Warwick/RAS: Dead Planets Can 'Broadcast' for Up to a Billion Years
Posted: Thu Aug 08, 2019 8:21 pm
Dead Planets Can 'Broadcast' for Up to a Billion Years
University of Warwick, UK | Royal Astronomical Society | 2019 Aug 06
Survivability of Radio-Loud Planetary Cores Orbiting White Dwarfs ~ Dimitri Veras, Alexander Wolszczan
University of Warwick, UK | Royal Astronomical Society | 2019 Aug 06
Astronomers are planning to hunt for cores of exoplanets around white dwarf stars by ‘tuning in’ to the radio waves that they emit.
In new research ... scientists have determined the best candidate white dwarfs to start their search, based upon their likelihood of hosting surviving planetary cores and the strength of the radio signal that we can ‘tune in’ to.
... the research ... assesses the survivability of planets that orbit white dwarfs, stars which have burnt all of their fuel and shed their outer layers, destroying nearby objects and removing the outer layers of planets. They have determined that the cores which result from this destruction may be detectable and could survive for long enough to be found from Earth.
The first exoplanet confirmed to exist was discovered orbiting a pulsar ... in the 1990s, using a method that detects radio waves emitted from the star. The researchers plan to observe white dwarfs in a similar part of the electromagnetic spectrum in the hope of achieving another breakthrough.
The magnetic field between a white dwarf and an orbiting planetary core can form a unipolar inductor circuit, with the core acting as a conductor due to its metallic constituents. Radiation from that circuit is emitted as radio waves which can then be detected by radio telescopes on Earth. The effect can also be detected from Jupiter and its moon Io, which form a circuit of their own.
However, the scientists needed to determine how long those cores can survive after being stripped of their outer layers. Their modelling revealed that in a number of cases, planetary cores can survive for over 100 million years and as long as a billion years. ...
Survivability of Radio-Loud Planetary Cores Orbiting White Dwarfs ~ Dimitri Veras, Alexander Wolszczan
- Monthly Notices of the RAS 488(1):153 (Sep 2019) DOI: 10.1093/mnras/stz1721
- arXiv.org > astro-ph > arXiv:1906.08273 > 19 Jun 2019