An artists performance of a red supergiant star transitioning into a Type II supernova, emitting a violent eruption of radiation and gas on its dying breath before exploding and collapsing. Credit: W. M. Keck Observatory/Adam Makarenko
Its another first for astronomy.
For the very first time, a team of astronomers have actually imaged in real-time as a red supergiant star reached completion of its life. They saw as the star convulsed in its death throes prior to lastly exploding as a supernova.
And their observations contradict previous thinking into how red supergiants act prior to they explode.
An artists impression of a red supergiant star in the last year of its life discharging a troubled cloud of gas. This suggests a minimum of some of these stars undergo substantial internal changes before going supernova. Credit: W.M. Keck Observatory/Adam Makarenko
A team of astronomers viewed the drama unfold through the eyes of 2 observatories in Hawaii: Pan-STARRS on Haleakala, Maui, and the W. M. Keck Observatory on Maunakea, Hawaii Island. Their observations were part of the Young Supernova Experiment (YSE) short-term study. They watched the supernova surge, named SN 2020tlf, during the final 130 days leading up to its detonation.
” For the very first time, we viewed a red supergiant star blow up!”– Wynn Jacobson-Galán, UC Berkeley
The title of the paper presenting the discovery is “Final Moments. I. Precursor Emission, Envelope Inflation, and Enhanced Mass Loss Preceding the Luminous Type II Supernova 2020tlf.” The paper is released in The Astrophysical Journal and the lead author is Wynn Jacobson-Galán, an NSF Graduate Research Fellow at UC Berkeley.
” This is a development in our understanding of what enormous stars do moments prior to they pass away,” said Jacobson-Galán, in a news release. “Direct detection of pre-supernova activity in a red supergiant star has actually never ever been observed prior to in a common Type II supernova. For the first time, we viewed a red supergiant star take off!”
” Its like seeing a ticking time-bomb.”– Raffaella Margutti, UC Berkeley
The discovery goes back to the Summer of 2020. At that time, the progenitor star experienced a significant rise in luminosity. Pan-STARRS identified that lightening up, and when Fall occurred the star blew up as SN 2020tlf. The supernova is a Type II supernova, where an enormous star experiences a quick collapse and after that takes off.
This video is an artists performance of the red supergiant star transitioning into a Type II supernova, producing a violent eruption of radiation and gas on its dying breath before collapsing and exploding. Credit: W. M. Keck Observatory/Adam Makarenko
The team utilized the Keck Observatorys Low-Resolution Imaging Spectrometer (LRIS) to capture the supernovas very first spectrum. When it took off, the LRIS data showed circumstellar material around the star. That material is most likely what Pan-STARRS saw the star ejecting in the summer prior to it exploded.
” Keck was important in supplying direct proof of a huge star transitioning into a supernova explosion,” said senior author Raffaella Margutti, an associate teacher of astronomy at UC Berkeley. “Its like seeing a ticking time bomb. Weve never verified such violent activity in a passing away red supergiant star where we see it produce such a luminous emission, then collapse and combust, previously.”
This figure from the study shows the supernova pre- and post-explosion. The middle panel reveals black-body temperatures in red, and the bottom panel reveals the radii in blue.
After the explosion, the group turned to other Keck instruments to continue their observations. Information from the DEep Imaging and Multi-Object Spectrograph (DEIMOS) and Near Infrared Echellette Spectrograph (NIRES) revealed that the progenitor star was 10 times more enormous than the Sun. The star remains in the NGC 5731 galaxy about 120 million light-years away.
The teams observations caused some brand-new insight into Type II supernovae and their progenitor stars. Prior to these observations, nobody had actually seen a red supergiant screen such a spike in luminosity and undergo such powerful eruptions prior to exploding. They were far more placid in their last days as if they accepted their fates.
Red supergiant stars eject product prior to core collapse. That material ejection takes location on much longer timescales than SN 2020tlf. This supernova discharged circumstellar product (CSM) for 130 days prior to collapse, which makes it a little bit of a puzzle. The brilliant flash prior to the stars explosion is somehow associated to the ejected CSM, but the group of scientists isnt specific how they all connected.
Artists impression of a Type II supernova explosion which involves the destruction of an enormous supergiant star. Credit: ESO
The substantial variability in the star leading up to collapse is puzzling. The powerful burst of light coming from the star prior to taking off suggests that something unknown occurs in its internal structure. Whatever those changes are, they result in a massive ejection of gas before the star blew up and collapsed.
In their paper, the authors discuss what may have triggered the ejection of gas. One possibility is wave-driven mass loss, which occurs in the late stages of excellent advancement. It takes place when the “… excitation of gravitational waves by oxygen or neon burning in the last years prior to SN can permit for the injection of energy into the external stellar layers, resulting in an inflated envelope and/or eruptive mass-loss episodes,” they compose. Present wave-driven designs do not match the progenitor stars ejection of gas. Theyre constant with the progenitor stars radius in its last 130 days, but not consistent with the burst of luminosity.
“Given the progenitor mass variety obtained from nebular spectra, it is likely that the boosted mass loss and precursor emission are the results of instabilities deeply rooted in the outstanding interior, most likely associated with the last nuclear burning phases. Energy deposition from either gravitational waves produced in neon/oxygen burning stages or a silicon flash in the progenitors final?
If theres one supernova that acts like this, there must be more. The teams findings indicate that surveys like the Young Supernova Experiment short-term study now have a method to discover more of them in the future. If the study finds more stars ejecting product like this one, then they understand to keep an eye on it to see if it collapses and blows up.
” I am most excited by all of the brand-new unknowns that have been opened by this discovery,” stated Jacobson-Galán. “Detecting more events like SN 2020tlf will drastically affect how we specify the final months of outstanding evolution, joining observers and theorists in the quest to fix the secret of how huge stars spend the last moments of their lives.”
Initially released on Universe Today.
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“Direct detection of pre-supernova activity in a red supergiant star has never ever been observed prior to in a normal Type II supernova. For the very first time, we enjoyed a red supergiant star take off!”
The supernova is a Type II supernova, where a huge star experiences a fast collapse and then takes off.
” Keck was important in offering direct proof of a massive star transitioning into a supernova surge,” said senior author Raffaella Margutti, an associate professor of astronomy at UC Berkeley. The teams observations led to some brand-new insight into Type II supernovae and their progenitor stars.