Two years ago, astronomers observed the end of the life of a massive star. The lack of hydrogen in this supernova explosion is significant. According to astronomers It did not match the image from a few years ago, and the object was still a yellow, hydrogen-frozen star.
Research project Young supernova experiment Scans the sky with a Hawaii telescope in search of newly erupted supernovae. In 2019, scientists saw something striking. Spiral galaxy NGC 4666 The supernova contains the 2019yvr, which does not appear to contain hydrogen.
The spectrum of light emitted by supernovae allows astronomers to accurately determine the amount of hydrogen. ‘We were able to observe even the smallest amount of hydrogen, 0.1 per cent of the total mass emitted by a supernova,’ says the astronomer. Charlie Gilpatrick From Northwestern University in the United Kingdom. ‘That’s why we conclude that this is a hydrogen-free supernova explosion.’
Yellow heavy star
To find out which star ended his life by this strange eruption, astronomers searched for old observations of the same area in the sky. They were lucky and discovered photos taken by the Hubble Space Telescope two and a half years before the star’s supernova eruption. It showed a yellow, massive star 35 million light-years away. This star is 320 times larger and seven times larger than the Sun.
These yellow supergiants usually have a warm, blue core hidden from view by the cold hydrogen mantle. This shield seemed to have disappeared when the star exploded.
This is the first time astronomers have seen such a thing. “We’ve already noticed more than 20 supernovae in the first few decades and several decades with the young supernova experiment,” says Gilpatrick. Many of them are stars very similar to the star type we identified as the precursor to Supernova 2019yvr. But these other supernovae have hydrogen. ‘2019yvr The lack of hydrogen puzzles astronomers.
Previous eruption or neighbors?
Astronomers present two scenarios for the disappearance of the hydrogen mantle. First, Gilpatrick says there may have been small explosions at the star in the throwing of hydrogen two years before the supernova erupted. “But we should have seen the material coming from the supernova collide with the remnants of a previously thrown hydrogen mantle.”
Another possibility is that a small star nearby tore the hydrogen mantle of the yellow supergiant. If this second scene is correct, this little asteroid is visible as the “supernova fog” is destroyed.
Astronomers need to be patient. It may take another ten years for the supernova to go out. Gilpatrick: ‘If the supernova remnant were left alone, we would have to reconsider the eruption situation.’