In a far-off system that hints at what our own Solar System might look like in the distant future, astronomers have for the first time observed a Neptune-sized planet orbiting a hot white dwarf, that is so close, it's atmosphere is being stripped away.
"Such a system has never been seen before, and it was immediately clear to me that this was a unique star", lead researcher Boris Gänsicke from the University of Warwick in the United Kingdom said in a release. This pair was first found in a sample of 7,000 white dwarfs taken by the Sloan Digital Sky Survey. Scientists analyzed subtle variations in the light the system emitted to identify the elements present around the star.
"We knew that there had to be something exceptional going on in this system, and speculated that it may be related to some type of planetary remnant", Dr. Gänsicke explained.
To get a better idea of the properties of this unusual star, named WDJ0914+1914, the team analysed it with the X-shooter instrument on ESO's Very Large Telescope in the Chilean Atacama Desert. Using the Very Large Telescope of the European Southern Observatory in Chile to obtain more observations of this star, they found that the shape of the hydrogen, oxygen, and sulphur features are typical indicators of a ring of gas.More news: Leonardo DiCaprio's girlfriend Camilly Morrone defends 23-year age gap
"It took a few weeks of very hard thinking to figure out that the only way to make such a disk is the evaporation of a giant planet", said Matthias Schreiber, an astronomer at the University of Valparaiso in Chile, who was vital to determining the past and future evolution of the freakish system. Meanwhile, oxygen and sulfur-in addition to smaller amounts of hydrogen-from the planet fall towards the white dwarf, creating the disk of gas that was detected.
Due to the fact that the massive planet is located at such close distance to the white dwarf, the astronomers say it should have been eaten during the star's explosion phase; unless it moved inward after the star shifted into a white dwarf.
Until now, there has never been evidence of a planet that has survived a star's transition to a white dwarf.
The discovery is potentially groundbreaking as it suggests that there could be many more planets around such stars waiting to be discovered, possibly detectable using the transit method once the Large Synoptic Survey Telescope in Chile becomes operational by 2020. Since it orbits the hot white dwarf at close range, making its way around it in just 10 days, the high-energy photons from the star are gradually blowing away the planet's atmosphere. It is pulling its lost mass into a gas disc around the star at a rate of more than 3,000 tonnes per second. This disc is what gives away the presence of the otherwise hidden Neptune-like planet. "But because the star is so hot, it is evaporating the planet, and we detect the atmosphere it is losing".More news: Giannis Antetokounmpo scores 35 as Milwaukee Bucks win 13th straight
The good news here is that there may be a way to see our sun make it all the way to its white dwarf phase, so long as you're able to survive a few billion more years and able to relocate and survive on Jupiter or Saturn. When these stars finish burning their nuclear fuel, they'll first bloat up as enormous red giants, then eventually collapse down into white dwarfs, which pack about one solar mass into a sphere the size of Earth. After that, it'll swell into a red giant, and swallow Mercury, Venus, and probably Earth too. Eventually, there will be nothing left except the tiny core of the white dwarf slowly dimming away. According to the researchers, this is the first time that evidence of a huge planet orbiting such a star has been observed. All evidence points to this planet being a giant. This study puts an end to two decades of speculation that planets exist around white dwarfs, indicating that there could be many more that have yet to be identified, the researchers said. "There was the general agreement that those white dwarfs should have proper planets orbiting them, but none had been found so far". Sometimes stars like this had planetary systems before they died, and sometimes asteroids or even rocky planets can be disrupted by the dead star's fierce gravity.
"But somehow this newly-discovered planet has survived".
The discovery by astronomers from the University of Warwick's Department of Physics and the Millennium Nucleus for Planet Formation (NPF) at the University of Valparaiso is published in the journal Nature.More news: Real Madrid: Hazard to miss rest of 2020 and Barcelona Clásico