more Fast-Evolving Luminous Transients (FELTs) and begin to understand them.

An unusual white dwarf may be a supernova leftover
Astronomers have identified a white dwarf star in our galaxy that may be the leftover remains of a recently discovered type of supernova.

Researchers show how to make your own supernova
Researchers from the University of Oxford are using the largest, most intense lasers on the planet, to for the first time, show the general public how to recreate the effects of supernovae, in a laboratory.

The big star that couldn't become a supernova
For the first time in history, astronomers have been able to watch as a dying star was reborn as a black hole.

Seeing quadruple: Four images of the same supernova, a rare find
Galaxies bend light through an effect called gravitational lensing that helps astronomers peer deeper into the cosmos.

Explosive material: The making of a supernova
Pre-supernova stars may show signs of instability for months before the big explosion

Read More: Supernova News and Supernova Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.