By Subashini Rajasuriah
Scientists have made headway in discovering nearly 5,000 planets all situated in our galaxy, the Milky Way.
However, just recently, the possible discovery of a Saturn sized planet by NASA’s Chandra X-ray telescope, is making headlines. This planet is in the Messier 51 galaxy, around 28 million light years away from the Milky Way.
If confirmed, this would be the first planet discovered beyond our galaxy which will be considered a major scientific breakthrough.
This new result is based on transits, where the passage of a planet in front of a star blocks some of the star’s light and yields a characteristic dip in brightness that can be detected by telescopes.
This method has been used prior to locate and identify thousands of exoplanets.
The uniqueness of this scenario is that they found the planet orbiting around a Neutron star which is also known as a dead star, and is part of a system that has been through a supernova explosion. This neutron star is seen to be pulling in gas from a closely orbiting companion star.
Neutron stars are formed when a huge star runs out of fuel and collapses. The very central region of the star – the core – collapses, merging every proton and electron into a neutron. This collapse leaves behind the densest object known – an object with the mass of a sun squished down to the size of a city.
Since neutron stars began their existence as stars, they are found scattered throughout the galaxy in the same places where we find stars. Like stars, they can be found by themselves or in binary systems with a companion much like the one we have discovered. In binary systems, some neutron stars can be found accreting materials from their companions, emitting electromagnetic radiation powered by the gravitational energy of the accreting material which is the case with this neutron star.
Scientists’ initial findings pointed towards the end of life in that solar system once the life of a star, met its end. However, this recent discovery has opened possibilities regarding further research into the survival of the planetary system after its host star dies.
With that being said, researchers will have to wait a significant amount of time to ascertain whether they have discovered an extragalactic exoplanet. Due to its large orbit, the planet candidate will not cross in front of the binary partner for another 70 years, meaning it could take decades to confirm the observation.