When astronomers look at heaven, they are not justlooking for objects whose existence we already know. They are also looking for evidence of physical phenomena that, in our opinion, should exist, but have not yet been found. When various factors are added to this equation — the vastness of the cosmos, the length of time of our searches, and the current quality of our tools — a mass of all sorts of things appear that we want to see but have not yet seen. The less often it occurs in the Universe, the more difficult it is to see it, such is the law.
Perhaps we recently found one of the most difficult objects to detect - an incredibly rare neutron star, which arose as a result of a collision of two white dwarfs.
What happens if two white dwarfs collide?
It is believed that the stars that are not enoughthe masses, to become neutron stars (and that’s almost all), end their lives with white dwarfs. White dwarfs are the remains of stars composed of extremely dense, degenerate matter. Their maximum stable mass is about 1.4 solar masses. This is known as Chandrasekhar limit. A white dwarf that gains enough mass to overcome this limit is so massive that the pressure of electron degeneration in the core of the star is no longer enough to withstand its own gravitational self-stress. At this point, the star explodes and becomes a neutron star or a black hole, in a classic type 1a supernova.
Or at least it should be. But scientists have discovered a stellar object J005311 with incredibly rare properties. This is a bright infrared star located inside a gas cloud, not emitting visible light. It is 40,000 times brighter than the Sun (in the infrared) and produces a powerful stellar wind that travels at a speed of 16,000 km / s. The typical solar wind speed of the largest stars is ~ 2000 km / s - this is for you to understand how fast this star rotates.
“First of all, these results show thatfusions of white dwarfs happen, ”says study co-author Goetz Grafener, an astronomer at Bonn University. “Secondly, it shows that some of these mergers do not end with an explosion.”
When the star is at the final stageher life, she begins to use for the synthesis of other materials in addition to hydrogen. What materials it can take for synthesis is determined by its density. The collision of two white dwarfs dramatically increases the density of the final object, allowing the synthesis of heavier elements. It is assumed that this will cause an increasing fusion reaction that will blow the star apart, but this has not happened in the case of J005311. Instead, the collision of two white dwarfs gave enough heat to ignite carbon without an explosion. As the star burns, it generates enough thermal pressure to prevent collapse and supernova that might otherwise occur. This is an incredibly rare phenomenon regarding the expected behavior of a pair of colliding white dwarfs.
And the temperature and wind speed circling inpresent around J005311, suggest that this object actually came to the end of its life. Given that the current mass is expected to be above the Chandrasekhar limit, and the life expectancy is only thousands of years, there is a very good chance that we caught J005311 during a tiny period of time when it is really possible to observe it. When the star explodes, it is likely to create a supernova type 1c with maximum luminosity.
If not seen, by the way, this is what a real black hole looks like. And in our Zen there are even more interesting things.