Many millions or billions of years ago the fuel ran out of a giant star in Sagittarius constellation J1808, it collapsed under its own weight and exploded .
Such explosions often occur in the cosmos; Scientists know that they are part of a process that transforms powerful suns into shrunken neutron stars – the smallest and densest stars in the universe. What fascinated astronomers today about J1808 is the fact that it is still exploding apparently showering our galaxy with some of the most intense rays of light ever discovered.
August 20, 2019 A special neutron observing telescope aboard the International Space Station (ISS) recorded a thermonuclear explosion on J1
J1808 is a pulsar or neutron star that rotates extremely fast and emits strong electromagnetic radiation at both poles. Stars like this spin so fast (J1808 turns about 400 revolutions per second) that the energy jets at their poles seem to pulsate like flashlights every time they point to the earth. Neutron star can constantly suck in huge amounts of surrounding matter that is in a huge, swirling disc at the edge of the star (this is called "accretion disk"). According to the authors of the new study, J1808 seems to have spent a long time sucking hydrogen gas from a mysterious celestial object with which it shares a binary orbit. This object, which is larger than a planet and smaller than a star, carries the flattering cosmological collective term "brown dwarf".
The massive explosion observed on August 20 seems to be the result of a long one-sided relationship between J1808 and its brown partner, the researchers wrote. The neutron star seems to have absorbed so much hydrogen from its neighbor in recent years that the gas became a super-fast, super-dense "sea" that began to fall inward, covering the surface of the star. The heat of the star warmed the sea so much that a nuclear reaction began, fusing hydrogen nuclei into helium nuclei. Over time, this newly formed helium created a second layer of gas around the surface of the star that was several meters deep, the researchers wrote.
"Once the helium layer is a few meters deep, helium nuclei can merge into carbon under these conditions," said study co-author Zaven Arzoumanian, also with NASA, in the statement. "Then the helium explodes and releases a thermonuclear fireball over the entire surface of the pulsar."
The researchers believe the explosion took place on August 20, when such a fireball blasted away the hydrogen and helium layers surrounding the star in rapid succession, creating a double flash of intense, bright X-ray energy firing into space , (J1808 and his partner are about 11,000 light-years away from Earth, which is quite close cosmically.)
This interpretation of the explosion is in line with ISS observations, but leaves out an important detail. After the first two peaks of X-ray energy, the pulsar emitted a third, slightly muted explosion that was about 20% brighter than the star's normal flicker. It is not clear what mechanism triggered this last energy boost, the researchers said.
Originally published on Live Science .