By chance, the Hubble space telescope was able to observe a supernova live last year and watch the end of a star “in real time”. This is now reported by a research team led by Ryan Foley from the University of California, Santa Cruz. The star explosion at a distance of 60 million light years was discovered in April 2020 at the Palomar Observatory, but the TESS space telescope had also already observed it there. Hubble and various observatories on earth were then quickly aligned with butterfly galaxies NGC 4567/8. This has resulted in the most extensive observation of a supernova to date, and at the same time, images up to 30 years old have shed light on its prehistory.
Crucial aid to astronomy
As Foley now explains, research into supernovae has so far been reminiscent of forensic evidence, which is always only on site after an act and has to determine what happened. Normally you only start observing days after a supernova, adds his colleague Samaporn Tinyanont. In the case of the star explosion with the designation SN 2020fqv it was different, you could react extremely quickly. Images from the TESS space telescope, which is actually looking for exoplanets, are therefore particularly valuable. The Transiting Exoplanet Survey Satellite takes pictures of a star region every 30 minutes in order to find minimal obscurations that indicate celestial bodies passing by. Coincidentally, it also took a lot of pictures of the star before it exploded.
By observing the supernova through so many telescopes, one could analyze the explosion with unprecedented accuracy, the team is happy. Among other things, the mass of the exploded star was determined in three different ways, and all three had the same results. According to this, the star had 14 to 15 times the mass of our sun. But above all, that underpinned the correctness of the methods. The astronomers therefore compare the star explosion with the famous Rosetta stone, which was decisive for deciphering the ancient Egyptian hieroglyphs. With the help of the large amount of data, it was possible to determine a real history of the supernova.
From several decades of data on the prehistory of the star explosion, they may have determined an advance warning system that could be used to predict future supernovae, they say. Although it is known that stars become more active before they can explode, the events surrounding the giant star Betelgeuse have shown how imprecise this is. Foley does not expect Betelgeuse to explode anytime soon, but the analyzes of SN 2020fqv have shown that one should be careful when a star begins to “wobble around”. Your supernova revealed the complex history of mass loss before a supernova. The study will appear in the journal Monthly Notices of the Royal Astronomical Society.