An international team of astronomers has discovered a planet similar in mass to Jupiter orbiting a white dwarf. This is the first known planet to survive the death of its parent star without changing its orbit, according to scientists, whose article was published in the journal Nature.
Main sequence stars like the Sun, at the end of their evolution, generate all of their hydrogen in the core and turn into red giants, which then shed their outer shells and “shrink” into hard-to-find white dwarfs. In this case, most of the planets revolving around the star are destroyed.
Researchers from Australia, the United States and France using the Keck Observatory in Hawaii using gravitational microlensing – in which a closer object distorts the light of a farther star – were able to find a planet located 6.5 thousand light years from Earth, two kiloparsecs from the center of the Milky Way, , 40 percent heavier than Jupiter. However, searches for the parent star showed that it was not a main sequence star or a brown dwarf – its light was not bright enough.
“We were also able to rule out the possibility that it is a neutron star or a black hole. This means that the planet revolves around a dead star – a white dwarf. Thus, we can see what our solar system will look like after the disappearance of the Earth, ”- said one of the researchers, an employee of the Paris Institute of Astrophysics Jean-Philippe Beaulieu. The gas giants are believed to orbit white dwarfs at a distance of five to six astronomical units – but for a newly discovered planet, the distance was 2.8 astronomical units.
Despite the fact that existing models of the evolution of stellar systems show that planets of similar sizes and similar orbits can survive the death of their stars, it was not possible to find evidence of their existence before, astronomers emphasize.
