According to a new study published by the Royal Astronomical Society, astronomers have discovered that the nucleus of a dead planet can broadcast radio waves for up to one billion years. Waves are caused by interactions between planets and dead fields known as white dwarfs.
After exploding, stars often disarm the surrounding planets from the atmosphere and outer layers, leaving only the core in the metal. The metal conducts electricity, creating a circuit between the core of the planet and a dead star that produces radiation in the form of radio waves.
Scientists have known for decades that the remnants of the planet can emit radio waves. But this is the first study that builds a lifetime for broadcasts and reveals signals long enough for researchers on Earth to detect and study them.
Alexander Wolszczan and Dimitri Veras, the scientists who made this discovery, then wanted to show a large telescope on a white dwarf star to listen to broadcasts from an undiscovered dead planet.
“Nobody has ever found only the core of a large planet before, or a planet only through monitoring magnetic signatures, or a large planet around a white dwarf. Therefore, the findings here will represent the first experience in three different senses for planetary systems,” he said, quoted from Science Alert, Tuesday (08/27/2019).
Broadcast from Dead Planet
Wolszczan, professor of astronomy at Penn State University, used radio waves to detect the first planet confirmed outside the solar system in the 1990s. For the latest research, he wants to determine how long radio broadcasts from dead planetary cores can last.
So, he and Veras created computer simulations of all ranges of magnetic fields and electrical conductivity observed in white dwarf stars. The results show the metal core of a dead planet can emit radio waves for more than 100 million years, sometimes even for one billion years.
Stars die because they end up burning hydrogen and helium reserves. The fuel creates internal pressure that makes the size and shape of the star consistent, but once there is nothing left to burn, the star dies due to gravity.
The core contracts send energy waves that push the outer layers out. When a star loses mass, its gravity weakens to explode and ejects its outer layers into space.
The hot, dense core of the star is left behind and this is the phase where the star becomes a white dwarf. The explosion destroyed nearby planets. However, the nucleus on a planet will remain in orbit around its dead star.
“In order for a core to reach that stage, the atmosphere and coat will be severely stripped at several points and thrown towards the white dwarf,” Veras said in a statement.