This star system is a good candidate for the closest type Ia supernova (one-A – only supernova from a binary star system) to Earth ever found.
Astronomers have discovered a rare teardrop-shaped star in the universe, about 1,500 light-years from the Sun.
Star in the shape of a water drop, illustration
So why is this star “crying”?
It’s because he’s in a “toxic relationship” with a literal mate, with his life being ripped from him. In star systems like this, there is no separation of stars; The romance only ends when the two stars explode together in a violent thermonuclear explosion visible to the entire galaxy. You will cry too.
However, astronomers (and cosmic paparazzi) are very interested in this newly discovered spiral star system with the number HD265435. It is one of only three known binary star systems in the universe It is also the closest star system to Earth. Its fate was destined to become a Type Ia Supernova explosion, according to a study published July 12 in the journal Nature Astronomy.
Supernova explosions of this type occur when a white dwarf star (the remnant of an old collapsed star) orbits around a younger, larger star while still having natural gas within itself to perform nuclear reactions in its nucleus. The white dwarf, though smaller but with great gravity, will deplete the remaining fuel, and also suck a large amount of material from the young star, causing that companion to begin to change shape from a sphere to an ellipse – or teardrop shaped. The old star grows over millions of years, eventually becoming so massive that nuclear reactions are reactivated in its core. As a result, the dwarf and the young companion will explode together in a supernova, and both will become a glowing trail of gas and dust in the night sky.
Normally, it would be easy to spot a supernova when it occurs (in 1054 AD, a famous supernova existed in Earth’s sky for 23 days and nights). But in this case, it is much more difficult to find a perished star system that led to an “Ia” type explosion. Part of the reason white dwarfs are extremely faint and small, but contain about the same mass as the Sun while being about the size of Earth, according to NASA.
Supernova explosion 10.5 billion light-years from Earth
At the same time, finding the white dwarf’s unfortunate companion is not easy. But because this young star tends to be brighter, it offers significant clues, according to the authors of the new study. The “ellipsoid” shape suggests that it has been deformed by gravity towards a massive object. Another clue is the fast-pulsing light signature, hinting at a binary star system where two stars orbit very quickly in extremely close proximity.
Using observations from NASA’s TESS space telescope, the researchers found that HD265435 meets both criteria. From these details, the team calculated the distance and mass of the bright star, allowing the researchers to make accurate estimates of the size and age of the companion star.
The team discovered that this young star has a mass 60% that of the Sun, which means it is on the verge of collapsing and becoming a white dwarf. As for its invisible companion, it perfectly meets the criteria of a white dwarf when it contains a mass equivalent to the Sun in a size barely smaller than that of the Earth.
The two stars complete an orbit around each other every 90 minutes or so, suggesting that they are very close to each other and will likely fully merge in millions of years. The authors come to the same conclusion This pair of stars has a total mass consistent with a type Ia supernova about to erupt in about 70 million years.
Obviously, none of us would be around at that time to see this binary system come to an end. But finding objective examples of exploding binary systems is not easy. Studying this star system and similar phenomena will help astronomers better understand the mysterious mechanisms that create explosions in this vast universe. Unfortunately for HD265435, this means space paparazzi lenses on Earth will be trained on star system relationships in later ages.
See more astronomical calendar 2021 here: https://deepsky2000.net/lich-cac-su-kien-thien-van-nam-2021/
HAS translation team: Kim Ngan