A fragment of the planet that survived the death of its star was discovered by astronomers at Warwick University on a disk of debris caused by destroyed planets, which the star eventually consumes.
Planetary, rich in iron and nickel, survived the systematic cataclysm following the death of its host star, SDSS J122859.93 + 104032.9. It is believed to have once been part of a larger planet, and its survival is even more astonishing because it is turning closer to its star than it used to be, possibly once every two hours.
The discovery, published in the Science magazine, is the first time scientists have used spectroscopy to detect a solid body in orbit around white dwarf, using the subtle variations in the light emitted to identify the extra gas that the planetomsimal creates.
Using the Gran Telescopio Canarias in La Palmi, scientists have been studying the disc that circulates around the white dwarf of a remote 410 light years, resulting from the interruption of rocky bodies made up of elements such as iron, magnesium, silicon and oxygen – the four key building blocks of the Earth and most rocky bodies. Within that disc, they discovered a gas ring flowing from a solid body like a comet's tail. This gas can be generated from the body itself or by evaporating the dust as it collides with small debris inside the disc.
Astronomers estimate that this body must be at least a kilometer long, but can be a few hundred kilometers in diameter, comparable to the most famous asteroids in our solar system.
White dwarves are the remnants of stars like ours who burned all the fuel and threw out their outer layers leaving behind a dense core that slowly cools over time. This star has dropped so dramatically that it spins planetally within the original Sun's radius. Evidence suggests that it was once part of the larger body still in its solar system and that it was probably a torn planet while the star started the cooling process.
The chief author of Dr. Christopher Manser, a research associate at the Department of Physics, said: "The star would originally be about two solar masses, but now the white dwarf is only 70% of the mass of our Sun. It is also very small – roughly the size of Earth – and it makes the star, and generally all white dwarfs, extremely dense.
"The weight of the white dwarf is so strong – about 100,000 times the Earth's size – that a typical asteroid will be torn to gravity forces if it goes too close to the white dwarf."
Professor Boris Gaensicke, co-author of the Department of Physics, adds: "The planetarium we discovered is deep in the gravity genius of a white dwarf, much closer to him than we would expect to find somewhat alive. This is possible only because it has to be very dense and / or very likely to have internal strength that holds it together, so we suggest it consists mainly of iron and nickel.
"If this pure iron could survive where it lives now, but it could equally be a body that is rich in iron, but with the inner power to hold it together, in keeping with the planet earth which is a rather massive fragment of planetary If this is true, the original body had a diameter of at least a hundred kilometers, because only then the planets begin to differentiate – such as oil on the water – and have the harder elements to turn into a metal core. "
The discovery offers a hint of what planets can reside in other solar systems and insight into our own future.
Dr. Christopher Manser said, "As a star, they grow into red giants that" cleans "most of the inner part of their planetary system. In our solar system, the Sun will expand to the place where Earth is currently circling, and will erase the Earth, Mercury and Mars. Mars will still survive and will continue to move out.
"The general consensus is that for now 5-6 billion years our solar system will be a white dwarf instead of the sun, circling around Mars, Jupiter, Saturn, outer planets, as well as asteroids and comets. Gravitation interactions are likely to occur in such remains of planetary systems, meaning larger planets can easily push smaller bodies to the orbit leading them close to the white dwarf, where their enormous gravity is destroyed.
"Learning about the masses of asteroids or planetary fragments that can reach a white dwarf can tell us something about the planets we know they need to be in this system, but we do not currently have the means to detect them.
"Our discovery is only another solidly planetsimal found in a narrow orbit around the white dwarf, previously found because the remains that pass in front of the star block some of its light – this is a" transit method "that is widely used to detect an exoplanet around a star-like star. To find such transitions, the geometry under which we look at them has to be very fine-tuned, meaning that every system observed for a few hours does not lead to anything. The spectroscopic method we developed in this research can detect close planets without the need for specific We already know about several other disk systems that are very similar to SDSS J122859.93 + 104032.9, which we will study next. We are confident that we will discover additional planets circulating around the white dwarfs, which will then enable us to find out more about their general properties. "
Publication: Christopher J. Manser, et al., "The Planetary Orbita within a Dwarf Disks around a White Dwarf Star", Science, Apr. 05, 2019: Vol. 364, Issue 6435, p. 66-69; DOI: 10.1126 / science.aat5330