Astronomers observe the precise moment when a star dies

The Hubble Space Telescope NASA has obtained a complete and unprecedented view of the first moments of the catastrophic disappearance of a star.

The Hubble data, combined with other observations of the star from ground-based and space telescopes, can give astronomers an early warning system for other

“We used to talk about the work of supernovae as if we were crime scene investigators, where we would show up after the fact and try to find out what happened to that star,” Ryan Foley of the University of California at Santa Cruz, leader of the team that made this discovery, explained in a statement. “This is a different situation, because really and we really see death in real time. “

it is found in the interacting butterfly galaxies, which are about 60 million light-years away in the constellation Virgo. It was discovered in April 2020 by the Zwicky Transient Facility at the Palomar Observatory in San Diego, California. Astronomers realized that the supernova was being observed simultaneously by the Transiting Exoplanet Survey Satellite (TESS), a NASA satellite designed primarily to discover exoplanets, with the ability to detect a variety of other phenomena. They quickly trained Hubble and a set of ground-based telescopes on it.

Together, these observatories gave the first holistic view of a star in the earliest stage of destruction. Hubble probed the material very close to the star, called circumstellar material, a few hours after the explosion. . These observations allowed astronomers to understand what was happening to the star just before it died.

“We can seldom examine this very close circumstellar material, since and generally we do not begin to observe a supernova until at least a few days after the explosion ”, explained Samaporn Tinyanont, first author of the study published in Monthly Notices of the Royal Astronomical Society. “For this supernova, we were able to make ultra-fast observations with Hubble, which provided unprecedented coverage of the region right next to the exploding star.”

The team analyzed Hubble observations of the star dating back to the 1990s. TESS provided an image of the system every 30 minutes starting several days before the explosion, through the explosion itself, and continuing for several weeks. Hubble was used again starting just hours after astronomers first detected the explosion. And by studying the circumstellar material with Hubble, scientists gained an understanding of what was happening around the star in the previous decade. By combining all of this information, the team was able to

“Now we have this whole story about what happened to the star in the years before his death, until the moment of death and after that”, Foley said. “This is really the most detailed view of stars like this in their final moments and how they explode.”

The Rossetta stone of supernovae

Tinyanont and Foley called SN 2020fqv “the Rosetta Stone of supernovae.” The ancient Rosetta Stone, which has the same text inscribed in three different scriptures, helped experts learn to read Egyptian hieroglyphs.

In the case of this supernova, the science team used three different methods to determine the mass of the exploding star. These included comparing the properties and evolution of the supernova with theoretical models; use information from a 1997 Hubble archive image of the star to rule out higher mass stars; and using observations to directly measure the amount of oxygen in the supernova, which probes the star’s mass. The results are all consistent: Accurately determining the mass of the star that explodes in a supernova is crucial to understanding how massive stars live and die.

“People use the term ‘Rosetta Stone’ a lot. But this is the first time that we have been able to verify mass with these three different methods for a supernova, and they are all consistent. “Tinyanont said. “Now we can move forward using these different methods and combining them, because there are many other supernovae where

In the years before the stars explode, they tend to become more active. Some astronomers point to the red supergiant Betelgeuse, which has recently been spewing significant amounts of material, and wonder if this star will soon go supernova. While Foley doubts that Betelgeuse will explode imminently,

“This could be an alert system”, Foley said. “So if you see a star start to shake a little bit, start to act, then maybe we should pay more attention and really try to understand what’s going on there before it explodes. As we find more and more supernovae of this type of we will be able to better understand what is happening in the last years of a star’s life ”.

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